Scada

[scott]

Using NI Lookout, how are you setting your drivers up?
I want to use com 1 for scada. I only need to pull status form one plc no control is needed.

[support]

Please download a Lookout test file that works with the M-series PLC from the following link:

 http://www.tri-plc.com/applications/testmodbus.zip

unzip the files into your lookout folder and open up the testmodbus.lks

[scott]

What is the configuration of the plc? What plc programming is needed?

[support]

The PLC standard serial port configuration is 38,400, 8,1,n.

There is no special programming required. The MODBUS protocol work transparently off the PLC. Your program need not even be aware that there is a SCADA constantly queries the PLC for data.

[Scott H]

What directory will modbus.ini go into? I still can?t establish communication with the PLC.
I am running three slaves (modbus ascii) on the 485 port (1,2,3) and wish to interrogate the master (0) for status information on the RS232 port. Is this possible?

[support]

modbus.ini should go into the Lookout's directory.

It is possible for a PLC to be master to another 3 slaves via RS485, and its RS232 port can still be connected to another master such as SCADA.  In that case the master PLC's become a slave to the SCADA master on its RS232 port.

However, you cannot use an ID=0 for any modbus slave because ID=00 is reserved for MODBUS BROADCAST command only. So in this case you must define the ID for your master PLC to be anything other than zero.

Our sample Lookout file in the "testmodbus.zip" assume that the ID of the slave = 01. I suggest you should try to get a successful connection using the a PLC with ID=01 first before venturing into more complex configuration.