Micromod MOD: Modcell 2050R Users Guide - Manual (Page 207)

IB-23C650
DIAGNOSTICS
DIAGNOSTICS
INPUT FAILURE AND POWER FAILURE DETECTION
The fault detection level for volt inputs is determined by the percent of volt
input span value entered in the INPUTS MENU. If there is a process input
signal failure, the controller responds as follows:
• If the recovery option is manual, the controller in the automatic mode is
forced to manual with local set-point and the output value is switched to
the fault output value. The input failure must be corrected and
acknowledged in the DISPLAYS MENU before the controller can be
placed back into auto.
• If the recovery option is last, the controller in the automatic mode is
forced to manual with local set-point and the output value is switched to
the fault output value. The input failure, when corrected, is cleared and
the controller is automatically placed back into auto. If ramp/soak was
running, it will need to be restarted.
• In the manual mode, the controller is not forced to a fault output. The
ramp keys remain functional. The input failure must be corrected and
acknowledged in the DISPLAYS MENU before the controller can be
placed back into auto.
If there is a power failure or shutdown, the relays fail-safe by going to their
alarm state. Upon restart, the displays show [POWER] [FAIL] if the message
was enabled in the BASE CFG MENU. During power-up, the relays remain in
their alarm state until an accurate process input reading is made, after which
the relays follow their configured action.
DIAGNOSTIC MESSAGES
Like process alarms, the controller provides diagnostic messages which alert
the user to input failures or operational problems. Diagnostic messages are
displayed on the TAG line. When one or more unacknowledged process or
diagnostic alarms exist, the red LED on the ALARM key flashes, the alarm
message alternates with the TAG or the value or the alarmed variable (for
process alarms) on the top display, and the beeper sounds if configured to do
so. This activity continues until all alarm and diagnostic conditions are either
acknowledged or no longer active. When only acknowledged alarms exist, the
red LED is steady and the tag display shows only the tag.
Press the alarm key to view messages and acknowledge any unacknowledged
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