Teledyne 7300A manual 4.5The Alarms Function, Installation, Infrared Gas Analyzer, Operation

Infrared Gas Analyzer Operation 4

is pressed, the Spanreading changes to the correct value. The instrument then automatically enters the Analyze function.

4.5The Alarms Function

The Model 7300A is equipped with 6 fully adjustable set points concentra- tion with two alarms and a system failure alarm relay. Each alarm relay has a set of form “C" contacts rated for 3 amperes resistive load at 250 V ac. See Figure in Chapter 3, Installation and/or the Interconnection Diagram included at the back of this manual for relay terminal connections.

The system failure alarm has a fixed configuration described in chapter 3

Installation.

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 fail-safeor non-fail-safe, 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 contaminant concentration rises above the setpoint. Setting an alarm as LOW triggers the alarm when the contaminant 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.

3.Are either of the alarms to be latching?

In latching mode, once the alarm or alarms trigger, they will remain in the alarm mode even if process conditions revert back to non-alarm conditions. This mode requires an alarm to be recognized before it can be reset. In the non-latching mode, the

Teledyne Analytical Instruments 4-21