i have modicon plc and emerson delta v dcs system. now we use RS-485 HALF DUPLEX cable for communication....

now give me the steps for comminication...
my question is.

we do the following steps

1. first we bring plc to run mode from pc.

2. then we remove the connector of pc and then attach the 8 pin min din connector of dcs wire..

IS IT CORRECT PROCEDURE????

but port 1 of the dcs does not blink so there must be problem....

tell me is there anything should be done from plc side. means any software should transfered or anything in configuration...

DUE TO THIS MY FINAL YR PROJECT IS STOPPED ...PLZ DO SEND REPLY... AS EARLY AS POSSIBLE..

 

Modbus is default communication for Modicon PLCs. You did not mention the Modicon Processor model or the programming tool that you are using (Modsoft, ProWorx, Concept, Unity).

You also did not mention the settings for Delta V?? I suspect that is your point of failure.

Thanks.

 

I believe your problem is you need a 232/485 converter. If you are moving the cable from the PC (232 port?) to the Delta V then you will need a converter.

Also you can check the Delta V termination pin outs from books online. I believe you will need handshaking jumpers on the modicon side, consult the documentation from the correct pin outs.
Stupid question, did you enable the Delta V port and set the comm parameters? Did you create an appropriate dataset tag to read values out of the PLC?

Did you choose 485 becuase of the distance or the multidrop capability
Good luck!

 

Thank you for your assistance...
The cable problem is now sorted out. We are currently studying PLC programming, our program is to transfer the field parameters to the DCS system (delta v). the field inputs are connected to the IO slots of the plc.

Is it necessary to write a program to store these input values in the plc registers and transfer these registers to the terminal port of the plc so that the DCS (serial card) can read the registers ...
if yes what would be the pattern of the program....