Samson 4785, Монтаж и эксплуатация

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Air leakage in pneumatic system
The actuator must stall for a few seconds when the duty cycle is being determined initially. This time is used to check the
pneumatic system for leaks. If the control valve moves more than 9.3 % from its resting position in 7 seconds, the relevant
message is issued and additionally, an initialization warning is indicated. Warning, initialization is not aborted.
Possible sources of error:
– Actuator untight
– Signal pressure connection untight
Initialization status: determining the mechanical stops
When determining the mechanical stops, the initialization routine recognizes the spring action and zero by completely
venting and filling the actuator. In addition, the routine checks whether the positioner can move through 100 % rated
travel/nominal angle.
Initialization status: determining the minimum transit times
Transit time determination measures the time required by the valve to pass through the rated travel/nominal angle from
0 % to 100 % and vice versa.
Initialization aborted through activation of forced venting function
If the implemented forced venting option is activated, the initialization process is aborted. For the implemented forced
venting option, a voltage between 6 and 24 V DC must be applied to ter81 and –82.
Zero point error
The determined zero point exceeds the permissible tolerance limit of max.
±
5 % around the internal absolute value for the
detection of measured values. Initialization is aborted.
To eliminate this error, adjust mechanical zero as described in section 4.4.1.
The yellow pointer of the displacement sensor must then be approximately aligned with the white marking on the cover
plate.
Proportional band restricted too much
Even the smallest permissible pulses still cause too large changes in travel. Initialization is aborted.
Possible sources of error:
−
Supply pressure too high
− Missing signal pressure throttle for actuators with small volumes
−
Error in the mechanics, particularly with attachment according to IEC 60534-6 (NAMUR)
− In case a booster valve has been mounted for large volume actuators, the bypass should be opened further.
Successful
Initialization has been successfully completed without error.
EB 8382-2 EN
71
Messages and diagnosis