Teledyne 3000TA-XLEU - Trace oxygen analyzer - Manual (Page 71)

Trace Oxygen Analyzer Operation
Teledyne Analytical Instruments 55
4.5.1 Special Notes on Hydrogen Gas Stream
The standard oxygen cells, Model B-2CXL and Insta-Trace, though
tested in nitrogen gas streams, are expected to perform well in hydrogen
streams. However, for certain applications such as continuous
monitoring of very low levels of oxygen in hydrogen, the user may
request cells that have been specifically tested in hydrogen streams.
Consult Teledyne for further details.
4.6 The Alarms Function
The Model 3000TA-XL-EU is equipped with 2 fully adjustable
concentration alarms and a system failure alarm. Each alarm has a relay
with a set of form “C" contacts rated for 3 amperes resistive load at 250
VAC. See Figure 3-5 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 as 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 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 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
oxygen concentration rises above the setpoint.
 Setting an alarm as LOW triggers the alarm when the
oxygen concentration falls below the setpoint.
2. 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.