Flowserve MX/QX Profibus DP/PA Field Unit - Manual (Page 44)

PB DPV1 / PA Field Unit Installation and Maintenance FCD LMENIM2336-03 – 12/12
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• LO_LIM, LO_LO_LIM, HI_LIM, and HI_HI_LIM – If the measured variable is equal or surpasses
these limits, the limit bits in the Status byte of OUT and the FB parameter ALARM_SUM change to
1. The unit of this parameter is the same as the OUT parameter.
• ALARM_SUM – This parameter summarizes the status of the Function Block alarms.
Simulate (Acyclic)
For commissioning and test purposes, the input value from the transducer block going to the Analog
Input function block can be simulated. That means the Transducer and AI-FB will be disconnected
when simulation is enabled. The network user can provide the AI block with “fake” process data to
test other portions of the system.
This feature requires the installation of a hardware jumper on the MX/QX PB unit, located on header
X5, Pins 3-4.
3.4 Analog Output (AO) Function Block
The Analog Output (AO) block accepts a “command” value from the network user. This command
value flows through the AO block algorithm. The AO block then provides this “command” data to the
transducer block and the actuator takes some action based on this “command.” The function block
also provides readback data, allowing the network user to configure closed loop control processes.
The AO block supports mode control, signal limiting, rate limiting, signal status calculation, and
simulation.
There is one AO block in the MX/QX actuator device. There is only one transducer block channel
available for this Function Block to send “command” data to.
Channel Channel Name Description
344 AO_CNTRL_VALVE_FLOW_CHAN Desired valve position percent
NOTE: Please note that the quality status bit must be set to “good”, prior to or while sending
command data. This is required in order for the actuator to respond to AO block commands. See
“Status Bit Definitions” section on page 70 for coding of quality status bits.
Figure 3.5 – Summary of the Parameters of the Analog Output Block
AO
Function
Block
SP
READBACK
POS_D
Standard Configuration Parameters
(Acyclic Data)
Example: OUT_SCALE
PV_SCALE
Process Parameter
(Cyclic Data)
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