Modbus MFU Option Card Installation Manual
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Publication PUB091-003-00_0119
Note that when limited range positioning is used and the actuator is in the fully closed position a DV
value of 0%, or when the actuator is in the fully open position a DV value of 100%, are not acted upon.
5.1.5
The IQ ‘S’ contacts (Modbus DOs).
The IQ/IQT actuator has four ‘S’ contact outputs that may be configured to report the status of the
actuator with signals such as Open Limit, Closed Limit etc. These are identified as S1 to S4.
In addition, an optional additional relay board can be fitted with four more relays. The status of these
relays is then adjusted by Modbus commands on outputs DO-1 to DO-4. Note that these relays are
latching and, if energised, will not change state when the actuator power is removed. On restoration of
power the relays will be reset to their de-energised condition and the coils will report ‘0’.
5.1.6
IQ Modbus Network Control Disable feature
It is possible to set the IQ or IQT ESD/DI-4 input so that the IQ/IQT actuator ignores open, stop, close,
ESD and position control signals sent over the Modbus network. If the ESD DI-4 / Net Disable
parameter is set to Active then when the ESD input is connection is made (i.e. 24 volts applied to
ESD), Modbus control is not allowed. This feature is independent of the Auxiliary mask setting. When
the ESD DI-4 / Net Disable parameter is set to active, no ESD will be available.
5.2 Actuator Digital Input Status Feedback
The Modbus Module can report over the network a comprehensive data set relating to the status of
the valve and actuator as indicated in the table below. The conventional contact indications are also
available from the actuator limit switches and indication contacts.
Status Feedback
IQ / IQT actuator
SI / EH actuator
ROMpak / Q actuator
Actuator Moving
Close Limit
Open Limit
Running Closed
Running Open
Remote selected
Local Stop selected
Local selected
Fig 24: IQ and IQT relay outputs DO-1 to DO-4
S1 - S4
Actuator
Main
Board
IQ or IQT with Additional Relay Output board fitted
DO-1to DO-4
Output Board
MFU