rotork Modbus - Page 27

Input and Output Signals
Publication PUB091-004-00_0918 27 of 64
• The Hand/Auto lever is not locked in Hand. If locked in Hand, this will cause a Valve
Jammed or Valve Obstructed alarm.
 Open A digital command to cause the actuator to open to the fully open
position, as indicated by the Open limit switch. Under correct
operation, without either stalling or jamming, the actuator stops either
when the open limit switch is reached, when the torque exceeds the
value set and the open limit switch has been reached, or a new
command is sent over the network. An alarm condition arising during
travel will also cause an unexpected stop of actuator movement.
 Close A digital command to cause the actuator to close to the fully closed
position as indicated by the Close limit switch. Under correct operation
the actuator stops either when the close limit switch is reached, when
the torque exceeds the value set and the close limit switch has been
reached, or a new command is sent over the network. Similarly, an
alarm condition arising during travel will cause an unexpected stop of
actuator movement.
 Stop With no other command present this digital command causes an
actuator motor that is running, to stop.
 Emergency Shut Down (ESD) A digital command that causes the actuator to
drive to its Emergency position. There are settings within the actuator
to configure this to be a close, open or stay-put action. It 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.
 Relay Output DO-1 to DO-4 These 4 commands are used to energise and de-
energise the internal relays on the additional relay board. (These
outputs are referred to as S5-S8 in the standard actuator
documentation when there is no MFU in the actuator.) The resulting
outputs can be used for operating other external equipment such as a
pump or indication light. The IQ3 actuator is not able to control these
relays directly from the main board when the MFU is fitted. They will
maintain their last state if power is removed from the actuator. On
restoration of power the relays will be reset to their de-energised
condition and the coils will report ‘0’.
 Analogue Position Demand The source of this function is only over the Modbus
RS-485 network. (Where multiple network cards or Folomatic is fitted,
then this could be another source of positioning control). To initiate
Analogue Position Control a value must be written to the Position DV
Note: Many multi-turn actuators are set to open until the open limit switch is reached and
close until the torque switch trips. This is appropriate for wedge gate and globe valves.
The actuators can be set to open or close on limit or on torque.