www.miinet.com
Moore Industries-International, Inc.
- 61 -
User’s Manual
225-748-01L
February 2017
Input diagnostics
The STA has extensive hardware diagnostics of the input to detect broken wire and saturation. It
also detects out of range and linearization errors.
Broken wire
is automatically set on the STA and enables the system to distinguish between a
low trip condition (which sets the trip alarm) and a failed transmitter or open input (which sets the
fault alarm).
All input faults will be alarmed on the fault relay. Depending on the configuration, they may
or may not be latched (default is latched). A latched input fault alarm can be cleared by first
clearing the input failure and then using the configuration menus or MR (if configured) to reset
faults. If the input error is not cleared when resetting the fault alarm, the error condition will
immediately be re-applied and will not cause the relay to glitch.
Note:
For STA units with firmware versions 1.5 and earlier, the fault alarm has no configuration
options, is always latched and cannot be reset by MR.
Note:
The trip alarms are independent from the fault alarm and will be unaffected by the fault
alarm. Therefore if the trip alarm has already been activated it will remain so but will NOT be
activated by a broken wire or input saturation error. The analog output (AO) will respond to an
input error and will be set to its programmed fail response. For broken wire detection, this only
applies if the input is immediately broken. If there is degradation of sensor wires, false readings
could occur before the wire breaks and the trip alarm could be activated before the fault alarm.
(Slow degradation is characterized by events that occur over a span of a second or so).
STA Diagnostic Messages
Every STA is subjected to a complete suite of operational checks and tests prior to its shipment.
Occasionally, however, units can sustain damage in transit from the factory to the user.
The STA is also equipped with a full set of internal diagnostics that check operation and
configuration upon power-up. If there are problems with the unit, or with conflicting operating
parameter settings, the LCD will display an error message upon unit start-up, and the fault alarm
will remain set. Identical diagnostics are performed in the background during run time. If a fault
is detected, the fault alarm will immediately be set, and an error message will be displayed.
Table 6.1 provides a full list of diagnostic messages and corrective actions.
Programmable Current/Voltage Safety Trip Alarm
STA
HLPRG
SEC
TION 6
