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8.4.5 Check Safe ESD reaction to “Forced limit seating in end position” (limit evaluation) – for actuators with
electromechanical control unit
This test is required for the following versions or configurations:
• Actuator with electromechanical control unit(MWG.2)
• One of the following safety functions:
− Safe ESD function “Safe CLOSING” (Safe ESD in direction CLOSE)
− Safe ESD function “Safe OPENING” (Safe ESD in direction OPEN)
• Configuration of “SIL seating”
= “Forced limit seating in end position”
(safety operation is stopped by limit switch tripping)
During the test, the reaction of the Safe ESD function to limit switch tripping during safety
operation is checked.
During Safe ESD operation, the actuator has to stop when reaching the position set via limit
switching.
8.4.6 Safe ESD reaction to “Forced limit seating in end position” (limit evaluation) – for actuators with
electronic control unit and limit switches: check
This test is required for the following versions or configurations:
• Actuator with control unit and limit switches
• One of the following safety functions:
− Safe ESD function “Safe CLOSING” (Safe ESD in direction CLOSE)
− Safe ESD function “Safe OPENING” (Safe ESD in direction OPEN)
• Configuration of “SIL seating”
= “Forced limit seating in end position”
(Safety operation is stopped by limit switch tripping)
During the test, the reaction of the Safe ESD function to limit switch tripping during safety
operation is checked.
1.
Operate actuator in mid-position or at sufficient distance from the end positions.
2. Open the switch compartment
3. Initiate safety operation:
® Set Safe ESDa and Safe ESDb input signals to 0 V (low).
Check seating via limit switches:
Operate limit switches until test is complete:
® For “Safe CLOSING” (Safe ESD in direction CLOSE) configuration: Activate
SIL ESDa / ESDb command until close limit switch trips, then validate the
valve position on EPAC display as 0.00%
® For "Safe OPENING” (Safe ESD in direction OPEN) configuration: Activate
SIL ESDa/ ESDb command until Open limit switch trips, then validate the
valve position on EPAC display as 100%.
The safety function reaction to the limit switch signals is correct if safety operation is
stopped.
4. Set Safe ESDa and Safe ESDb input signals to +24 V DC (high) after the test.
5. Close switch compartment.
NOTICE
16. Resetting limit-switching:
- Operate valve away from end-position to account for over-run or to the desired
switch tripping point.
- Push thrust bolt I inwards and turn (fig. 16). The bolt remains in this position.
- For CLOSED position turn spindle marked (Z), (for OPEN position spindle
marked, (O) slowly as indicated by arrow (fig. 16). Distinct "clicks" can be felt and
heard. Continue turning the spindle until the cam operates the switch. At this stage,
the spindle should not "click" any more and should not be turned any further.
If inadvertently you override the tripping point, continue turning the spindle slowly in
the same direction till the switch cam goes back to its original position. Repeat
setting instructions as above described.
- Turn thrust bolt I till it snaps back into its original position by spring action.
17. Torque switching (fig. 17)
If the actuator is switched off by torque switch over its travel before reaching an
end-position, please check whether the valve stem is damaged or dirt adhering to it.
If necessary, and with the valve maker's consent, the setting of the tripping torque
may be raised slightly.
18. Setting: Figures on the torque switch operating cam indicate the valves in Nm
(1 mkp = 10 Nm. 1 lbsft. = 1.36 Nm).
Loosen screw and turn the cam till the desired torque coincides with the arrow
mark, then fasten lock-screw.
19. Immediately after start-up: Ensure sealing faces at cover and housing are clean.
Check whether O-ring is correctly in position and apply a thin film of non-acid
grease. Replace the cover and fasten with 4 screws (fig. 18)
NOTICE
Fasten control cover screws and tighten glands at conduit entries.
20. Mechanical position indicator: The two dials have a slip clutch for easy adjustment. At
valve fully closed, turn dial (CLOSED) till the arrow is in alignment with the mark on
the show glass. Operate valve into fully OPEN position and adjust dial marked
, (OPEN) till the arrow mark is in alignment with the mark on the cover.
The dial (CLOSED) must be held in position while adjusting dial (OPEN). (fig.19).
Multi-turn actuators
SA series with Control 3.XX /NI/SIL
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