Modbus Demo Box...Software equivolent??

Hi,

Can anyone tell me if there is modbus demo box simulator software?

We used a modbus demo box in a SCADA lab, connected to serial / COM1 on the PC connecting it to NI Lookout.

Is there an equivolent software simulator available?

Thanks,
James.

It had a few switches, pot's output led's etc on it that lit up when interfaced with lookout...

http://www.modbustools.com/modbus_slave.asp

modbus slave will do what you want but you would have to change the values in the software.

Here are some no-cost tools:

http://modrssim.sourceforge.net/ (flexible Modbus slave)
http://www.azeotech.com/index.php (Modbus master app is free with demo install)
http://deltamotion.com/files/tcpdemo.zip (great for measuring round trip time)
http://update.redlion.net/c3/update/setup.exe (15 minutes of runtime from emulator)

And of course there are others...

Here's another

http://www.google.com/search?q=mods...s=org.mozilla:en-US:official&client=firefox-a

Anyone know how to set these programs up so that you can turn a register on or off in the simulator and link to the register directly in lookout 6.5?

I don't have a PLC....

Presumably Lookout 5 is an HMI program, which will act as a Modbus master.

The programs that various contributors listed above will presumably function as a Modbus slave when installed in a Windows environment.

Since Modbus slaves are not integral to the PC on which a Modbus master runs, I doubt the Modbus slave software is addressable by the Modbus master when the slave software is installed on the same PC as the Modbus master, which is what you seem to be asking for.

I believe that you will need to install the Modbus slave software on a separate Windows PC and then make the Modbus connection from the Lookout 5/PC master to the Modbus Slave PC over whichever connection makes sense, serial or ethernet.

The Modbus slave software on a separate PC is emulating the Modbus slave PLC.

Hello,

> I doubt the Modbus slave software...

PeakHMI supports concurrent MODBUS RTU/TCP master and slave. For serial(RTU) you just need to use 2 or more serial ports. If a master and RS485 then one port for up to the links physical limit; RS232 1 port per device. If a slave then 1 serial port per slave ID. Though we could add support for multiple IDs per serial port.

For TCP, as a master you can have as many connections as are needed. If you need to use only one socket we have a single socket mode. For slaves, unlimited.


Good luck,

Mark
http://www.peakhmi.com/

Some comments:

1. Master and slave on same PC over a network connection should work fine. Use 'localhost' or 127.0.0.1 as destination, or even the local IP. There is no requirement that the data actually hit the ethernet wire with the loopback interface.
2. With serial, as already mentioned, would require two serial ports, but will still work. I usually do this with two USB/RS232 adapters, or some vendors sell multi-port USB/serial adapters so would only need one of these.
3. The Redlion emulator actually picks up a different IP address than the host it is running on so I think it must bridge in code, so in this case, you wouldn't use localhost but rather the configured IP.

If this is a quick test to be sure everything works correctly before deployment then the free tools listed above are useful. But if this is a customer demo or if I wanted to be fancy to show upper management, I would probably spend some money on more professional software designed to do what you are asking - it looks like peakhmi would do it. For instance, I wouldn't showcase our newest technology by using someone else's Modbus slave emulator that is branded and only works for 15 minutes.

Mark,

Are you saying that PeakHMI's Modbus master can poll PeakHMI's (concurrent) slave on the same PC?

How does that work?

Through serial or ethernet ports? Master on one port? Slave on another?

Or some sort of internal bridging?

Dan

Hello,

>Are you saying that PeakHMI's Modbus master can poll PeakHMI's (concurrent) slave on the same PC?

Yes

> How does that work?

Very well.

PeakHMI has what we call 'ports'. A port is a connection to a 'device' or entity. For MODBUS the connection can be serial or TCP/IP. For example a Master RTU on com port 1 and a Slave RTU on com port 2.

When a 'tag' is created you specify a 'port' and a source address. If you had tag 1 as Master RTU 400001 and tag 2 as Slave RTU 400001 they would point at different memory.

The Master RTU would be reading the data from an external device (external to it) and placing the data in tag 1. The slave emulates all the MODBUS address space and the tags assigned to the port use the internal memory.

You could assign tag 1 to tag 2 or vice a versa. (The master or slave might write over it afterwards.)

Ciao,

Mark
http://www.peakhmi.com/

Mark- said:

The Master RTU would be reading the data from an external device (external to it) and placing the data in tag 1. The slave emulates all the MODBUS address space and the tags assigned to the port use the internal memory.

Click to expand...

Thank you for that explanation, Mark.

Can the Master RTU on port x at COM1 do a 03 holding register 'read' of slave RTU register 40001 on port y at COM 2 (on the same PC) [arbitrary COM assignations for example] without physically wiring COM 1 to COM 2?

Dan

Hello,

>Can the Master RTU on port x...

Yes, using a virtual serial port like: http://com0com.sourceforge.net/.

While I have never used this one I have read others comments that it works fine. I am sure other virtual serial ports exists, I have read about them for years.

Of course, switching to TCP would not require any additional software or hardware.

In PeakHMI the tag holds a attribute which is the port name. Switching a tag from one port to another is very easy.

Ciao,

Mark
http://www.peakhmi.com/

Thanks lads.