Discrete Output (Do) Function Block Overview; Modes - Emerson FIELDVUE DVC6200f Instruction Manual

DVC6200f Digital Valve Controller
CAS_IN_D
CAS IN D = The remote set point value from
another function block.
BKCAL OUT D = The value and status required by the
BKCAL IN D input of another block for
output tracking.
OUT_D = The block output and status.
READBACK_D = Actual valve position
4
Figure 4-26. Discrete Output (DO) Function Block
Discrete Output (DO) Function Block
Overview
The Discrete Output (DO) function block processes a
discrete set point and outputs it to the specified I/O
channel to produce an output signal. The DVC6200f
digital valve controller discrete output block provides
both normal open/closed control and the ability to
position the valve in 5% increments for coarse
throttling applications. The digital valve controller
measures and uses actual valve position for
READBACK_D [16].
The DO block supports mode control and simulation.
In operation, the DO function block determines its set
point and sets the output. The transducer block
provides a readback signal of actual position from the
instrument. Figure 4-26 illustrates the primary inputs
and outputs of the DO function block, figure 4-27
illustrates the internal components of the DO function
block. Table 4-72 lists definitions for the function block
parameters.
When setting up the DO block, CHANNEL [18] must
be set to 22, and SHED_OPT [23] must be non-zero.
Note
Actual Block Mode
(MODE_BLK.ACTUAL [5.2]) will remain
out of service and the block cannot be
scheduled if the block has not been
licensed. Contact your Emerson
Process Management sales office to
upgrade product licensing.
178
BKCAL_OUT_D
DO
OUT_D
READBACK_D
Note
Actual Block Mode
(MODE_BLK.ACTUAL [5.2]) will remain
in IMAN and the block Readback
status will be Bad − Not Connected if
the Output Block Selection is set
incorrectly. From the transducer block
method Outblock Selection, select the
desired output block, see page 427.

Modes

The DO block supports the following modes:
D Manual (Man)—The block output OUT_D [9]
value may be entered manually.
D Automatic (Auto)—The block algorithm uses
the local set point SP_D [8]value to determine OUT_D
[9].
D Cascade (Cas)—The block uses a set point
supplied by another function block.
Note
The transducer block must be in Auto
for the mode to go to AUTO, CAS or
MAN.
D RemoteCascade (RCas)—The block uses a set
point supplied by a host computer.
D Out of Service (OOS)—The block is not
processed and the output is not transferred to I/O. The
BLOCK_ERR [6] attribute shows Out of service.
November 2010