S7 PLC TIME OF DAY/datetime/time tag datatype issue

Forum|Forum|4 months ago
February 11, 2026
3 replies
140 views

Not able to read correct/exact data of siemens S7-300 PLC tags, datatype is TIME OF DAY/datetime/time.
Thingworx Kepware Server v6.16.217.0

Best answer by MKhatri

Greetings!!

ThingWorx Kepware Server v6.16.217.0 when reading Siemens S7‑300 time‑based datatypes such as:

TIME_OF_DAY (TOD)
DATE_AND_TIME (DT)
TIME

The Siemens S7 family uses non-standard binary and BCD‑encoded formats for time values,
which do not automatically map to Kepware’s OPC UA native Date/Time types.

Workaround Resolution:-
Convert Time Struct to STRING in the PLC
Read the Raw Bytes in Kepware and Decode in ThingWorx
Decode DATE_AND_TIME / TIME_OF_DAY Inside the PLC
Avoid mapping Siemens TIME/TOD/DT directly in Kepware

Regards,
Mohit

G

GC_11210517

Author

7-Bedrock

Please ignore:
Screenshot 2026-02-11 103023.png

M

MKhatri

Answer

Support

Greetings!!

ThingWorx Kepware Server v6.16.217.0 when reading Siemens S7‑300 time‑based datatypes such as:

TIME_OF_DAY (TOD)
DATE_AND_TIME (DT)
TIME

The Siemens S7 family uses non-standard binary and BCD‑encoded formats for time values,
which do not automatically map to Kepware’s OPC UA native Date/Time types.

Workaround Resolution:-
Convert Time Struct to STRING in the PLC
Read the Raw Bytes in Kepware and Decode in ThingWorx
Decode DATE_AND_TIME / TIME_OF_DAY Inside the PLC
Avoid mapping Siemens TIME/TOD/DT directly in Kepware

Regards,
Mohit

Sankalp Yadav

4-Participant

Hi,
I was facing the same issue earlier, but I was able to resolve it.
For the address DB360.DBD94 (DWord), instead of using it directly, try using DB360.DT94 with the String datatype. This allows you to correctly read the value as Date and Time.

Sankalp

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