Elapsed-hour meter (C0178) and power-on time meter (C0179) exhibit deviation of 20 s/h (eliminated in ECS OPERATING SYSTEM as of V8.3, DPLC as of V8.3 and SPLC as of V8.0)

Eliminated as of:
ECS Application OPERATING SYSTEM as of V8.3
EVS93xx-EI (Servo PLC) as of V8.0
EVS93xx-ET (Servo PLC with technology function)  as of V8.0
EPL-10200 (Drive PLC) as of V8.3

Behaviour of the new version?
The deviation of the elapesed-hour meter and the power-on time meter (C0178, C0179) now amounts to a value considerably lower than 1s/h.

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Which products are affected?
EVS93xx-EI (Servo PLC)  <= V7.x
EVS93xx-ET (Servo PLC with technology function) <= V7.x
EPL-10200 (Drive PLC) <= V7.x
ECS Application OPERATING SYSTEM  <= V8.0

What happens?
Within the space of an hour, the values of the elapsed-hour meter (C0178) and those of the power-on time meter (C0179) deviate from the time that has actually elapsed by approx. 20 s.
C0178 not available in Drive PLC.

When does the problem occur?
The calculation of the operating hours and that of the power-on time by the PLC target system leads to the deviations described above.

Diagnostics options?
None

Short-term measures/recommendations?
The PLC application program can be used to detect the operating hours and the power-on time more precisely. You can set up a user task with an interval time of 1 s, for example. For the power-on time meter, you only have to declare one RETAIN variable (a variable that is safe against mains failure) that is incremented by 1 in every processing cycle within this task. The same applies for the elapsed-hour meter, except that the RETAIN variable is incremented on the basis of the controller enable.

Evaluation:
In practice, the elapsed-hour meter or the power-on time meter is not used for time-critical processes, as codes have to be used to gain access to the counters.

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