Ametek Thermox 2000 ATEX Series, User Manual

Page: 99 / 202

Controller / User Interface | 4-31
Alarm3= Cal/Verif y, depending on whether alarm 3 should be
associated with % oxygen levels, or with the start of a calibration or
verification, or with the start of a calibration or verification (dual
function).
The control unit automatically exits you from this menu after you make
your selection.
Service Alarm
The service alarm operates as normally closed (service alarm
condition causes open contacts).
The service alarm provides an alarm that alerts you of possible system
problems that require attention. Events that can trigger the service alarm
to activate are as follows:
y
Error condition (detected by software)
y
System operational variance (such as an over-temperature or under-
temperature condition)
y
Calibration failure
y
Verification failure
y
Control unit power failure
Watchdog Relay
During normal system operation, the watchdog relay operates as
normally closed (system failure causes open contacts).
The watchdog alarm relay de-energizes when the system watchdog timer
times out. The watchdog timer will time out and cause the control unit
to reset itself to prevent the control unit from becoming “lost” due to
such things as noise spikes or power surges. You can use this relay to
activate a remote indicator to notify you if the watchdog timer times out.
NOTE
NOTE