S7-1200 I-Device Fault - Area length error...

System is an IPC547D running GRAPH in WinAC RTX. Six S7-1200 (CPU 1215C) running a little code for manual operations, but mostly running as I-devices. 12" Comfort panel. TIA13.

I can't write to PLC6 from GRAPH in the PC. Everything else in Seq1 is working. When I get to a block that writes to Q600.0, WinAC RTX goes into Stop with an error.

I was getting a double word error for address 600. I took out the command that wrote zeros to QD600. Now it doesn't crash until I try to turn on the VFDs in the mixer - Q600.0, Q600.1, etc. I was running with OB121, but took it out to see if I could get a clearer error message.

I've checked and rechecked. PLC 6 is configured the same as the other five working PLCs.
The expert from Siemens setup the first 5 PLCs as I-Devices. I setup the sixth. I-Device box is checked, addresses are correct. I've compared with working PLCs, but just can't find it.
What did I miss?

Overview of address gaps. PLC 6 has 602 - 16383. Others are only 100 Bytes. Q 0-99, Q 102-199, etc.

Fault from PC running GRAPH:

Area length error when writing
Q area, bit access, Access address: 600
FB number: 1
Module address: 2118
Requested OB: Programming error OB (OB121)
OB not found, or disabled, or cannot be started in the in the current operating mode

Are you sure you plugged in the right INs/OUTs when you set up the 6th PLC as an I-Device?

Yes:
PLC1 (working):
Q100..101 > I2..3
I100..101 < Q2..3

PLC6 (failing):
Q600..601 > I2..3
I600..601 < Q2..3

I'm not familiar with the S7-1200 range, but aren't there limits on the size of the process image?

I think limits are set by Profinet. Other PLCs have larger transfer areas.
PLC4 (working):
Q400..403 > I2..5
I400..403 < Q2..5
I404..427 < Q12..35 (Real numbers are 4 bytes each)

Process image not set to OB1-PI - Greyed Out

On the working PLCs, the "Process image" is set to OB1-PI.
On the failing PLC, the Process image box is greyed out. How do I set it to OB1-PI?

How big is the Process Image for WinAC? Perhaps it was set to only include the original CPU's, and the 6th 1200 is above the limit.

You should be able to change this setting in the HW config, and increase it above 600.

I don't see a Process Image or HW config in WinAC RTX.

I should have been more specific. The setting is not in the WinAC runtime control panel, the setting is in the device properties inside Step 7. I don't have portal open, so I'm not sure which heading it is under, but it is in the device configuration somewhere.

I'm using TIA13. That's part of the frustration. Everything I find online is for Step 7, or S7-300. Precious little examples with TIA anything. Ditto for S7-1200s.

Yes, the size of the proces image in the WinAC RTX project may be relevant. Maybe it is set to 512 bytes, which is why the 5th i-device is reachable.
If this is the explanation, then simply avoid access the IO bits directly. Instead transfer the IO image of the 6th PLC to/from an intermediary DB with SFC14/SFC15. Then use the bits in the intermediary Db instead of the direct IO addresses.
Btw, this is the proper way to transfer data to/from an i-device. Reserving data in the process image for this purpose is wasteful. So much for the "Siemens expert".

If the above is not the explanation ...

How did you setup the 6th PLC as i-Device ?
Have you generated a GSD file for this S7-1200 CPUs as i-devices, and imported this GS files in the WinAC RTX project in STEP7 classic ?
Post a screenshot of the HW Config in the WinAC RTX project.

Is the affected 6th PLC setup correctly with a unique Profinet name ?
Post a screenshot of the online Hardware Diagnostics for the WinAC RTX. (that will tell us if the IO Controller has even access to the 6th PLC).

mk42 said:

I should have been more specific. The setting is not in the WinAC runtime control panel, the setting is in the device properties inside Step 7. I don't have portal open, so I'm not sure which heading it is under, but it is in the device configuration somewhere.

Click to expand...

It would be in the WinAC RTX project in STEP7 Classic, not in TIA.
It is hidden under the "cycle/clock memory" tab.
My bad, I though that TIA didnt support WinAC RTX yet, it does.
You find the size of proces image settings under the Properties of the WinAC RTX controller at General ... Cycle.
Default is 512 bytes, so it does look like it is the explanation.

That was It!!!

That was it!
I can't thank you enough. I've been reading manuals all day.

I set input and output for 768, to stay with multiples of 128. Does that matter?

Overview of address gaps. PLC 6 has 602 - 16383. Others are only 100 Bytes. Q 0-99, Q 102-199, etc.

Click to expand...

I didnt notice that until now. Seriously you use the addresses 602-16383 ?

keithkyll said:

That was it!
I can't thank you enough. I've been reading manuals all day.

I set input and output for 768, to stay with multiples of 128. Does that matter?

Click to expand...

No