PLC5 by DH+

I have a PLC5 processor that I cannot talk to. I am trying to talk via DH+, and when I plug into another processor which is running, I immediately see the processor. When I try to browse for the one in question, however, I never see it. This processor has no memory in it, as it was powered down, and now when powered up, the processor light is red, and so is the battery light. Can I communicate with this processor when there is nothing in it? I am assuming the processor light is on because there is nothing in it, or does this mean that the processor has a problem. This is a spare that I am trying to use as a bench PLC to troubleshoot a panelview project that I have. Thanks in advance.

Russ

P.S. This PLC is not currently talking to anything else, therefore the DH+ resistor is not installed. Just wondering if this could be my problem.

Hello Russ,

The terminating resistors are probably not the problem if the controllers are close together and you're close to them. Furthermore you indicate that you see the dead controller in the node table on the working PLC-5 which means that the processor controlling DH+ is working.

The red light means that memory is invalid. If this is an NP5, try connecting to it RS-232 and initializing. Once the red light goes away we will improve our trouble-shooting capability.

Once initialized you'll be able to communicate to the default data table areas that are created when you initialize a PLC-5.

Fill us in on the status of the system as you progress.

Good Luck,

(8{)} ( .)

(Yosi)

DH+ Network?

russrmartin

If this test PLC5 processor is on an existing DH+ network the problem could be the node address is the same as an existing PLC processor.

Dan

If this test PLC5 processor is on an existing DH+ network the problem could be the node address is the same as an existing PLC processor.

Click to expand...

Or, the same node as the programming terminal.

Or both the processor channels are configured for different baud rates, say one at 57.6k and the other for 230.4k.

You don't mention the specific model of PLc-5, but regardless, channel 1A is default DH+. If the LED for that channel is blinking intermittantly, then the processor is not seeing the DH+ network. If it's solid, it does see the network and you have some other problem, such as a duplicate node number. If you already have a node 01 on this network, it might be your problem as (as I remember) a default processor has DH+ address 01.

If that's the case, then disconnect the processor from the network and try to get online directly, change the node number to something currently unused and then put it back onto the network.

getting back

Sorry it took so long to get back. I did have a faulty processor. Could not connect to it in any way. I found another one on a shelf and connected to it both serially and by DH+ without a problem. Thanks to all for the suggestions.

Russ