The Alarms Function - Teledyne 4020 Operating & Maintenance Manual

Operation
The calibration process will initiate and after a few moments the
LED digital display will indicate the zero or span gas concentration and
the VFD display will inform the user it has finished the calibration.
<Enter> To accept the calibration, press <Enter>. To reject this
calibration and repeat the process, press <Escape>.
The zero (span) process will automatically conclude when the output
is within the acceptable range for a good zero (span). If accepted by the
operator, the analyzer automatically returns to the Analyze mode.

4.6.12 The Alarms Function

The Model 4020 is equipped with one fully adjustable concentration
alarm and a non-adjustable system failure alarm. Each alarm relay has a
set of form "C" contacts rated for 3 amperes resistive load at 250 VAC.
See Figure in Chapter 3, Installation and/or the Interconnection Diagram
included at the back of this manual for relay terminal connections. The
alarm relay contacts are accessible to the user from the 50-pin
Equipment Interface connector.
The system failure alarm has a fixed configuration described in
Chapter 3 Installation.
The concentration alarm can be configured from the ALARM
function screen as either a high or low alarm by the operator. The alarm
mode is set at the factory as non-failsafe however it can be defeated by
the operator from within the ALARM function screen. In failsafe mode,
the alarm relay de-energizes in an alarm condition. For non-failsafe
operation, the relay is energized in an alarm condition.
The setpoint for the alarm are also established using this function.
Prior to programming the alarm you should decide how it should be
configured. The choice will depend upon your process. Consider the
following points:
 Should the alarm be a high alarm or low alarm?
Setting an alarm as HIGH triggers the alarm when the
concentration rises above the setpoint. Setting an alarm as
Teledyne Analytical Instruments
Model 4020
50