Ai Block Troubleshooting - Emerson Rosemount 848T FOUNDATION Reference Manual

Reference Manual
00809-0100-4697, Rev GA
L_TYPE
Select Direct when the measurement is in the desired engineering units for the block
output. Select Indirect when converting the measured variable into another, for example,
pressure into level or flow into energy.
SCALING
XD_SCALE provides the range and units of the measurement and OUT_SCALE provides the
range and engineering units of the output. OUT_SCALE is only used when in indirect or
indirect square root.
D.1.2

AI block troubleshooting

Symptom
Mode will not leave
OOS
Process and/or block
alarms will not work.
Value of output does
not make sense
Cannot set HI_LIMIT,
HI_HI_LIMIT, LO_LIMIT,
or LO_LO_LIMIT Values
Function Blocks
Possible causes Corrective action
Target mode not set Set target mode to something other than OOS.
Configuration error BLOCK_ERR will show the configuration error bit
set. The following are parameters that must be set
before the block is allowed out of OOS:
• CHANNEL must be set to a valid value and cannot be
• XD_SCALE
• L_TYPE must be set to Direct, Indirect, or Indirect
Resource block The actual mode of the Resource block is OOS. See
Resource Block Diagnostics for corrective action.
Schedule Block is not scheduled and therefore cannot execute
to go to Target Mode. Typically, BLOCK_ERR will
show "Power-Up" for all blocks that are not
scheduled. Schedule the block to execute.
Features FEATURES_SEL does not have Alerts enabled. Enable
the Alerts bit.
Notification LIM_NOTIFY is not high enough. Set equal to
MAX_NOTIFY. Alarm not linked to host.
Status Options STATUS_OPTS has Propagate Fault Forward bit set.
This should be cleared to cause an alarm to occur.
Linearization Type L_TYPE must be set to Direct, Indirect, or Indirect
Square Root and cannot be left at initial value of 0.
Scaling Scaling parameters are set incorrectly:
• XD_SCALE.EU0 and EU100 should match that of the
• OUT_SCALE
• Both STB on each ASIC used must by in auto.
Scaling Limit values are outside the OUT_SCALE
OUT_SCALE
set values within range.
Appendix D: Function Blocks
left at initial value of 0.
.
UNITS_INDEX must match the units in the
transducer block channel value. Setting the units in
the AI block automatically sets them in the
XD_BLOCK.
Square Root and cannot be left at initial value of 0.
transducer block channel value.
.
EU0 and EU100 are not set properly.
.
EU100 values. Change OUT_SCALE or
November 2014
.
EU0 and
105