Endress+Hauser Proline Promag 55 Operating Manual page 119

Device functions Proline Promag 55 FOUNDATION Fieldbus
Endress+Hauser
6 Discrete Output Function block
The Discrete Output function block (DO, Discrete Output) processes a discrete setpoint value
received from an upstream function block or higher level process control system, with which
various instrument functions (e.g. zero point adjustment or totalizer reset) can be initiated in the
downstream Transducer Block.
CAS_IN _D = Remote setpoint value from another function block
OUT_D = Discrete output value and status
BKCAL_OUT_D = Discrete output value and status required by BKCAL_IN_D input of another block for
6.1 Signal processing
The figure shows the internal structure of the Discrete Output function blocks Promag 55
FOUNDATION Fieldbus:
Discrete Output Function Block
RCAS_IN_D
(Mode RCAS)
CAS_IN_D
(Mode Auto)
Fig. 5: Signal processing in the Discrete Output function block
In the CAS operating mode (cascade operation), the Discrete Output function block receives, via the
function block input CAS_IN_D, a discrete signal from an upstream function block. This signal
controls the setpoint value (parameter SP_D) of the function block, and after internal calculation is
sent as an output signal (parameter OUT_D) to the Transducer Block for control of instrument
functions (e.g. zero point adjustment). The output value and status of the Discrete Output function
block is communicated to the upstream block via the output BKCAL_OUT_D.
Signal processing in the RCAS operating mode (remote cascade operation) is largely identical to the
CAS operating mode. However, in this operating mode, control of the parameter SP_D does not take
place via an upstream function block but through a process control system. The output value and
status of the Discrete Output function block is communicated to the process control system as an
answer message via parameter RCAS_OUT_D.
DO
CAS_IN_D OUT_D
BKCAL_OUT_D
RCAS_OUT_D
SP_D
Invert.
(Mode CAS)
MODE_BLK IO_OPTS
SIMULATE_D
Discrete
Input
Transducer Blocks
6 Discrete Output Function block
BKCAL_OUT_D
PV_D
OUT_D
(Mode Man)
SIMULATE_D
Discrete
Output
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