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Reference Manual
00809-0100-4697, Rev EA
October 2011
Rosemount 848T
D-14
Application Information
The intended use for this type of function block is for applications where the
sensor types and functionality of each channel (i.e. the simulate, scaling,
filtering, alarms type, and options) are the same.
The configuration of the MAI function block and its associated output
channels depends on the specific application. A typical configuration for the
MAI block involves the following parameters:
CHANNEL
If the device supports more than one measurement, verify that the
selected channel contains the appropriate measurement or derived value.
Refer to Table D-4 on page D-6 for a listing of available channels on the
848T.
L_TYPE
Select Direct when the measurement is already 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.
Select Indirect Square Root when the block I/O parameter value
represents a flow measurement made using differential pressure, and
when square root extraction is not performed by the transducer.
SCALING
XD_SCALE provides the range and units of the measurement and
OUT_SCALE provides the range and engineering units of the output.
MAI Block
Troubleshooting
Symptom Possible Causes Corrective Action
Mode will not leave OOS 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:
• Initial value is 1.
• XD_SCALE
.UNITS_INDEX must match the units in all the corresponding
sensor transducer blocks.
• L_TYPE must be set to Direct, Indirect, or Indirect Square Root and cannot be
left at initial value of 0.
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.
Process and/or block
alarms will not work.
Features FEATURES_SEL does not have Alerts enabled. Enable the Alerts bit.
Notification LIM_NOTIFY is not high enough. Set equal to MAX_NOTIFY.
Status Options STATUS_OPTS has Propagate Fault Forward bit set. This should be cleared to
cause an alarm to occur.
Value of output does not
make sense
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 corresponding sensor
transducer block.
• OUT_SCALE
.EU0 and EU100 are not set properly.
• Both STBs in an ASIC must be set to auto. Best in 1, 2, 7, 8, ASICs in Auto for
thermocouples