rotork Mk3 - Page 37

Actuator Input Output Signals
Publication PUB089-005-00_0618 37 of 116
 General Alarm If any of the following conditions are true this bit will be true (1):–
Thermostat tripped
Monitor Relay
Valve Obstructed
Valve Jammed
Manual Movement
 Valve Obstructed This bit will be true (1) if the actuator stops in mid-travel when not
expected to do so after receiving a command to move. If the actuator
torque exceeds the trip value set during commissioning, then the
motor will stop and motion will cease. The reason for the actuator
stopping will be the high torque due to an obstruction and not a ‘Stop’
signal or reaching the desired setpoint position.
The bit will remain true (1) until the actuator position changes by 2%
or more.
 Valve Jammed This bit will be true (1) if the actuator is stationary at the end of travel
and fails to move away from the seat of the valve when a network
command requests it to do so. The actuator will trip on excessive
torque due to the valve being jammed in the seat. The FF CP card
fails to see movement and reports this status after the time set in the
associated Transducer block parameter during set-up.
The bit will remain true (1) until the actuator position changes by 2%
or more.
 Moving Inhibited This bit will be true (1) when the Motion Inhibit Timer is active or the
Interrupter Timer is active, or both are active.
The Motion Inhibit Timer is used in position control to prevent the
actuator from exceeding its prescribed number of starts per hour, or to
reduce the effects of hunting during closed-loop control.
The Interrupter Timer can be used over part or the entire actuator
stroke to slow down the effective speed of valve travel.
When under network control, the control signal does not need to be
re-applied when this bit is true, as the control action will continue once
the time has elapsed.
Note: Attempting to restart the actuator to move towards the obstruction (even if the
obstruction no longer exists) is not possible, the actuator will not restart. The actuator
must be electrically reversed away from the obstruction before attempting to continue in
the original direction.
Note: Attempting to restart the actuator to move out of the seated position is not possible. The
actuator must be reversed before it will run in the same direction again. The jammed
seat must first be released manually before electrical control is attempted. The problem
may be overcome by adjusting the actuator torque setting, which is designed to provide
extra power on leaving the seated position.