AUMA FQM 05.1 - Execute Partial Valve Stroke Test (PVST)

A suitable FVST (Full Valve Stroke Test) or a suitable standard operation can replace
the PVST provided that the operation is signalled to a safety PLC and the safety
PLC is programmed as to control the following test sequence.
If safe end position feedback is required for both end positions, and if the diagnostic
coverage is to be used for the PVST, the PVST must be started from both end
positions. As an alternative, an FVST can be used for this test.
8.3. Execute Partial Valve Stroke Test (PVST)
The PVST procedure is identical for both safety functions.
There are two options for performing the PVST.
1. Performing the PVST using the standard function of AC .2:
In standard operation, the actuator is controlled via the standard PLC and AC .2.
For PVST, the operation sequence “end position -> no end position -> end po-
sition” is executed. During operation, the safety PLC monitors the following
states or events:
- When starting the PVST, is the actuator in the end position opposite the
safety end position (i.e. for fail safe CLOSE end position OPEN)? Monitor-
ing is made via safe end position feedback of FQM.
- Does the PVST start or is the safety PLC informed about the start of the
PVST via the standard PLC or the AC .2?
- Does the actuator unseat from the end position within the predefined PVST
operating time? Monitoring is made via safe end position feedback of FQM.
- Has the actuator returned to the initial end position once the action is
complete? Monitoring is made via safe end position feedback of FQM.
-
Has a fault been signalled via the output contact (FS module: FS
ready/FS failure NC) during PVST operating time?
2. Performing the PVST using the PVST function of AC .2:
If AC .2 actuator controls are configured with PVST input, this input can be used
for diagnostics of the safety-relevant part of actuator controls under certain
conditions.
Conditions and required settings:
- A digital input of actuator controls (galvanically separated from the other
inputs) is configured to the following value: Execute PVST (949)
- The safety PLC directly controls the PVST or will also receive the control
signal if the PVST input is controlled.
- The PVST is performed with the following operation mode setting: Para-
meter PVST operation mode M0889 = End position test
- The PVST may only be started from the end position opposite the safety
end position (i.e. for fail safe CLOSE end position OPEN).
-
PVST operating time M0890 parameter must be set to ensure that unseat-
ing from the end position will always be performed.
The safety PLC monitors the following states or events while the AC .2 actuator
controls execute the PVST.
- Is the actuator in the specified end position prior to the PVST? Monitoring
is made via safe end position feedback of FQM.
- Does the PVST start or is the safety PLC informed about the start of the
PVST via the standard PLC or the AC .2?
- Does the actuator unseat from the end position within the predefined PVST
operating time? Monitoring is made via safe end position feedback of FQM.
- Has the actuator returned to the initial end position once the action is
complete? Monitoring is made via safe end position feedback of FQM.
-
Has a fault been signalled via the output contact (FS module: FS
ready/FS failure NC) during PVST operating time?
The following applies to both procedures:The PVST was successful if the following
conditions are met:
●
At the beginning of the PVST, the actuator was in the specified end position.
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with non safety-related actuators Tests and maintenance