Flowserve MX/QX Profibus DP/PA Field Unit - Manual (Page 45)

45
PB DPV1 / PA Field Unit Installation and Maintenance FCD LMENIM2336-03 – 12/12
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Figure 3.6 – Analog Output Function Block
Discrete Input Function Block
Value Status
Value Status
Value Status
Value Status
Value Status
Value Status
On
Value Status
MODE- and STATUS-
Handling
OUT
RCas Auto
Simulate
Parameter
Acyclic Configuration Parameters
Command to
Actuator Hardware
Status
Enable
Simulate
Valve and
Status
READBACK
POS_D
CHECKBACK
Value Status
OUT
OUT
OUT
Off
Man
LO
O/S
Value Status
FB
Algorithm
Value Status
RCAS_OUT
RCAS_IN
FB
Algorithm
SP/ RCas
Auto
SP
RCAS_IN
Status
Configuration Parameter
Configuration Parameter
From Transducer
(In_Channel)
To
Network
User
To
Network
User
Configuration Parameter
Cyclic
Process
Data
Cyclic
Process
Data
From
Network
User
Inputs
SP (cyclic) is the desired output value from an operator.
RCAS_IN (cyclic) is the desired output value from a remote station that is used when actual block
mode is RCas.
IN_CHANNEL (acyclic) represents the transducer block channel number from which readback data
originates and designates the actual position of the final control element. The data from this channel
is read through the block READBACK algorithm.
OUT_CHANNEL (acyclic) represents the channel number to which the AO block will send its output
“command” data.
INCREASE_CLOSE (acyclic) determines the direction of the positioner in mode RCAS and Auto.
INCREASE_CLOSE
0 Rising (increasing of setpoint-input results in OPENING of the valve)
1 Falling (increasing of the setpoint-input results in CLOSING of the valve)
Outputs
The output of the function block can be set in three ways. When the block is in Manual Mode, the
output can be set by the user with a configuration tool. The setpoint parameter is ignored during
Manual Mode. In Automatic Mode, the output is set by the Setpoint value in engineering units. In
Remote Cascade Mode, the setpoint comes from a remote computer/station. This variable is sent to
the Transducer Block where some action will be taken.
RCAS_OUT (cyclic) is the function block setpoint in units of PV_SCALE and status, and is provided
to a supervisory host for monitoring/back calculation and to allow action to be taken under limited
conditions or mode change.
READBACK (cyclic) is the actual position of the final control element within the travel span (between
OPEN and CLOSE position) in units of PV_SCALE.