Cross Talking

[tvsteevie 1]

I've tried to find this here but there is sooo much information I can't seem to nail it down. How do you get an input from an ML1200 into the logic of a SLC 5/03, and vise-versa ? I need to see the input from the ML in several rungs of the program running in the SLC, and I need to see some outputs from the SLC in the ML1200 . Both are connected through DH485.

[Ken Moore 23]

Map the desired inputs or outputs to integer addresses, then use the message instruction MSG to message the integer data back and forth between the two processors. There are a lot of folks that will tell you that writes are better than reads, but I prefer to use a read instruction, that way you can comment on where the data comes from and what it's for. So have a read MSG in the SLC to get the data from the ML1200, and have a read MSG in the ML1200 to get data from the SLC.

[CTSoft 0]

Assuming your SLC node =2 , ML1200 node = 4. On ML1200, map all the input bits you want into Integer words. Example : Xic I:0/0 OTE N101:0/0 , xic I:0/1 OTE N101:0/1 ...... and so on. SOR XIC S:4/6 MSG MG9:0 Read 500CPU Local 0 2 N100:0 N100:0 10 5 132 EOR Paste this logic into your ladder. This is to read in the output status from SLC unit. On SLC, Assume your output modules located at slot 2 and 3. Example : COP #O:2.0 #N100:0 2 SOR XIC S:4/6 MSG READ 500CPU LOCAL N9:0 1 4 N101:0 N101:0 10 5 0 EOR Paste this logic into your ladder. This is to read in the INPUT status from ML1200 unit. Now, you can test out,by giving I:0/0 ON. Check SLC data file N101:0/0, it should received ON too. Hope this information will help you.

[tvsteevie 1]

Where would I find instruction for mapping inputs from one plc to be used in another plc on the same DH485 network. I have read the MSG instruction until my eyes bled but I still don't get it ! Edited 31 Jan 2007 by tvsteevie

[panic mode 246]

MSG instruction is just like COP... The only difference is that works over network so source and destination are in different PLCs. If you want to send status of inputs on PLC1 to PLC2 so program on PLC2 can use them, all you need to do is pack everything you want from PLC1 (could be inputs, outputs, memory bits, anything) into some temporary storage (N file such as N100) which is still on PLC1. Make sure that PLC2 has file big enough to accomodate the stuff you want to bring over from the PLC1. Let's call it N101. Keep executing read message instruction from PLC2 and tell it to copy memory from PLC1::N100 and paste it into PLC2::N101. Now if any of the N100 bits that you read from PLC1 is set, you should be able to see copy of it in N101 on your PLC2. PLC2 will not know what this really is (input, output or whatever), you need to arrange (and know) what parts of N100 will be inputs, because for those, program on PLC2 will be using N101:X/Y (PLC2 memory address) instead of I:X/Y (Physical input on PLC1).