Troubleshooting The Analog Input (Ai) Block; Table 24: Analog Input Block - Honeywell ST700 User Manual

Troubleshooting the Analog Input (AI) block

Problem cause
Analog Input block mode
is in OOS and does not
change to AUTO mode.
Analog Input block mode
is in OOS mode with
Block Configuration Error.
Value of output seems
wrong.
Process and block alarms
do not work.
Cannot set alarm limits.
Page 102 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide

Table 24: Analog Input block

Things to check
Read
MODE_BLOCK.PERMITTED
Read MODE_BLOCK.
ACTUAL of Resource block.
Read WRITE_LOCK
parameter in resource block.
Check if device is in Write
Protect mode.
If WRITE_LOCK = Locked (2)
Schedule
Read CHANNEL parameter
and range.
Read L_TYPE parameter.
Check if L_TYPE= Direct
Read Linearization Type.
Read Scaling.
Read FEATURE_SEL.
Read LIM_NOTIFY
Read Alarm Summary Disable.
Read Scaling.
Recommended action
Add AUTO mode to
MODE_BLOCK.PERMITTED.
If necessary, Set
MODE_BLOCK.TARGET to AUTO.
NOTE: If the mode is set to OOS for
maintenance, then do not change the
mode to AUTO.
Change Write Protect jumper to "W"
position. (See section 6.6)
Reset the device. (Cycle power to
transmitter or write "Processor" to
RESTART parameter in Resource block.)
Block is not scheduled and therefore
cannot execute to go to Target Mode.
Schedule the block to execute.
CHANNEL must be set to a valid value
and cannot be left at the initial value of
zero.
XD_SCALE.UNITS_INDX must be
compatible with the units in the transducer
block for the channel.
L_TYPE must be set to Direct, Indirect, or
Indirect Square Root and cannot be left at
the initial value of zero.
When L_TYPE = Direct, XD_SCALE and
OUT_SCALE must contain the same
range values (EU_0 and EU_100).
Check the L_TYPE setting.
Check XD_SCALE and OUT_SCALE
Reports are not selected in
FEATURE_SEL. If features do not include
Reports then the host must poll for alarms.
Set LIM_NOTIFY to a value higher than
zero, but not higher than MAX_NOTIFY.
Check that process and block alarms are
not disabled.
Limit values are outside the
OUT_SCALE.EU_0 and
OUT_SCALE.EU_100 values. Set values
within range.
Revision 2.0