Hi,
I'm using Sharp7 in my project with a PLC S7-1500.
Sometimes (it doesn't happen every time) the information doesn't arrive to the PLC variables.
I'm using the function "DBWrite" to write a few values (120 bytes) but sometimes the writing result is true, but on the PLC side
the values haven't changed from the previous value.
Has it ever happened before to anyone?
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Every so often a write command seems to not be processed by the PLC. Regardless of single write of multi var write.
Only happens to S7-1500. Tried with S7-1200 and this PLC does not experience this problem. Also tried different firmware versions of S7-1500. Wireshark shows the write command, and it is also confirmed by the PLC with a success, however, the actual value in the PLC is not changed.
Any solution to this?
EDIT:
Ok, solution found.. I used the data I was writing to as a INOUT in the PLC software...
Last edit: henkauto 2022-07-13
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that's not a funny thing :-(
I discovered (I guess) a bug into the S71500 Firmware (only 1500, neither 1200 nor S73XX/4XX)
The write command returns Error 0, I analyzed the telegram and it was ok, but the variable is not written.
Only write operations are affected.
I solved in this way:
1 - The DB must be unoptimized (and that was known).
2 - Il the variable that we write is passed directly or into a struct to a FB/FC, also that FB/FC must be unoptimized
Seems that there is something wrong to the lock/unlock mechanism
Let me know
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
I'm using Sharp7 in my project with a PLC S7-1500.
Sometimes (it doesn't happen every time) the information doesn't arrive to the PLC variables.
I'm using the function "DBWrite" to write a few values (120 bytes) but sometimes the writing result is true, but on the PLC side
the values haven't changed from the previous value.
Has it ever happened before to anyone?
Same thing here.
Every so often a write command seems to not be processed by the PLC. Regardless of single write of multi var write.
Only happens to S7-1500. Tried with S7-1200 and this PLC does not experience this problem. Also tried different firmware versions of S7-1500. Wireshark shows the write command, and it is also confirmed by the PLC with a success, however, the actual value in the PLC is not changed.
Any solution to this?
EDIT:
Ok, solution found.. I used the data I was writing to as a INOUT in the PLC software...
Last edit: henkauto 2022-07-13
that's not a funny thing :-(
I discovered (I guess) a bug into the S71500 Firmware (only 1500, neither 1200 nor S73XX/4XX)
The write command returns Error 0, I analyzed the telegram and it was ok, but the variable is not written.
Only write operations are affected.
I solved in this way:
1 - The DB must be unoptimized (and that was known).
2 - Il the variable that we write is passed directly or into a struct to a FB/FC, also that FB/FC must be unoptimized
Seems that there is something wrong to the lock/unlock mechanism
Let me know
I didn't realize I declared the struct I was writing to as an INOUT variable in the application .. solved the problem..