[Emc-users] Ladder Modbus Slave

[Kirk Wallace]

Why does LinuxCNC's Ladder have a Modbus slave? Does anyone use it? I'm
looking into using it for testing a LinuxCNC TCP master, but wondered if
it might be used elsewhere. I'd also like to get an idea of how many
people use PLC's and/or ModbusTCP with LinuxCNC.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Dave]

On 2/26/2012 3:47 PM, Kirk Wallace wrote:
> Why does LinuxCNC's Ladder have a Modbus slave? Does anyone use it? I'm
> looking into using it for testing a LinuxCNC TCP master, but wondered if
> it might be used elsewhere. I'd also like to get an idea of how many
> people use PLC's and/or ModbusTCP with LinuxCNC.
>


I think the Modbus slave (Modbus server) only works in TCP mode. I have
never tried it but it could be very useful for linking two
LinuxCNC boxes. I have tested the TCP master but never used Modbus TCP
on an actual application.

Most of my LinuxCNC applications include a PLC as the I/O is cheap and
flexible but I usually use a RS232 or RS485 link.

The external PLC allows some of the processing to be offloaded to the
PLC for functions external to the CNC functionality.

I think the Modbus TCP slave functionality was part of Classic Ladder so
it was integrated along with the rest of the Classic Ladder package into
LinuxCNC.

Chris Morley would know a lot more than I do about the history.

Dave

[Jan de Kruyf]

Hallo,
Using ModbusTCP will give LinuxCNC just a slightly more industrial look.
So I would very much vote to keep that! and even expand on it.
It makes it just a little bit easier to sell.

Cheers,

j.

On Sun, Feb 26, 2012 at 10:47 PM, Kirk Wallace
<***@wallacecompany.com>wrote:

> Why does LinuxCNC's Ladder have a Modbus slave? Does anyone use it? I'm
> looking into using it for testing a LinuxCNC TCP master, but wondered if
> it might be used elsewhere. I'd also like to get an idea of how many
> people use PLC's and/or ModbusTCP with LinuxCNC.
> --
> Kirk Wallace
> http://www.wallacecompany.com/machine_shop/
> http://www.wallacecompany.com/E45/index.html
> California, USA
>
>
>
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[Kirk Wallace]

On Mon, 2012-02-27 at 09:17 +0200, Jan de Kruyf wrote:
> Hallo,
> Using ModbusTCP will give LinuxCNC just a slightly more industrial look.
> So I would very much vote to keep that! and even expand on it.
> It makes it just a little bit easier to sell.
>
> Cheers,
>
> j.

Yes, Modbus doesn't seem to want to die and is handy for VFD's and
PLC's. The point I was try to explore is why LinuxCNC has a slave
feature as well as the master feature. VFD's and PLC's are slaves and
provide services to LinxCNC, so why would I want to have LinuxCNC be a
slave? This could allow two LinuxCNC PC's to talk to each other, but I
would think there are easier ways to do this. I think the feature is
there because it is part of the Modbus package and got a free ride. It's
no big deal, I was just curious, but I might want to give it some
attention if someone is actually using it.

I use Modbus with VFD's and some time in the future maybe an AVR tool
changer controller, others use it with PLC's. My plan so far is to keep
any focus I may have on those items.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Chris Morley]

>
> Yes, Modbus doesn't seem to want to die and is handy for VFD's and
> PLC's. The point I was try to explore is why LinuxCNC has a slave
> feature as well as the master feature. VFD's and PLC's are slaves and
> provide services to LinxCNC, so why would I want to have LinuxCNC be a
> slave? This could allow two LinuxCNC PC's to talk to each other, but I
> would think there are easier ways to do this. I think the feature is
> there because it is part of the Modbus package and got a free ride. It's
> no big deal, I was just curious, but I might want to give it some
> attention if someone is actually using it.
>
> I use Modbus with VFD's and some time in the future maybe an AVR tool
> changer controller, others use it with PLC's. My plan so far is to keep
> any focus I may have on those items.
> --

As was mentioned Modbus master/slave is incorporated with Classicladder.
Version 7.100 (the first version included in EMC2) actually had Modbus in
the source - it was just turned off.
When I updated EMC2 to the 7.124 version, I decided to include it.

I personally never got the slave version to work but that is probably because
I don't understand TCP connections.
Do you connect two computers with crossover cable or must you use a router?
How do you find the address?

Marc (Classicladders creator) tells me he has tested it and it worked.
He just never supplied step by step instructions.

I can see no reason not to have a slave feature. If you have a separate computer
you could use it as a smart PLC without slowing down your main computer.
or have the second computer run windows (CL runs in windows too)
The original CL was made to be able to be included in embedded machines.

Also it would allow you to test your Modbus connection which is probably why
Marc coded it.

If you figure out how to use it please add it to the official docs.

Chris M

[Jan de Kruyf]

Well now. . .
If I wanted to set up a Proview Scada system (http://www.proview.se/) with
some autonomous material handling robots
here and there, this modbus slave feature might just come in very handy.
Just for a bit of interlocking, nothing fancy.
So speed is not at all important, neither is advanced data handling.

Or even for communication with an advanced toolchanger setup with an
extended toolstore. A single station LCNC (EMC) will be
totally lost without a dedicated tool exchange computer in such cases.
And why must LCNC poll the toolchanger contimually, there might just as
well be a second channel where the toolchanger
is the master.

My 1/2 cents (SouthAfrican) worth.

j.


On Mon, Feb 27, 2012 at 7:37 PM, Chris Morley <***@hotmail.com>wrote:

>
>
>
> >
> > Yes, Modbus doesn't seem to want to die and is handy for VFD's and
> > PLC's. The point I was try to explore is why LinuxCNC has a slave
> > feature as well as the master feature. VFD's and PLC's are slaves and
> > provide services to LinxCNC, so why would I want to have LinuxCNC be a
> > slave? This could allow two LinuxCNC PC's to talk to each other, but I
> > would think there are easier ways to do this. I think the feature is
> > there because it is part of the Modbus package and got a free ride. It's
> > no big deal, I was just curious, but I might want to give it some
> > attention if someone is actually using it.
> >
> > I use Modbus with VFD's and some time in the future maybe an AVR tool
> > changer controller, others use it with PLC's. My plan so far is to keep
> > any focus I may have on those items.
> > --
>
> As was mentioned Modbus master/slave is incorporated with Classicladder.
> Version 7.100 (the first version included in EMC2) actually had Modbus in
> the source - it was just turned off.
> When I updated EMC2 to the 7.124 version, I decided to include it.
>
> I personally never got the slave version to work but that is probably
> because
> I don't understand TCP connections.
> Do you connect two computers with crossover cable or must you use a router?
> How do you find the address?
>
> Marc (Classicladders creator) tells me he has tested it and it worked.
> He just never supplied step by step instructions.
>
> I can see no reason not to have a slave feature. If you have a separate
> computer
> you could use it as a smart PLC without slowing down your main computer.
> or have the second computer run windows (CL runs in windows too)
> The original CL was made to be able to be included in embedded machines.
>
> Also it would allow you to test your Modbus connection which is probably
> why
> Marc coded it.
>
> If you figure out how to use it please add it to the official docs.
>
> Chris M
>
>
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[Kirk Wallace]

On Mon, 2012-02-27 at 17:37 +0000, Chris Morley wrote:
... snip
> I personally never got the slave version to work but that is probably because
> I don't understand TCP connections.
> Do you connect two computers with crossover cable or must you use a router?
> How do you find the address?

There may be a function that can look this up, but I think it's hard for
the API to know what network the app needs to use, although 99% of the
time the host has a single Ethernet port making the practical choice
easy. I got the libmodbus 3 unit-test demo to work by just doing a
ifconfig to to get my IP address and plugged that in. That's all that
was needed. RTU over TCP is probably a different story. My LinuxCNC
master could send queries just fine, but the unit-test slave isn't set
up to return anything interesting. Successes for unit-test demo seems to
be a lack of error messages.

> Marc (Classicladders creator) tells me he has tested it and it worked.
> He just never supplied step by step instructions.
>
> I can see no reason not to have a slave feature. If you have a separate computer
> you could use it as a smart PLC without slowing down your main computer.
> or have the second computer run windows (CL runs in windows too)
> The original CL was made to be able to be included in embedded machines.
>
> Also it would allow you to test your Modbus connection which is probably why
> Marc coded it.
>
> If you figure out how to use it please add it to the official docs.
>
> Chris M

I don't know Ladder so I'm not much help with related issues, but I plan
on recording what a learn with libmodbus.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Chris Morley]

>
> There may be a function that can look this up, but I think it's hard for
> the API to know what network the app needs to use, although 99% of the
> time the host has a single Ethernet port making the practical choice
> easy. I got the libmodbus 3 unit-test demo to work by just doing a
> ifconfig to to get my IP address and plugged that in. That's all that
> was needed. RTU over TCP is probably a different story. My LinuxCNC
> master could send queries just fine, but the unit-test slave isn't set
> up to return anything interesting. Successes for unit-test demo seems to
> be a lack of error messages.
>

CL requires the address and the port number (9502 id default).
I somewhat understand the address but not really the port number.
Can you elaborate how you found this info? keep in mind I have
almost no knowledge of networks other then plugging in my ethernet cable
in to my cable internet router. :)

Chris M

[Jan de Kruyf]

http://www.modbus-ida.org/tech.php

j.

On Mon, Feb 27, 2012 at 9:48 PM, Chris Morley <***@hotmail.com>wrote:

>
>
> >
> > There may be a function that can look this up, but I think it's hard for
> > the API to know what network the app needs to use, although 99% of the
> > time the host has a single Ethernet port making the practical choice
> > easy. I got the libmodbus 3 unit-test demo to work by just doing a
> > ifconfig to to get my IP address and plugged that in. That's all that
> > was needed. RTU over TCP is probably a different story. My LinuxCNC
> > master could send queries just fine, but the unit-test slave isn't set
> > up to return anything interesting. Successes for unit-test demo seems to
> > be a lack of error messages.
> >
>
> CL requires the address and the port number (9502 id default).
> I somewhat understand the address but not really the port number.
> Can you elaborate how you found this info? keep in mind I have
> almost no knowledge of networks other then plugging in my ethernet cable
> in to my cable internet router. :)
>
> Chris M
>
>
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[Kirk Wallace]

On Mon, 2012-02-27 at 19:48 +0000, Chris Morley wrote:
>
> >
> > There may be a function that can look this up, but I think it's hard for
> > the API to know what network the app needs to use, although 99% of the
> > time the host has a single Ethernet port making the practical choice
> > easy. I got the libmodbus 3 unit-test demo to work by just doing a
> > ifconfig to to get my IP address and plugged that in. That's all that
> > was needed. RTU over TCP is probably a different story. My LinuxCNC
> > master could send queries just fine, but the unit-test slave isn't set
> > up to return anything interesting. Successes for unit-test demo seems to
> > be a lack of error messages.
> >
>
> CL requires the address and the port number (9502 id default).
> I somewhat understand the address but not really the port number.
> Can you elaborate how you found this info? keep in mind I have
> almost no knowledge of networks other then plugging in my ethernet cable
> in to my cable internet router. :)
>
> Chris M

I'm not sure of the proper terminology and I'm learning as I go, but
each network node or Ethernet connection has an address like
192.168.1.10, then services that can be provided on a network node have
a port number. So when LinuxCNC makes a request it gets routed to the
network card that has the proper address, then the card routes the
request to the proper service by using the port number. If the request
was for an HTML web page or FTP file transfer, the address would be the
same but the port number would be different. ModbusTCP seems to have a
default address of 502, but it really could be anything. Addresses above
1000 are handled with fewer restrictions, the libmodbus demo selects
port 1502 so the demo doesn't need to be run as root. You can see active
ports of services your computer is providing from the desktop here:
System > Administration > Network Tools > Netstat > Active Network
Services

For libmodbus 3 it seems the slave address(es) needs to be determined
and entered in both the master component, so the master knows which
slave to talk to, and the slave driver, so the slave knows which
Ethernet card and service port to listen to for requests. libmodbus has
a feature called ModbusTCP/IP that can use a hostname to find the
network address, but I haven't looked into it yet.

There is another variation of ModbusTCP for using Ethernet to serial
port bridges where the network information and the serial port
information need to be included within the Modbus packet in order to
find the proper slave.

--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Dave]

On 2/27/2012 2:48 PM, Chris Morley wrote:
>
>
>> There may be a function that can look this up, but I think it's hard for
>> the API to know what network the app needs to use, although 99% of the
>> time the host has a single Ethernet port making the practical choice
>> easy. I got the libmodbus 3 unit-test demo to work by just doing a
>> ifconfig to to get my IP address and plugged that in. That's all that
>> was needed. RTU over TCP is probably a different story. My LinuxCNC
>> master could send queries just fine, but the unit-test slave isn't set
>> up to return anything interesting. Successes for unit-test demo seems to
>> be a lack of error messages.
>>
>>
> CL requires the address and the port number (9502 id default).
> I somewhat understand the address but not really the port number.
> Can you elaborate how you found this info? keep in mind I have
> almost no knowledge of networks other then plugging in my ethernet cable
> in to my cable internet router. :)
>
> Chris M
>
> ------------------------------------------------------------------------------
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>

Chris,

I found a Windows based Modbus test software package on the web and used
that to test the Modbus TCP functions a while back.
It was very easy to establish a link between the Windows box and CL. I
had to setup the IP addresses, and port numbers on each computer but
after that everything came up and ran.
I first tried it with a simple switch and then went to a crossover cable
- both worked.
The Modbus test software was really nice since it displayed the packets.
I never tried the Modbus TCP slave functions but I would like to set
that up some day.

Dave

[Chris Morley]

> > CL requires the address and the port number (9502 id default).
> > I somewhat understand the address but not really the port number.
> > Can you elaborate how you found this info? keep in mind I have
> > almost no knowledge of networks other then plugging in my ethernet cable
> > in to my cable internet router. :)
> >
> > Chris M
> >

When I fire up classicladder (I'm using the parent version not EMC's)
then run sudo netstat -anp --tcp
I see:
tcp 0 0 0.0.0.0:9503 0.0.0.0:* LISTEN 20701/classicladder

so that is address 0.0.0.0 port 9502 and its waiting for someone to connect to it.

I can change the port number.
I'm not sure how to change that address.

Chris M

[Kirk Wallace]

On Tue, 2012-02-28 at 07:03 +0000, Chris Morley wrote:
... snip
> When I fire up classicladder (I'm using the parent version not EMC's)
> then run sudo netstat -anp --tcp
> I see:
> tcp 0 0 0.0.0.0:9503 0.0.0.0:* LISTEN 20701/classicladder
>
> so that is address 0.0.0.0 port 9502 and its waiting for someone to connect to it.
>
> I can change the port number.
> I'm not sure how to change that address.
>
> Chris M

My guess is that anywhere you would put the serial slave address one can
put the TCP address instead. If you are already changing the port, just
put the IP address in with it, maybe like:
"192.168.1.10:9502"
^^^IP ADR^^^:^Port

It looks like this can be entered as an option on the loadrt or loadusr
command line or in the GUI set up under Slave Address. Just find the
address of the slave, maybe with ifconfig on the slave (if it is a Linux
slave) and the port number that was used when loading or setting up the
slave.

BTW, the above shows the port as 9503 instead of 9502, so in this case
the master will need to point to 9503.

Usually a computer has one Ethernet port, but could have more. Another
standard port is called a loopback which I gather is used for some
software that needs a network but doesn't need to talk outside of the
computer. It's address is 127.0.0.0 or named loopback:
http://en.wikipedia.org/wiki/Localhost

With this, one can connect the Mobus master and slave on the same PC, I
suppose mostly for testing.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Stephen Dubovsky]

We use modbus & modbus/ip in our products here. For IP, you need both an
ip addr/port AND the modbus slave address. Each device can have
240-something addresses. Think of an IP to RS485 bridge (moxa and others
make them). I can talk to any of the slave devices by their modbus address
though one (the bridge's) IP addr/port.

Modbus/IP is just a wrapper for a RS232/485 modbus packet.

Stephen

[Kirk Wallace]

On Tue, 2012-02-28 at 13:27 -0500, Stephen Dubovsky wrote:
> We use modbus & modbus/ip in our products here. For IP, you need both an
> ip addr/port AND the modbus slave address. Each device can have
> 240-something addresses. Think of an IP to RS485 bridge (moxa and others
> make them). I can talk to any of the slave devices by their modbus address
> though one (the bridge's) IP addr/port.
>
> Modbus/IP is just a wrapper for a RS232/485 modbus packet.
>
> Stephen

Just to clarify a little (or create confusion if I got this wrong),
Modbus RTU, Modbus ASCII and Modbus over TCP/IP do need a slave address
because the end point is a serial device (the IP address and port is for
the gateway or bridge device). Modbus TCP does not use a slave address,
or rather, the slave address is the IP address and port number (often
omitted if using the default of 502) since the end point is an Ethernet
device.

It seems that Modbus over TCP/IP setups are more common in the wild than
end to end Ethernet Modbus TCP/IP, but if one where to set up LinuxCNC
as a Modbus slave (currently only TCP/IP), it would be one of those
exceptions. It's good news/bad news. The good news is, Modbus has a lot
of options, the bad news, Modbus has a lot of options.

http://en.wikipedia.org/wiki/Modbus#Protocol_versions


--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Michael Haberler]

Am 28.02.2012 um 20:12 schrieb Kirk Wallace:
>
> It seems that Modbus over TCP/IP setups are more common in the wild than
> end to end Ethernet Modbus TCP/IP, but if one where to set up LinuxCNC

the vfs11_vfd driver I pushed yesterday is a Modbus master which suppports serial as well as in/outgoing TCP connections, and the plumbing is all in place

so if you want to support a new Modbus device you'd better off basing code on vfs11_vfd than on gs2_vfd

-m

[Kirk Wallace]

On Tue, 2012-02-28 at 20:31 +0100, Michael Haberler wrote:
> Am 28.02.2012 um 20:12 schrieb Kirk Wallace:
> >
> > It seems that Modbus over TCP/IP setups are more common in the wild than
> > end to end Ethernet Modbus TCP/IP, but if one where to set up LinuxCNC
>
> the vfs11_vfd driver I pushed yesterday is a Modbus master which suppports serial as well as in/outgoing TCP connections, and the plumbing is all in place
>
> so if you want to support a new Modbus device you'd better off basing code on vfs11_vfd than on gs2_vfd

I see that someone has been busy. It will take some time for me to
review your new vfs11 code. In my project, I have split the serial port
function out of the device component so that multiple device components
can share one serial port. It seems with ModbusTCP/IP and maybe Modbus
over TCP/IP the the port specific functions are already segregated and
there is no resource locking as with the serial port. I am tending
towards having a number of smaller focused components, a device
component for each model and a port component for each port as needed.
An integrator would choose a device component and port component that
matched the hardware and network being used, rather than one big catch
all component. I keep getting side tracked, but I think my focus should
be on formalizing a serial port component, VFD and PLC device components
with very basic functions, and a means to sequence device queries to the
port component. Frankly, I'm beginning to lose steam on this one and I
have an IRAMS coming in the mail, so it may take a while to get
something significant done.

http://wallacecompany.com/machine_shop/EMC2/Screenshot-12.png
http://wallacecompany.com/machine_shop/EMC2/mbrtuport.c
http://wallacecompany.com/machine_shop/EMC2/sj200mbbasic.comp

--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Kirk Wallace]

On Tue, 2012-02-28 at 09:48 -0800, Kirk Wallace wrote:
... snip
> My guess is that anywhere you would put the serial slave address one can
> put the TCP address instead. If you are already changing the port, just
> put the IP address in with it, maybe like:
> "192.168.1.10:9502"
> ^^^IP ADR^^^:^Port
... snip

I just noticed the command line option "--modbus_port". I'm wondering if
this means "modbus_slave_address"? If so, "--modbus_port
192.168.1.10:9503" might be appropriate. Although, at the moment I can't
seem to get anything other than the demo to start, so that shows you
what I know.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Michael Haberler]

no, that's the TCP destination port, nothing todo with the slave

A TCP connection is defined by {sourceip-address,some source port, destip-address,destination port}
once established, it's just a bidirectional stream of bytes with no interpretation, just like a serial connection over /dev/ttySomething

a Modbus slave number tells one of the parties how to interpret the stuff coming in/going out over this stream

-m


Am 28.02.2012 um 19:24 schrieb Kirk Wallace:

> On Tue, 2012-02-28 at 09:48 -0800, Kirk Wallace wrote:
> ... snip
>> My guess is that anywhere you would put the serial slave address one can
>> put the TCP address instead. If you are already changing the port, just
>> put the IP address in with it, maybe like:
>> "192.168.1.10:9502"
>> ^^^IP ADR^^^:^Port
> ... snip
>
> I just noticed the command line option "--modbus_port". I'm wondering if
> this means "modbus_slave_address"? If so, "--modbus_port
> 192.168.1.10:9503" might be appropriate. Although, at the moment I can't
> seem to get anything other than the demo to start, so that shows you
> what I know.
> --
> Kirk Wallace
> http://www.wallacecompany.com/machine_shop/
> http://www.wallacecompany.com/E45/index.html
> California, USA
>
>
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[Dave]

On 2/28/2012 2:03 AM, Chris Morley wrote:
>
>
>
>>> CL requires the address and the port number (9502 id default).
>>> I somewhat understand the address but not really the port number.
>>> Can you elaborate how you found this info? keep in mind I have
>>> almost no knowledge of networks other then plugging in my ethernet cable
>>> in to my cable internet router. :)
>>>
>>> Chris M
>>>
>>>
> When I fire up classicladder (I'm using the parent version not EMC's)
> then run sudo netstat -anp --tcp
> I see:
> tcp 0 0 0.0.0.0:9503 0.0.0.0:* LISTEN 20701/classicladder
>
> so that is address 0.0.0.0 port 9502 and its waiting for someone to connect to it.
>
> I can change the port number.
> I'm not sure how to change that address.
>
> Chris M
>
>

The IP address is set via Linux for your computer.. it is under
administrator, network something. I don't that that Linux or Windows
considers 0.0.0.0 a legitimate IP address, meaning it has not be configured.

I think that Linux comes out of the box setup for DHCP so that it asks
what IP address it should be and if a router assigns it an address that
is what it becomes.

When I was doing the Modbus TCP testing, I first had my laptop and the
Linux/EMC2 box on the same network and my router assigned both devices
an IP address. (OK, so I am lazy. if the computer can get onto the
web, I know it has a legit IP address.)
So it was a simple matter set the slave address in EMC2 to the IP
address of my laptop that was running the Modbus test software.

Once the addresses were set I also tried the same setup without a switch
via a point to point crossover ethernet cable and that worked fine as
well. Since both computers were already assigned IP addresses by my
network router, they didn't have to be changed.

My router ( a linksys) assigns itself as 192.168.1.1 and then assigns
any device using DHCP addresses starting at 192.168.1.100 and goes up
from there. I think that Netgear uses addresses that start at 10. for
whatever reason.

Dave

[Kirk Wallace]

On Tue, 2012-02-28 at 07:03 +0000, Chris Morley wrote:
... snip
> When I fire up classicladder (I'm using the parent version not EMC's)
> then run sudo netstat -anp --tcp
> I see:
> tcp 0 0 0.0.0.0:9503 0.0.0.0:* LISTEN 20701/classicladder
>
> so that is address 0.0.0.0 port 9502 and its waiting for someone to connect to it.
>
> I can change the port number.
> I'm not sure how to change that address.
>
> Chris M
... snip

I think I know a little more now. I was able to bring up
"loadusr classicladder --modslave" (I didn't know the rt component had
to be loaded too). My netstat returned the same result above with
"0.0.0.0:9502". I then did a ifconfig to find my network computer's
addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
listed. I nmap both addresses and found port 9502 open on both, so it
seems by default, "--modslave" will listen on all addresses (two in this
case), with "all or any addresses" being called out as "0.0.0.0".
http://en.wikipedia.org/wiki/0.0.0.0

If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
previously. My guess is that as any ports above 1000 have lighter
restrictions, maybe ports above a higher value are handled differently
too, so 1502 doesn't show where 9502 does. I guess I have more work to
do.

I haven't tried connecting to the LinuxCNC slave with a master yet.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Kirk Wallace]

On Tue, 2012-02-28 at 14:21 -0800, Kirk Wallace wrote:
... snip
> My guess is that as any ports above 1000 have lighter
> restrictions, maybe ports above a higher value are handled differently
> too, so 1502 doesn't show where 9502 does. I guess I have more work to
> do.

Oops, pilot error here. The 1502 and 9502 port or any port number show
up and work just fine.

> I haven't tried connecting to the LinuxCNC slave with a master yet.

Modpoll (master) connects and seems to query coils starting from 1, but
querying registers didn't work for any of the addresses I guessed at. I
haven't found any documentation for the CL slave so finding registers or
how to use the slave in general might be difficult.

In poking around the Classic Ladder site I found what might be
interesting, a CL hardware slave, it might come in handy:
http://sites.google.com/site/classicladder/classicladder_io_module

It's open source and AVR based so it's gotta be good.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA

[Mark Wendt]

On 02/28/2012 05:21 PM, Kirk Wallace wrote:
> ... snip
>
> I think I know a little more now. I was able to bring up
> "loadusr classicladder --modslave" (I didn't know the rt component had
> to be loaded too). My netstat returned the same result above with
> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
> listed. I nmap both addresses and found port 9502 open on both, so it
> seems by default, "--modslave" will listen on all addresses (two in this
> case), with "all or any addresses" being called out as "0.0.0.0".
> http://en.wikipedia.org/wiki/0.0.0.0
>
> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
> previously. My guess is that as any ports above 1000 have lighter
> restrictions, maybe ports above a higher value are handled differently
> too, so 1502 doesn't show where 9502 does. I guess I have more work to
> do.
>
> I haven't tried connecting to the LinuxCNC slave with a master yet.
>
Actually, ports 1024 and below are considered "privileged" ports. Any
ports above that are considered "non-privileged" ports and are all
treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
port shows up.

Mark

[Peter Homann]

Hi,

Port 502 is assigned to Modbus, so that's what slaves should use by default.

Cheers,


Peter.

On 29/02/2012 9:40 PM, Mark Wendt wrote:
> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>> ... snip
>>
>> I think I know a little more now. I was able to bring up
>> "loadusr classicladder --modslave" (I didn't know the rt component had
>> to be loaded too). My netstat returned the same result above with
>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>> listed. I nmap both addresses and found port 9502 open on both, so it
>> seems by default, "--modslave" will listen on all addresses (two in this
>> case), with "all or any addresses" being called out as "0.0.0.0".
>> http://en.wikipedia.org/wiki/0.0.0.0
>>
>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>> previously. My guess is that as any ports above 1000 have lighter
>> restrictions, maybe ports above a higher value are handled differently
>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>> do.
>>
>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>
> Actually, ports 1024 and below are considered "privileged" ports. Any
> ports above that are considered "non-privileged" ports and are all
> treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
> port shows up.
>
> Mark
>
>
> ------------------------------------------------------------------------------
> Virtualization& Cloud Management Using Capacity Planning
> Cloud computing makes use of virtualization - but cloud computing
> also focuses on allowing computing to be delivered as a service.
> http://www.accelacomm.com/jaw/sfnl/114/51521223/
> _______________________________________________
> Emc-users mailing list
> Emc-***@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

--
-----------------------------------------------------------------------------
eStore: http://www.homanndesigns.com/store
Web : http://www.homanndesigns.com ModIO - Modbus Interface Unit
email : ***@homanndesigns.com DigiSpeed - Isolated 10Vdc I/F
Phone : [phone] TurboTaig - Taig Mill Upgrade board

[Mark Wendt]

Peter,

I was referring to Kirk's not seeing port 1502 after he assigned it in
the loadusr statement, and how the OS handles ports above 1024.

Mark

On 02/29/2012 06:07 AM, Peter Homann wrote:
> Hi,
>
> Port 502 is assigned to Modbus, so that's what slaves should use by default.
>
> Cheers,
>
>
> Peter.
>
> On 29/02/2012 9:40 PM, Mark Wendt wrote:
>
>> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>>
>>> ... snip
>>>
>>> I think I know a little more now. I was able to bring up
>>> "loadusr classicladder --modslave" (I didn't know the rt component had
>>> to be loaded too). My netstat returned the same result above with
>>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>>> listed. I nmap both addresses and found port 9502 open on both, so it
>>> seems by default, "--modslave" will listen on all addresses (two in this
>>> case), with "all or any addresses" being called out as "0.0.0.0".
>>> http://en.wikipedia.org/wiki/0.0.0.0
>>>
>>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>>> previously. My guess is that as any ports above 1000 have lighter
>>> restrictions, maybe ports above a higher value are handled differently
>>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>>> do.
>>>
>>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>>
>>>
>> Actually, ports 1024 and below are considered "privileged" ports. Any
>> ports above that are considered "non-privileged" ports and are all
>> treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
>> port shows up.
>>
>> Mark
>>
>>
>> ------------------------------------------------------------------------------
>> Virtualization& Cloud Management Using Capacity Planning
>> Cloud computing makes use of virtualization - but cloud computing
>> also focuses on allowing computing to be delivered as a service.
>> http://www.accelacomm.com/jaw/sfnl/114/51521223/
>> _______________________________________________
>> Emc-users mailing list
>> Emc-***@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>>
>

[Peter Homann]

Hi Mark,

Oops, sorry I misunderstood the conversation.

Cheers,

Peter

On 29/02/2012 10:15 PM, Mark Wendt wrote:
> Peter,
>
> I was referring to Kirk's not seeing port 1502 after he assigned it in
> the loadusr statement, and how the OS handles ports above 1024.
>
> Mark
>
> On 02/29/2012 06:07 AM, Peter Homann wrote:
>> Hi,
>>
>> Port 502 is assigned to Modbus, so that's what slaves should use by default.
>>
>> Cheers,
>>
>>
>> Peter.
>>
>> On 29/02/2012 9:40 PM, Mark Wendt wrote:
>>
>>> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>>>
>>>> ... snip
>>>>
>>>> I think I know a little more now. I was able to bring up
>>>> "loadusr classicladder --modslave" (I didn't know the rt component had
>>>> to be loaded too). My netstat returned the same result above with
>>>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>>>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>>>> listed. I nmap both addresses and found port 9502 open on both, so it
>>>> seems by default, "--modslave" will listen on all addresses (two in this
>>>> case), with "all or any addresses" being called out as "0.0.0.0".
>>>> http://en.wikipedia.org/wiki/0.0.0.0
>>>>
>>>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>>>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>>>> previously. My guess is that as any ports above 1000 have lighter
>>>> restrictions, maybe ports above a higher value are handled differently
>>>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>>>> do.
>>>>
>>>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>>>
>>>>
>>> Actually, ports 1024 and below are considered "privileged" ports. Any
>>> ports above that are considered "non-privileged" ports and are all
>>> treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
>>> port shows up.
>>>
>>> Mark
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> Virtualization& Cloud Management Using Capacity Planning
>>> Cloud computing makes use of virtualization - but cloud computing
>>> also focuses on allowing computing to be delivered as a service.
>>> http://www.accelacomm.com/jaw/sfnl/114/51521223/
>>> _______________________________________________
>>> Emc-users mailing list
>>> Emc-***@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>>
>>>
>>
>
>
> ------------------------------------------------------------------------------
> Virtualization& Cloud Management Using Capacity Planning
> Cloud computing makes use of virtualization - but cloud computing
> also focuses on allowing computing to be delivered as a service.
> http://www.accelacomm.com/jaw/sfnl/114/51521223/
> _______________________________________________
> Emc-users mailing list
> Emc-***@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

--
-----------------------------------------------------------------------------
eStore: http://www.homanndesigns.com/store
Web : http://www.homanndesigns.com ModIO - Modbus Interface Unit
email : ***@homanndesigns.com DigiSpeed - Isolated 10Vdc I/F
Phone : [phone] TurboTaig - Taig Mill Upgrade board

[Mark Wendt]

Peter,

No problem. You brought up another tid bit to add to the conversation. ;-)

Mark

On 02/29/2012 06:17 AM, Peter Homann wrote:
> Hi Mark,
>
> Oops, sorry I misunderstood the conversation.
>
> Cheers,
>
> Peter
>
> On 29/02/2012 10:15 PM, Mark Wendt wrote:
>
>> Peter,
>>
>> I was referring to Kirk's not seeing port 1502 after he assigned it in
>> the loadusr statement, and how the OS handles ports above 1024.
>>
>> Mark
>>
>> On 02/29/2012 06:07 AM, Peter Homann wrote:
>>
>>> Hi,
>>>
>>> Port 502 is assigned to Modbus, so that's what slaves should use by default.
>>>
>>> Cheers,
>>>
>>>
>>> Peter.
>>>
>>> On 29/02/2012 9:40 PM, Mark Wendt wrote:
>>>
>>>
>>>> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>>>>
>>>>
>>>>> ... snip
>>>>>
>>>>> I think I know a little more now. I was able to bring up
>>>>> "loadusr classicladder --modslave" (I didn't know the rt component had
>>>>> to be loaded too). My netstat returned the same result above with
>>>>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>>>>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>>>>> listed. I nmap both addresses and found port 9502 open on both, so it
>>>>> seems by default, "--modslave" will listen on all addresses (two in this
>>>>> case), with "all or any addresses" being called out as "0.0.0.0".
>>>>> http://en.wikipedia.org/wiki/0.0.0.0
>>>>>
>>>>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>>>>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>>>>> previously. My guess is that as any ports above 1000 have lighter
>>>>> restrictions, maybe ports above a higher value are handled differently
>>>>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>>>>> do.
>>>>>
>>>>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>>>>
>>>>>
>>>>>
>>>> Actually, ports 1024 and below are considered "privileged" ports. Any
>>>> ports above that are considered "non-privileged" ports and are all
>>>> treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
>>>> port shows up.
>>>>
>>>> Mark
>>>>

[Peter Homann]

Hi Mark,

I currently have a prototype of ModIP, a TCP/IP modbus slave device that I'm
developing.

I think that Modbus over TCP provides an excellent robust interface for
external I/O devices. The biggest hurdle I'm trying to overcome at the moment
is the form factor. I've gone from a traditional PLC style to a miniature CPU
core board that plugs into various I/O motherboards, to a Arduino form factor,
to a daisy chain setup.

Still working on it. :)

Cheers,

Peter.


On 29/02/2012 10:24 PM, Mark Wendt wrote:
> Peter,
>
> No problem. You brought up another tid bit to add to the conversation. ;-)
>
> Mark
>
> On 02/29/2012 06:17 AM, Peter Homann wrote:
>> Hi Mark,
>>
>> Oops, sorry I misunderstood the conversation.
>>
>> Cheers,
>>
>> Peter
>>
>> On 29/02/2012 10:15 PM, Mark Wendt wrote:
>>
>>> Peter,
>>>
>>> I was referring to Kirk's not seeing port 1502 after he assigned it in
>>> the loadusr statement, and how the OS handles ports above 1024.
>>>
>>> Mark
>>>
>>> On 02/29/2012 06:07 AM, Peter Homann wrote:
>>>
>>>> Hi,
>>>>
>>>> Port 502 is assigned to Modbus, so that's what slaves should use by default.
>>>>
>>>> Cheers,
>>>>
>>>>
>>>> Peter.
>>>>
>>>> On 29/02/2012 9:40 PM, Mark Wendt wrote:
>>>>
>>>>
>>>>> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>>>>>
>>>>>
>>>>>> ... snip
>>>>>>
>>>>>> I think I know a little more now. I was able to bring up
>>>>>> "loadusr classicladder --modslave" (I didn't know the rt component had
>>>>>> to be loaded too). My netstat returned the same result above with
>>>>>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>>>>>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>>>>>> listed. I nmap both addresses and found port 9502 open on both, so it
>>>>>> seems by default, "--modslave" will listen on all addresses (two in this
>>>>>> case), with "all or any addresses" being called out as "0.0.0.0".
>>>>>> http://en.wikipedia.org/wiki/0.0.0.0
>>>>>>
>>>>>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>>>>>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>>>>>> previously. My guess is that as any ports above 1000 have lighter
>>>>>> restrictions, maybe ports above a higher value are handled differently
>>>>>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>>>>>> do.
>>>>>>
>>>>>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>>>>>
>>>>>>
>>>>>>
>>>>> Actually, ports 1024 and below are considered "privileged" ports. Any
>>>>> ports above that are considered "non-privileged" ports and are all
>>>>> treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
>>>>> port shows up.
>>>>>
>>>>> Mark
>>>>>
>
>
> ------------------------------------------------------------------------------
> Virtualization& Cloud Management Using Capacity Planning
> Cloud computing makes use of virtualization - but cloud computing
> also focuses on allowing computing to be delivered as a service.
> http://www.accelacomm.com/jaw/sfnl/114/51521223/
> _______________________________________________
> Emc-users mailing list
> Emc-***@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

--
-----------------------------------------------------------------------------
eStore: http://www.homanndesigns.com/store
Web : http://www.homanndesigns.com ModIO - Modbus Interface Unit
email : ***@homanndesigns.com DigiSpeed - Isolated 10Vdc I/F
Phone : [phone] TurboTaig - Taig Mill Upgrade board

[Mark Wendt]

Peter,

I'm really glad you hardware guys are around developing newer,
better, faster, stronger "stuff" for us. I did a minor in hardware when
studying for my Comp Sci degree, and have fiddled with electronics on
and off for a good many years, even being an avionics maintenance tech
in the USAF before getting my commission and wings. I'm starting to get
back into playing around with electronics (good lord there's so much
I've either forgotten over the years due to disuse of the brain in that
area, or so much new stuff has been developed in the mean time!).

Keep up the good work. Same goes for our good friends at Mesa and
Pico. We can never have too many hardware choices available!

Mark

On 02/29/2012 05:24 PM, Peter Homann wrote:
> Hi Mark,
>
> I currently have a prototype of ModIP, a TCP/IP modbus slave device that I'm
> developing.
>
> I think that Modbus over TCP provides an excellent robust interface for
> external I/O devices. The biggest hurdle I'm trying to overcome at the moment
> is the form factor. I've gone from a traditional PLC style to a miniature CPU
> core board that plugs into various I/O motherboards, to a Arduino form factor,
> to a daisy chain setup.
>
> Still working on it. :)
>
> Cheers,
>
> Peter.
>
>
> On 29/02/2012 10:24 PM, Mark Wendt wrote:
>
>> Peter,
>>
>> No problem. You brought up another tid bit to add to the conversation. ;-)
>>
>> Mark
>>
>> On 02/29/2012 06:17 AM, Peter Homann wrote:
>>
>>> Hi Mark,
>>>
>>> Oops, sorry I misunderstood the conversation.
>>>
>>> Cheers,
>>>
>>> Peter
>>>
>>> On 29/02/2012 10:15 PM, Mark Wendt wrote:
>>>
>>>
>>>> Peter,
>>>>
>>>> I was referring to Kirk's not seeing port 1502 after he assigned it in
>>>> the loadusr statement, and how the OS handles ports above 1024.
>>>>
>>>> Mark
>>>>
>>>> On 02/29/2012 06:07 AM, Peter Homann wrote:
>>>>
>>>>
>>>>> Hi,
>>>>>
>>>>> Port 502 is assigned to Modbus, so that's what slaves should use by default.
>>>>>
>>>>> Cheers,
>>>>>
>>>>>
>>>>> Peter.
>>>>>
>>>>> On 29/02/2012 9:40 PM, Mark Wendt wrote:
>>>>>
>>>>>
>>>>>
>>>>>> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> ... snip
>>>>>>>
>>>>>>> I think I know a little more now. I was able to bring up
>>>>>>> "loadusr classicladder --modslave" (I didn't know the rt component had
>>>>>>> to be loaded too). My netstat returned the same result above with
>>>>>>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>>>>>>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>>>>>>> listed. I nmap both addresses and found port 9502 open on both, so it
>>>>>>> seems by default, "--modslave" will listen on all addresses (two in this
>>>>>>> case), with "all or any addresses" being called out as "0.0.0.0".
>>>>>>> http://en.wikipedia.org/wiki/0.0.0.0
>>>>>>>
>>>>>>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>>>>>>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>>>>>>> previously. My guess is that as any ports above 1000 have lighter
>>>>>>> restrictions, maybe ports above a higher value are handled differently
>>>>>>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>>>>>>> do.
>>>>>>>
>>>>>>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> Actually, ports 1024 and below are considered "privileged" ports. Any
>>>>>> ports above that are considered "non-privileged" ports and are all
>>>>>> treated the same. Do a 'netstat -a | grep 1502' and see if the 1502
>>>>>> port shows up.
>>>>>>
>>>>>> Mark
>>>>>>
>>>>>>
>>
>> ------------------------------------------------------------------------------
>> Virtualization& Cloud Management Using Capacity Planning
>> Cloud computing makes use of virtualization - but cloud computing
>> also focuses on allowing computing to be delivered as a service.
>> http://www.accelacomm.com/jaw/sfnl/114/51521223/
>> _______________________________________________
>> Emc-users mailing list
>> Emc-***@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>>
>