After conversion (STEP 7 Basic V10.5 to STEP 7 V11) of S7-1200 projects with timers, the "RU" tag ("RUNNING" in STEP 7 Basic V10.5) can no longer be accessed in the instance data block of the timer.
When you compile your converted S7-1200 project, you get the following error message when you use this tag:
"Accessing private and internal tags is not permitted."
Using the interconnection of the other Boolean tags of the timer instance data block you can simulate the "RU" "Running" bit as below, depending on the type of timer:
||In the case of the "Generate pulse" timer TP the instance DB tag "Q" (output) corresponds to the "Running" bit.
|In the case of the TON "ON delay" and TONR "Latching ON delay" timers, the "Running" bit results from a link of the instance DB tags "IN" (input) and "Q" as opener.
||In the case of the TOF "OFF delay" timer, the "Running" bit results from a link of the instance DB tags "IN" (input) as opener and "Q".
The pictures in this FAQ were created with STEP 7 V11.
Always use the combination from the instance block tags (and not a buffering of them), because in the case of asynchronous querying the buffer does not necessarily reflect the current state.