Fisher FIELDVUE DVC6200f Instruction Manual page 194

Detailed Setup—DO Function Block
July 2013
Auto—On failure of a remote cascade connection, the block sets the target mode to Auto, if permitted.
Man—On failure of remote cascade connection, the block sets the target mode to Man, if permitted.
The user may configure SHED_OPT [23] so that it calls for a target mode that is not permitted. When doing this, the
mode logic uses the following rules as applied by the remote logic:
D Shed logic never results in a non‐permitted target mode.
D Shed logic never attempts to attain an actual mode of Auto or Cas if that mode is not permitted.
Block Initialization
The Fieldbus Foundation specification requires that certain parameters have initial values of uninitialized in function
blocks. In addition to setting the Resource block mode to AUTO, the control system or the user must change those
parameters from their uninitialized value to a valid value in order for the function block to move from the Out of
Service mode. For the DO function block, the parameters that must be initialized are:
SHED_OPT [23] (see page 191 for valid values)
CHANNEL [18]
Status Handling
Under normal operating conditions, the status of OUT_D [9] is Good Non‐Cascade, and the status of BKCAL_OUT_D
[21] is Good:Cascade. If the output hardware fails, the status of BKCAL_OUT_D [21] is set to Bad:Device Fail, and the
BLOCK_ERR [6] shows Output Failure. If the hardware used for output feedback fails, the status of READBACK_D [16]
and PV_D [7] is set to Bad:DeviceFail, and the BLOCK_ERR [6] shows Process Variable has Bad Status. If the transducer
block mode is Out of Service, the status of READBACK_D [16] and PV_D [7] is set to Bad:Out of Service.
I/O Selection
To select the I/O associated with the discrete output, configure the value of the CHANNEL [18] parameter. Table 4‐69
lists the valid Channel selections for the DO block.
Table 4‐69. Channel Selections for the Discrete Output Function Block
Selection
22
0
Setting the Output
To set the output for the DO block, you must first set the mode to define the manner in which the block determines its
set point and output. In Cascade mode, the set point equals the input value at the CAS_IN_D [17] parameter. In
Automatic or Manual mode, the set point must be entered manually by the user. For Automatic, the value must be
written to the SP_D [8] parameter and for Manual, the value must be written to OUT_D [9]. In Remote Cascade mode,
the set point is determined by a host computer that is writing to the RCAS_IN_D [22] parameter. Table 4‐70 lists
discrete states used by the digital valve controller for the set point.
192
Transducer Block Parameter
SETPOINT_D
-
Transducer block Index
32
-
Instruction Manual
D103412X012
Description
Discrete Valve Control
Uninitialized