My application would be using a Plc-5 to poll 2 weigh scales via a Digi IAP serial port 1 and 2.
Im having problems getting the poll message (write) to occur with no errors. I’m getting "connection broken’ messages at the plc-5 using the same address locations refrenced in the above document.
What type of Plc-5 message instruction would I use to accomplish this ? How would I accomplish selecting which serial port ( of the digi ) to route the poll response read data ?
Current Plc-5 model and firmware revision - Plc-5/40E Series E Revision G
We don’t have a PLC5 & even buying one used on ebay with RSLogix5 license was looking like a $10K investment, so the IAP firmware just assumes (hopes) that the PLC5 creates what the ControlLogix, SLC5/05 and MicroLogix 1200/1500 PLC create when they claim to be using PLC5 commands. This is noted in the Release Notes (which of course no one reads
Make sure you’re trying the latest firmware “F” - “E” for sure rarely works with PLC5 due to a too generic an idea of the System Addressing for PLC5
DOIAP is handling the subfunctions 0x67/68 (the Typed Rd/Wr) and 0x00/01 (Word Range Rd/Wr), but then the PLC3 and PLC5 add different forms of layered addressing within this command - this is where the problems seem to come in. If you just use the DF1 specs details, you end up with something PLC5 won’t permit. Only a subset of what the spec implies is permitted is allowed in real life. After this fun, I see why the SLC5/MicroLogix team created the much more predictable typed rd/wr with 3 address fields. Too bad the PLC5 team is “above” supporting a lowly SLC500 command.
Anyway, worst case you can attach a Wireshark/Ethereal trace of your PLC5 request and I can look at the byte form being used.
I was having the same problem. I changed my communication command to “PLC-5 Typed Read to SLC”, and now it works fine. I am using a Series E / Rev. B processor.
