Modbus MFU Option Card Installation Manual
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Publication PUB091-004-00_0918
register (range 0-100.0%, resolution 0.1%). The valve will open to the
appropriate amount and stop in that position (within the deadband
setting). It then drops out of the positioning mode. If a subsequent
digital command to open or close the valve is issued, from any source
during the travel to the set point, this will take priority over the
analogue position command. Once the setpoint is reached the
positioning controller is switched off. A new write to the Position DV
register will initiate positioning mode once more, provided the desired
value is beyond the deadband setting. The register location is listed
later in this manual.
Provided limited range positioning is not invoked, the values 0% and
100% written to this register produce a special case output where the
command is revised so as to fully close the valve to its tight shut off
position (0%) and fully open the valve (100%). This is useful for the
valve types mentioned in the note on the previous page.
Hard Wired Open
The hard wired Open input will cause the actuator to run
to the open limit if there are no alarm conditions or local controls
active and the Auxiliary Input Mask is set to an appropriate value. The
input can be either high or low, depending on the value of the Mask
setting.
Hard Wired Close
The hard wired Close input will cause the actuator to run
to the closed limit if there are no alarm conditions or local controls
active and the Auxiliary Input Mask is set to an appropriate value. The
input can be either high or low, depending on the value of the Mask
setting.
Hard Wired Stop
The hard wired Stop input acts as a change of state
input. If the actuator is moving, opening the Stop input will stop the
actuator. If the Stop input is already open and a Modbus command is
sent to the actuator, the Modbus command will be initiated. To stop
the actuator the hard wired input must be closed and opened again.
Hard Wired ESD
The hard wired ESD input will cause the actuator to move
to its Emergency Shut Down position, which may be to stay put, go
open or go closed. The ESD may also be switched off.
The ESD command can be configured to override Thermostat trip,
Interlocks and Local Stop.
! Danger: Actuator hazardous area
certification is invalidated while the thermostats are bypassed.
Hard Wired Open Interlock
This is one of a pair of interlocks; see below. When
enabled, the actuator will only be able to move if the interlock has the
control input applied. Both open and close interlocks are enabled or
disabled at the same time. If interlocking is required in only one
direction, it will be necessary to fit a link between the terminals
associated with the other interlock. Refer to wiring diagram.
Hard Wired Close Interlock
This is one of a pair of interlocks; see above.
When enabled, the actuator will only be able to move if the interlock
