The Alarms Function - Teledyne 2120XL Operating Instructions Manual

Operation
Note: Range 1 must be set lower than range 2 and range two
less than range 3. Only the upper bound of the range may
be changed. The lower value will always remain at 0.
When auto-ranging is selected, the analyzer will automatically
switch to the appropriate range based on the concentration of the sample
gas under test.

4.5.4 The Alarms Function

The Model 2120XL is equipped with 2 fully adjustable concentration
alarms and one non-adjustable system alarm. Each alarm has a relay with
a set of form "C" contacts rated for 3 amperes resistive load at 250 VAC.
Refer to Chapter 3, Installation and/or the Interconnection Diagram
included at the back of this manual for relay connections.
The concentration alarms can be configured from the front panel as
either high or low alarms by the operator. The alarm modes can be set as
latching or non-latching, and either failsafe or non-failsafe, or, they can
be defeated altogether. The setpoints for the alarms are also established
using this function.
Decide how your alarms should be configured. The choice will
depend upon your process. Consider the following four points:
1. Which if any of the alarms are to be high alarms and which if
any are to be low alarms?
Setting an alarm as HIGH triggers the alarm when the
nitrogen concentration rises above the setpoint. Setting an
alarm as LOW triggers the alarm when the nitrogen
concentration falls below the setpoint.
Decide whether you want the alarms to be set as:
 Both high (high and high-high) alarms, or
 One high and one low alarm, or
 Both low (low and low-low) alarms.
2. Are either or both of the alarms to be configured as failsafe?
In failsafe mode, the alarm relay de-energizes in an alarm
condition. For non-failsafe operation, the relay is energized
in an alarm condition. You can set either or both of the
concentration alarms to operate in failsafe or non-failsafe
mode.
Teledyne Analytical Instruments
Model 2120XL
60