Micrologix 1100 to Micrologix 1100 ASCII message

Hey everybody,

I have two Micrologix 1100 connected via a serial cable between the two 9pin rs232 ports. I am trying to send a simple ASCII message from one ML1100 to the other and then to display it to the screen. I changed the channel 0 to an ASCII channel on both units and I am sending a 9 character message "SYSTEM ON" once ever second through the serial cable. I verified i am transmitting using hyper terminal. I can't seem to get the message to read. on the other ML1100. Anybody have any ideas. I would like to have the two controllers send several strings to each other and have one simply display the incoming messages on its LCD, maybe fire and output off the DN bit of the read function. Anybody have any ideas. Thanks in advance. The instructions i am looking at are ARD (ASCII Read) and AWT (ASCII Write). Any help would be appreciated, or if somebody has a better way using other commands i would be open to using that as well. Is it possible i need a null modem converter?

Thanks,
George

Just off the top of my head, I'd say double check the pin configuration on your serial cable, and the pinouts for the Micrologix 1100. I'd almost bet you need a null modem adapter.

MicroLogix 1100 serial ports are 8-pin, "Mini-DIN" type ports. If you have a 1761-CBL-PM02 or similar cable plugged into each one, you need both a gender changer and a null-modem adapter to connect them to one another.

I think that you can use the ordinary MSG command to transfer data from one MicroLogix to another; you can only send two String elements at a time (the message has to send all 82 possible characters) but it gives you the benefit of a built-in handshaking and data checksum.

And, of course, you can use the MSG command over Ethernet.

@ Ken

That's what i thought, I have a gender changer in between the mini connectors. Could you give me a general idea to use the MSG function over the Ethernet connection. Is it as simple as running a cable between the two ports and setting up the instruction? I have an ethernet cable.

Thanks for the replys guys

George

The MicroLogix 1100 Ethernet ports *should* be connectable just with an ordinary patch cable; in the worst case you need a "crossover" Ethernet cable.

You need to set IP addresses, of course, for each controller.

The MSG instruction requires both a Control block (MGx:y) and a Routing Table block (RIx:y), and is pretty straightforward to set up. I recommend triggering it with a repeating Timer.