Identifying Known Ethernet IP connections

[macg 0]

I'm sure many of you remember AB's DH+ communications.  I have a system that is variable or configurable.  I have a customer that paints large parts automatically.  The coating process dictates what type of auxiliary equipment is required.  I wrote a program years ago that would determine what subroutines to run depending on what DH+ stations that reported in when the processor was powered up.  The program new by what was attached the type of system it was and controlled that particular process.  Thank goodness DH+ is for the most part in the past.

This same customer wants to upgrade many of the PLC-5's running this code to a ControlLogix.  I'm struggling how to create the same type of setup of determining what equipment is attached be looking for the IP address.  Has anyone done this or have ideas on how to find a known IP address on a network?  The IP addresses are all fixed.

[Joe E. 259]

Are the auxiliaries all controlled by the main PLC as I/O devices or are they independent PLCs?

If they're independent PLCs, do they communicate with the main PLC over Ethernet/IP?

If the main PLC has the auxiliary machines in its I/O tree (whether as I/O devices or as other PLCs it's talking to), you can use a GSV instruction to check the "connected" status of that device.

The return value is a number that explains the status of the module connection. It's shown here in decimal, but the help file explains the results in HEX:

In this example, 24576d = 6000h, which means that module is inhibited (the drive isn't actually installed yet in this system). If it were connected and running, it would be 16384d = 4000h.

 

[BobLfoot 301]

macg - I have some thoughts on your situation but may be a little long winded in explaining,  It is one of my personal pet peeves that System Integrators and even Plant Support Personnel don't do a good job of handshake between networked plcs.  Were I solving your problem I would set up a network of compact and control logix processors using the produced/consumed data model.  Each Station would have an ethernet card/port connecting to the station IP network of 192.168.C.X and would also have an Ethernet Card?port connecting to the System IP network of 172.B.C.X.  The System network would use Produce consume tags and have logic that as long as the handshake bit was freshly passing between Control Central and Station that Stations Program was scanned.  A station which became unresponseive after being recognized would execute a fault block of logic.  A station not present after power up delay would be considered not attached.  Hope I was clear enough.

[macg 0]

Thank you BobLfoot & Joe E.  I know I posted this back in December.  Christmas shutdowns had us all very busy.  There is only one Control Logix processor.  The various other components that may or may not be attached to the system will all be blocks of remote I/O.  We are mimicking the old PLC-5 setup for the customer.