PLC 2/30 Support

Does the IAP support PLC 2/30 messages?

The IA parameter examples in the docs indicate

set ia master=1 errorresponse=on target=slc5

Does it support target=plc230 ?

I don’t know what DF1 commands a 2/30 uses. The “target-cif” is often called PLC2 & uses the Unprotected Read (cmd:0x01) and Unprotected Write (cmd:0x08). CIF is formally defined as “Common Interface File” and just implements a Modbus-style array of words.

You can only use CIF and SLC5 on firmware E/E1. The newer "F attempts to add PLC5 support; but unfortunately when I looked to buy a used PLC5E (with RSlogix 5, rack, power, etc), it was like a $12000 investment & it didn’t happen.

The Unprotected Bit-Write isn’t in there yet, in part because the CIF support in MicroLogix, SLC5, and ControlLogix is “diverse” enough to make me worry about bit masks on old PLC2, PLC3, and PLC5 that I cannot test on.

I found this web page that shows how an encoder works.

Yes, I need support for the “Unprotected Read” (cmd:0x01) and “Unprotected Write” (cmd:0x08). I’d like to communicate between a CLX and PLC-5E on Ethernet to the PLC/230 on RS-232 (DF1). Sounds like the serial side supports it, but does the Ethernet Side understand PLC-2 unprotected writes and reads?

Ok, I misunderstood the question. Sorry to confuse the issue. You are 100% safe if you are using a CLgx/PLC5E talking to a PLC2 via DF1. Since both your Master and Slave talk the same protocols (ie: they use CSP or DF1 or Ethernet/IP to move the same “PCCC messages”), the DOIAP does NOT modify or care about the messages. You just need to configure the MSG block to the correct target.

The DOIAP setting “target=slc5” ONLY affects a Modbus Master talking to a AB PLC. Since a Modbus master is NOT creating a “PCCC message”, the DOIAP must create a PCCC message by itself. For example, the DF1 spec includes like 8 different commands to “read N words”; but no PLC supports them all. So the DOIAP uses the “target=x” setting to select which of many commands to use.

So target=x is ignored in AB-to-AB situations.

Will work OK “peer-to-peer”?

Yes - peer-to-peer should work but I’ve never seen a PLC2 nor how they are programmed. Has any PLC2 user tried using a DOIAP or NetENI peer-to-peer with CLgx?

In the DOIAP define the PLC2 as a “Master” on the serial port. I’d suggest defining “slaves 0-1” as being the PLC2 on the serial port. Even though it is called a Master (or message source), DF1 Full-Duplex allows it to also be a destination & answer requests. This means RSLinx and other tools which default to DST=0 or 1 will work as you expect to access the PLC2.

Then you’ll need to define other slaves 2 to 254 as being remote CSP or Ethernet “slaves” at remote IP addresses. Then in the PLC2, whatever MSG block creates a DF1 request needs to have the appropriate LOCAL address entered to cause the DF1 message to the DOIAP to include a destination OTHER than 0 or 1. If the MSG block creates a DF1 messages with a destination of 0 or 1, the DOIAP configured as I suggest will just forward it back to the PLC2, who answers itself.

I’ve received my Digi IAP and am setting up a PLC 2/30 test. Are the protocol addresses in octal or decimal?

Everything is decimal (few but us “old-timers” even know what Octal is :slight_smile: - but older AB PLC and Data Highway keep reminding us).

  • Lynn