radio modem

i can't remember how to do ladder logic for simple transfer of data on a modem. I am receiving a 4-20mA signal into a Modicon Momentum plc with a analog module 170 AMM 090 which accepts 4-20mA directly. So all I need to do is accept the analog signal on a 3XXXX register then transfer it to a 4XXXX holding register. Also I was asked to give a status of both the plc and modem to be sent to receiver. Now some how my modem has to send this info.

Brain ****!!!

Good one....

kelly said:

i can't remember how to do ladder logic....Brain ****!!!

Click to expand...

I couldn't pass up that one.

If your modem is always live and connected to the PLC, it is treated by the PLC just like a hardwired serial connection. Use the same read/write commands you would use for direct serial connection. If your radio modem has a key function, use an output on the PLC to turn on the modem transmit a fraction of a second before you enable the write.

A Modicon 984 Ladder Logic command for transferring data from one register to another is BLKM (block move)