MSG Instruction for Micrologix 1000s and SLC 5/02

I'm trying to send a network bit across a DH485 network to 2 micrologix 1000s from a micrologix 1000. The goal is to send the same network bit to 2 plcs. Can 1 MSG instruction send to both plcs or do I need to have an individual MSG instruction per plc for the same bit? Do the receiving plcs need a MSG instruction as well? Im posting the code we are experimenting testing as well as the setup for the MSG block. We tried sending the same network bit to both plcs with an MSG instruction for each plc, but the first MSG block kept overwriting the 2nd block.

Does anyone have any ideas or help?

Thanks
Brad

First if you are going to write data from the SLC5/02 to the ML1000's you will need two message instruction in the SLC. In their setup you program the node address you want to send the data to. You don't need a message instruction in the ML1000's.

You can read data from your SLC by programming a message instruction in each ML1000.
If you do this you would not need a message instruction in the SLC.

My preference is to read not write.

Mickey, thank you for your reply. I will definitely implement this and see how it works - it looks like it will be pretty easy. Quick question - this will be the same for the mircologix 1200 and 1500 - to use the same method?

Thanks again,
Brad

Quick question - this will be the same for the mircologix 1200 and 1500 - to use the same method?

Click to expand...

Yes, take a look at the online instruction help for the message instruction. There are some differences between the SLC5/02/ML1000 and the ML1200/ML1500.

ok, thank you for you response. I will check into it.
Thanks,
Brad

Mickey,
We tried reading from 2 mircologix 1000s. We set an input true in 1 plc but the other 2 plcs didn't see the change over the network.

Post your programs if you can. The .rss files for all processors, zip them first.

Someone may be able to spot something.

How are they physically connected to each other? Described the network connections in detail or a drawing.

Here is the code - we tried it by reading the network bits from the 1 plc to the other 2. I also have code for writing from the 1 plc to the others. It may just be a setting in the msg that we are not configuring correctly by I don't know.

Thanks for the help,
Brad

Are Larry and Moe two different ML1000 units? Some of the files have the channel set up for DF1 @ 9600, and others have it set for DH485.

Do you have the file(s) for the 5/02?

Also, it appears to have worked once. You have a DN bit set in one of the messages. It appears you are missing some logic to re-trigger the MSGs, unless the start/stop logic is intended to do that and later be replaced but something that repeats.

The MSG rung needs a false to true transition in order to repeat.

EDIT: It would help if you can list all the devices on the DH485 network along with their node numbers. Even better if you can add the details of how they're connected.

Thank you for your responses. I know its been a couple of days but I was not able to work on the project until today. I have some new code that we had tried out but we are still having some issues with the MSG block.

The Network:
Node
00 Workstation
01 SLC 5/02
02 PV550
03 Micrologix 1200
04 Micrologix 1200
05 Micrologix 1500

The new code I am posting is for the SLC 5/02 titled ControlPLC, and for the Micrologix 1200 on node 04, titled BACKPLC.

In the ControlPLC code, we are trying to send 3 messages out - 2 of the messages are based on 1 PV550 output and another message is controlled by another PV550 output. We are using write messages because using read message instructions in just the BACKPLC code did not work.

I have a feeling we are just not configuring the MSG instructions correctly.

Also, is it possible to use 1 bit to control parallel MSG instructions? Can we send the same network bit to multiple plcs on the DH485 network or do we have to daisy chain the MSG instructions - send the a bit to the plc on node 04 and then the same bit from the plc on node 4 to the plc on node 05 for instinct?

Thanks,
Brad

In the files you posted the message instructions are trying to send one of the message instructions control words. These words are used by the instruction for status and other info associated with the message instruction. What word has the bit you want to send to the ML1200?

The message instructions are trying to send data to node 5, but the ML1200 is configured for node 3.
You will also have to have the data files setup in the receiving PLC.

Message instructions as stated above need a false to true transition to work. It is best to sequence thru multiple instruction one at a time.

If you can tell us exactly what word you are trying to send and what word you want it sent to someone can give you an example.