Weird problem with slc 5/04 and panelview +

[Shiro485]

Hey Guys,
I have even contacted rockwell tech support about this, and they seem just as stumped as I am.

I have upgraded the panelview on an old machine, I have the panelview connected to the slc 5/04 through df1 serial connection.

To connect to the plc I used a pcmk cable, ended up having to make a few minor tweaks to the program but nothing extensive. Now my problem lies in that when I disconnect the pcmk cable from my computer, I lose communication on a bit n7:24 which is a screen status reporter so the plc knows which screen the hmi is on, to enabled certain logic pertaining to the screen.

With the pcmk cable plugged in it works fine, no issues. All the other communications appears to be ok, but that particular one. There has to be something messed up in the channel configuration or something, but I am downright stumped, has anyone experienced anything like this before?

Any help greatly appreciated.

 

[Ken Roach]

Do you have DF1/DH+ passthrough enabled on the SLC ? Maybe the PV+ is actually attempting to read data from your PC station on DH+. I can't explain why that would work for anything but basic connection status values, though.

Exactly what is the text of the error message you see onscreen ?

I wonder if the N7:24 word is just the most frequently read word, or the first in a group that is failing to be read, rather than being just one word that can't be read out of a data table.

Taken all together, these symptoms definitely are baffling. Let's troubleshoot from the beginning.

 

[Shiro485]

There is no error message,

To give a better idea, lets say I have a manual screen
in order to enable manual components, the plc has to acknowledge that the operator is indeed on the manual hmi screen.
a value of 1-8 is written to n7:24 representing which screen pv is on.

Again with pcmk plugged in everything works fine.
As soon as it is unplugged all other communications seem to work but the n7:24 screen status.

dh485 passthrough disabled bit s:34/0 = 0
df1 pass-thru enable bit s:34/5 = 0

 

[Ken Roach]

Is there any chance your 'screen status' logic also uses the DH+ active node status table (S:83 through S:86)?

Maybe the older HMI used the same node number as your 1784-PCMK/RSLinx station does now.

 

[Shiro485]

thats a very strong possibility. How can I confirm that? The logic in the program is just n7:24 is equ to then mov -> set of instructions depending on the screen status.

Is there something in rsview that I could check this with?

 

[Ken Roach]

I was expecting that the logic was "XIC S:83/2 EQU N7:24 1....." so that it wouldn't evaluate N7:24 unless the correct DH+ status bit was true.

Do a cross reference for S:83, 84, 85, and 86 to see if they are used anywhere in the RSLogix 500 program. I don't see a way that they would be used in the PV+ application.

Is the value of N7:24 always zero ? If you manually poke a nonzero value into N7:24, does it change back to zero ?

I've never seen a malfunction of the Global Connections feature that occurs like this.

 

[Shiro485]

ok ive discovered that a bit such as "manual control screen active" they have installed a latch or unlatch instruction

latch if the hmi reports that it is on that screen,

unlatch if it navigates away or if a comms ok bit is not true

comms ok being true depends on comms active s:1/7 dh+active nodes s:83/3 and dh+active nodes s:83/4.

Im a bit new so this a little alien to me. Im guessing, of course cause I cant see when I disconnect one or all of those dh+active nodes loses causing the comms ok to open up.

Thank you very much for your help

 

[Ken Roach]

The Status data table word S:83 bits /0 through /15 will represent the active node status of DH+ addresses 00 through 15.

The original programmer probably had a different DH+ address for the original HMI, or there was more than one HMI device connected.

You're on the right track; take the bit address that refers to your 1784-PCMK/RSLinx station out of the "Comms OK" logic.

 

[Shiro485]

Issue is Resolved.
Thank you very much for your help Ken,
Your awesome