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Reference Manual
00809-0100-4696, Rev AA
September 2004
C-11
Rosemount 848L
DISCRETE OUTPUT
BLOCK
The DO block makes the value sent in SP_D, CAS_IN_D, or RCAS_IN_D
available for processing by the device. The CHANNEL selection determines
where the value is stored in the 848L. A custom feature of the DO block in the
848L is the ability to accept 8 status bits packed into the single setpoint of a
DO block. This is accomplished by selecting the appropriate channel number
for packed data. This feature is used in custom applications implemented in
control systems such as DeltaV.
The Invert I/O option can be used to do a Boolean NOT function on the
setpoint value.
The SP_D supports the full cascade sub-function. Cas mode must be used to
transfer the output of another block to the SP_D of the DO.
There are additional I/O options which will cause the SP_D value to track the
PV_D value when the block is in an actual mode of LO or Man.
The 848L does not support a readback value in which case READBACK_D is
generated from OUT_D. The OUT_D and READBACK_D parameters both
use XD_STATE. The PV_D and SP_D use PV_STATE.
Supported Modes O/S, LO, Iman, Man, Auto, Cas, and RCas. The Man mode can be used to
force the output, in a PLC sense. It may be that Man mode is not permitted,
but it must be supported so that Man mode may be entered when leaving
O/S. The IMan mode is used to indicated that there is no path to the final
element. IMAN is not used in the 848L.
Setpoint
Optional
Invert
Output
Simulate
SIMULATE_D
CHANNEL
OUT_D
READBACK_D
PV_D
Fault State
FSTATE_TIME
FSTATE_VAL_D
SP_D
Optional
Invert
MODE
SHED_OPT
BKCAL_OUT_D
RCAS_OUT_D
CAS_IN_D
RCAS_IN_D
848/848L/DISCRETE2.EPS