Flowserve 3400IQ Digital Positioner - Manual (Page 56)

Logix 3400IQ Digital Positioner FCD LGENIM3402-00 – 0/07

Clearing Block Configuration Errors
Block configuration errors prevent the block from leaving OOS mode. The parameter BLOCK_ERR
will show whether a block configuration error is present. Table 10.7 is a list of parameters that can
cause the status of CONFIGURATION ERROR to be set in the AO BLOCK_ERR parameter.
NOTE: CONFIGURATION ERROR can only be cleared if the function block is being executed. One
way of determining block execution is by performing a series two or three reads of the BLOCK_TEST
parameter and confirming that the first byte of the parameter is incrementing. This will work if the
execute rate is fast relative to the speed of reading BLOCK_TEST. A very slowly executing block may
not appear to execute because block parameters are updated only when the block executes.
Parameter Initial Value Valid Range Corrective action
CHANNEL 0 1 Initial value is a configu-
ration error. Set value in
valid range.
SHED_OPT 0 1-8 (see Shed Options in
the FF specs.)
Initial value is a configu-
ration error. Set value in
valid range.
SP_HI_LIM
SP_LO_LIM 100 0 PV_SCALE +/- 10% Verify that SP_HI_LIM >
SP_LO_LIM.
Mode-restricted Write Operations
Table 8.7 lists the AO block parameters which may be write restricted based upon the block’s mode.
Listed in the table are the TARGET and/or ACTUAL modes required for the write to be accepted. Other
limitations listed in the last column must also be met.
SIMULATE, READBACK and PV Determination
In the AO Function Block, these three parameters provide the values and status of the actuator
position, where SIMULATE (or optionally OUT) generates the READBACK parameter and READBACK
is then re-scaled to produce the PV.
The following sub-sections describe each of these parameters.
SIMULATE Parameter SIMULATE is the interface parameter between the AO and the Transducer
Function Blocks. Each time the AO block executes, SIMULATE.TRANSDUCER is updated with the
FINAL_POSITION_VALUE from the transducer block.
When the SIMULATE.ENABLE is FALSE, SIMULATE.TRANSDUCER is copied into SIMULATE.
SIMULATE. When SIMULATE.ENABLE is TRUE, SIMULATE.SIMULATE is not updated with
SIMULATE.TRANSDUCER and the user may write a value and status to SIMULATE.SIMULATE.
NOTE: SIMULATE.ENABLE can only be set TRUE when the Simulate dip switch is in the “On” position
when the device is powered up or a processor restart is issued.
READBACK Parameter The value and status of READBACK will come from either the OUT
parameter or SIMULATE.SIMULATE, determined by the state of the OUT_READBACK feature in the
Resource Block. READBACK is in XD units.
When RS.FEATURE.OUT_READBACK is set TRUE, SIMULATE.SIMULATE is used for READBACK.
When FEATURE.OUT_READBACK is FALSE, OUT will be used for READBACK.
NOTE: The default value for RS.FEATURE.OUT_READBACK is FALSE. With the Logix 3400IQ, this
feature should always be set TRUE to allow the transducer block position value to be the source of
READBACK.
READBACK_OUT ALLOWS THE USER A LINKABLE PARAMETER FOR VALVE POSITION.
PV Parameter The PV value is simply the READBACK value, re-scaled from XD units to PV units.
PV status is copied directly from READBACK status.