Profibus DP Mk2 Option Card Installation Manual
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Publication PUB088-005-00_1017
but whilst the Profibus outputs are being written the positioner is
continuously being updated. A new value in the Position DV register
will cause a new position to be adopted and a new bit set in the
ACTCON register will cancel positioning mode.
Provided limited range positioning is not invoked the values 0% and
100% written to the Position DV 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%).
Partial Stroke
The actuator will move the valve to an intermediate position and back
to the start position provided it is at the correct end of travel position
when the command is issued. The end to start from and the amount of
travel are selected during parameterisation.
Multiport Position
On
multiport actuators the port to move to can be selected using this
command. The actuator will move directly to the selected port. Valves
with up to 10 ports can be controlled.
Relay Output DO-1 to DO-4
These 4 commands are used to energise and de-energise the internal
relays on the extra relay indication board in an IQ or IQT actuator.
(These outputs are referred to as S5-S8 in the standard actuator
documentation when there is no Profibus DP Module in the actuator.)
The resulting outputs can be used for operating other equipment such
as a pump or indication light. The IQ/IQT actuator is not able to control
these relays directly from the main board when the PFU 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’.
Hard-Wired Open and Close
These commands operate the actuator in the same way as the open
and close commands sent over the Profibus highway.
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 Profibus command is sent to the
actuator, the Profibus command will be initiated. To stop the actuator
the hard-wired input must be closed and opened again.
Hard-Wired ESD (Network Disable
) The hard-wired ESD may be set to causes the
actuator to drive to its Emergency position. Alternatively, the input can
be used to disable Profibus network control. The function of the input
is determined by the parameterisation set into the PFU.
