I am trying to use the Modbus master communication driver, but it does not seem to make the connection. I wanted to know if this feature is available in the free version or not?
Hi! all kinds of communication work with the free version, there is no limitation.
ModbusTCP can be a bit tricky but you can start by telling us which PLC are you trying to connect and which registers.
One known issue is that people tries to use the compact PLC 16 DIO which uses Byte variables to connect with the PLC, and that is not gonna work with ModbusTCP, because registers are Words or Bits.
I recommend you to try the system called “PLC Exercise 5: Training station - Handling unit” which is already set up for Modbus TCP communication and see if at least you get the connection with the PLC. Once that, depending on the PLC brand, you will need to fix the register numbers. Note that you cannot you addresses like QW0 or IW10… Just numbers.
Good luck!
Im using OpenPLC runtime to connect with sumumatik. I have two values in my PLC, 1 input with the address %IW0.0 and 1 output %QW0.0 both are of type BOOL. This PLC which the slave is working fine, but i’m not sure how to map it to the variables in simumatik.
Maybe this link can help you to find the proper registers for the addresses:
2.5 Modbus Addressing – Autonomy (autonomylogic.com)
But again, I recommend you to find the analog registers (16 bits) so you can use them with 16 port IO cards.
I assigned the address on the PLC by looking at the link you shared. But from where do I map I/O in simumatik?
I am trying the exercise 5 just to get the connection, but when I enable the gateway and start the emulation it says connection cannot be estabilished.
Dear Anjum, If you are still facing issues with OpenPLC and Modbus TCP, then kindly check lessons on OpenPLC in our academy. Here is the direct link: Simumatik | State of the Art Emulation