Watlow Series 920 Microprocessor-Based Ramping Control - Manual (Page 54)

Chapter 7
How To Use the Series 920 Alarms
One of the most versatile features of the Watlow Series 920 is its capability for
alarms. The alarms can be automatic signals for process error or temperature
related event-type actions in your system.
To use the alarms to their fullest extent, you need to understand what they are
and what they will do. Here’s an overview of the different alarm parameters
again. Although you may already be aware of the alarms, notice how these
parameters interact.
Alarm Relay Configuration
Series 920 alarm relays are configured to de-energize when the ACTUAL value
is beyond the alarm limits. Normally open contacts are thus closed when
temperatures are “OK.” That way alarm conditions exist if power is lost from
the control.
Number Of Alarms
There are two alarms in the Series 920, ALARM 1 and ALARM 2. They
indicate an alarm condition, or a de-energized alarm relay with a flashing
“ALMX
- XX” in the alphanumeric display. By retaining the indication of a
previous alarm condition, an operator absent from the control panel can be
aware that an alarm occurred. We’ll look more closely at that later in this
chapter.
54 WATLOW Series 920 User’s Manual How To Use The Alarms, Chapter 7