Emerson manual DISCRETE OUTPUT BLOCK Supported Modes, Rosemount 848L, Reference Manual

Reference Manual

00809-0100-4696, Rev AA September 2004

Rosemount 848L

DISCRETE OUTPUT BLOCK

Supported Modes

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.

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.

CAS_IN_D

RCAS_IN_D

Setpoint

MODE SHED_OPT

BKCAL_OUT_D

RCAS_OUT_D

Optional

Invert

SP_D

Optional

Invert

Output

PV_D

Fault State

FSTATE_TIME FSTATE_VAL_D

Simulate

SIMULATE_D

READBACK_D

OUT_D

CHANNEL

848/848L/DISCRETE2.EPS

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