b'CPU : Item not available' Error

[KAYAUgurBerat]

Hello everyone, I want to change the values of the data blocks in the plc with the snap7 library. When I try this, I get the error shown below.

b'CPU : Item not available'
Traceback (most recent call last):
File "D:/Belgeler D/pythonProject/plcdeneme.py", line 10, in
plc_info = plc.get_cpu_info()
File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\site-packages\snap7\client.py", line 161, in get_cpu_info
check_error(result, context="client")
File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\site-packages\snap7\common.py", line 92, in check_error
raise Snap7Exception(error)
snap7.exceptions.Snap7Exception: b'CPU : Item not available'

Process finished with exit code 1

And this is my code:

import snap7
IP = "192.168.0.1"
RACK = 0
SLOT = 1

plc = snap7.client.Client()
plc.connect(IP,RACK,SLOT)

plc_info = plc.get_cpu_info()
print(f"adı: {plc_info.ModuleTypeName}")

state = plc.get_cpu_state()
print(f"State: {state}")

I made all the plc settings on Snap7's own site. What should I do to fix this problem? Thank you from n


ow

[swamper123]

This error can be legit...
What PLC do you got?

[KAYAUgurBerat]

I'm using S7-1200

[swamper123]

Sorry for the very late response. 😅

What I know is, that the 1200 and 1500 are not supporting all features.
I am sorry, but atm I haven't got a device on hand to verify this.

Since this doesn't seem to be an Python issue, you may ask at the snap7 directly.. Davide is very helpfull and just use his great work as a python-wrapper. :)

[ussefdesouky]

Its working on s7 1500 using PLCSIM Advance follow this link http://snap7.sourceforge.net/snap7_client.html#1200_1500

[swamper123]

The only suggestions I have left are:

• Firmware version on the machine (got a problem with wchars e.g.)
• still a snap7 thing (we receive a plausible message from snap7, perhaps problems are below? Right version installed?)
• the db is not global

Otherwise I can't help you atm. 😕

[rhyddid72]

me too, but i don't know how to slove that. If you go through, can you give me some tips. Thank you too much

[nikteliy]

Hi @rhyddid72

1. What PLC do you have?
2. Which function is causing the error?
   if you provide a network trace(captured with tcpdump or Wireshark), it will be easier to find the cause