Logix5 RIO Help

[uminded]

I am working on converting a Logix5 program (PLC5/20) into ControlLogix (L62). I was able to re-map the local IO easily enough but the old code has the PLC DH+ channel B as RIO and a old school HMI connected.

I looked around for a MSG or block transfer but I could not find anything. How do I see what/how the Logix5 was using the RIO and then on the Logix5000 how can I re-implement the same (1756-DHRIO)?

 

[Ken Roach]

Switch to the Usage view in the I/O data tables and you might find a continuous block of data that represented the HMI, or might more easily see the description tags for the discrete data being exchanged with it.

Check the RIO scanlist and use the process of elimination by accounting for the Remote I/O racks that you know are real-world I/O.

What sort of HMI is it ? A CRT-based PanelView 1200, or something else ?

Most HMIs use more data than the 8 words Input and 8 words Output that can be transferred by a full "Rack" of I/O memory, so they virtually always have Block Transfer Read or Write (BTR/BTW) instructions in the PLC-5.

RIO comms are always initiated by the PLC, as opposed to DH+ comms where the HMI device is a peer on the DH+ network and is the one that initiates all the read/write commands in the background of its memory data table comms driver.

 

[uminded]

It is a CRT based Siemens unit I believe.

How does a DH+ HMI read/write if the PLC5 is not initiating the transfer? At least RIO has a scan list to check.

The PLC5/20 has the plant DH+ network on Channel A and the HMI by itself on Channel B. The rack info says they are both set up as DH+. When viewed with RSLinx no nodes show up on either channel so I assume all messaging is local only.

I have a BTR/BTW for slot 5 which is the DeviceNet card status info but nothing else and no MSG instructions at all.

 

[Ken Moore]

If the HMI is on DH+, then it is a peer to the PLC, and it will initiate reads and writes to the PLC. There aren't any messages required.

Do you have the software/configuration of the Siemens unit? That would show you what tags the HMI is reading/writing.

Back in the day, many folks would move all HMI data in the PLC to one N:x file and have the HMI read write one large block of information to increase performance.


If you could add a PC to the Channel B network, you should see the PLC and the HMI as nodes in RSLinx.

 

[uminded]

Hmm, not having any code comments makes this very difficult... The Siemens HMI has never been touched, I doubt we have the software/dongles on hand. That's going to be fun to replace when it dies.

BTR/BTW are Rack 000, Group 5, Module 0. Data files N20/N21 both length 8.

The IO Config shows 1771-1AB (4 slot), 1 slot addressing. Local IO card config is just blank. The cards are:
[I16/O16][I16/O16][I16/O16][I16/O16][empty/1771-DNB]

Is the Above block transfers actually going to the HMI? I had assumed they were the cards status words from the 1771-DNB.