Reading a Optimized DB

[gaurav041089]

Hello,
Testing the S7commplus on following
PLC: 1212 Ver 4.0
PUT/GET is enabled.
DB is optimized. (Hence using s7commplus instead of snap7)

Using following code
from s7commplus import Client

PLC Connection Details (S7CommPlus does not take rack/slot)

PLC_IP = "192.4.0.102"

def read_optimized_symbol():
client = Client()

try:
print(f"Connecting via S7CommPlus to PLC at {PLC_IP}...")
# Pass only the IP address
client.connect(PLC_IP)

print("Connected! Browsing symbols to find DB3 and 'Sts_run_m'...")

# Browse the symbol tree to inspect available data blocks and tags
symbols = client.browse()
for symbol in symbols:
  print(symbol)

except Exception as e:
print(f"An error occurred: {e}")

finally:
try:
client.disconnect()
print("\nDisconnected from PLC.")
except Exception:
pass

if name == "main":
read_optimized_symbol()

IDLE Output
==== RESTART: C:\Users\Gaurav S Mithari\Desktop\Finolex\Cutter\1212Test5.py ====
Connecting via S7CommPlus to PLC at 192.4.0.102...
CreateObject returned non-zero 0xE022BD000190FF7A; continuing to parse the returned session data
PLC did not provide a usable ServerSessionVersion attribute; S7CommPlus session setup cannot continue. No automatic fallback to the classic PUT/GET protocol is performed.
Connected! Browsing symbols to find DB3 and 'Sts_run_m'...

Disconnected from PLC.

Wireshark dump between PLC and TIA Portal

1212TIA_to_PLC.zip

[gijzelaerr]

There are two separate findings here. First, reporting "Connected!" after session setup failed is a client bug. #861 makes connect() raise and clears the intermediate connection/authentication state when ServerSessionVersion is missing or setup is rejected. This fixes the false success indication; it does not yet explain your CreateObject rejection.

I inspected the attached capture. It shows a successful TIA CreateObject and SetupSession exchange, but does not contain the failing Python connection. Please capture that Python attempt against the same unchanged CPU, with full debug logging and the exact installed commit/version, so we can compare the requests and responses directly.

Please also confirm the CPU's actual firmware version: the TIA CreateObject response in this capture identifies V4.2, whereas the report says V4.0. The distinction matters when comparing session negotiation. No automatic classic PUT/GET fallback should be used for this optimized DB.