PLC emulation with Citect SCADA

Hi.

I'm using a citect application running on a computer connected to a plc (tsx premium) with modbus protocol.

To maintain and devellop my application, i want to use a citect application running on an other computer to emulate my plc instead of the real one (for security reasons).
Is it possible?

I had successfully implemented the communication with the real PLC. My application can resquest variables to the plc using the modbus adressing (i.e. 10011 for a bit).

(This is an example, not the real case)
My application needs to read and write the bits in the PLC from 10001 to 10100. How can I create those variables in my PLC emulator and make it working?

Thank you for help.

Rather than use another PC with Citect to simulate your PLC why not a modbus simulator ? I have used on in the past called Modsim32.exe. I have set this software up on a Virtual PC and then from another Virtual PC running Citect I could test my Citect application. Modsim32 will run logic for you but does allow you to turn Modbus bits ON/OFF and write Data into Registers that can be read from another location.

Thank you for your answer.
I already tried some plc simulators like Modsim or Mod_RSSim. But the problem still remains. If I only have a couple of bits or registers to change, it would be much easier and a good solution. I need to add code to my application to correctly fulfill the PLC emulation.

In the plc IO device set the memory flag (it is a selection on the io device form). When a device is in memory mode it will not poll the plc and all the tags will be able to be written to within Citect

Also UnityPro comes complete with a plc simulator, so this may be another option if you are already using UnityPro to program your plc