O2 20.9, 0 operation – ENMET ISA-60M with MRI-5175 User Manual

Page 13

ISA-60M

ENMET Corporation

4.0 Operation

4.1 Normal Operation Condition

With the

ISA-60M

installed as described in Section 3, and in clean air, the

POWER

green LED is on, the display is lit, and the

information on the display is as shown in Figure 6, for the sensor(s) installed in the

ISA-60M.

The red alarm and fault LEDs

are not lit.

Example of display

Figure 6: ISA-60M

Operational Display

4.2 Alarm Set Points

There are two alarm set points for each active oxygen channel. They are adjustable from 16.0 to 24.9. The standard factory
settings of these alarm set points are:

Alarm 1

is 19.5 % by volume, indicated by Flashing LED and audio alarm.

Alarm 2

is 17 % by volume, indicated by Steady LED and alarm 1 LED changes from flashing to steady.

These alarm set points can be changed within limits; see the maintenance section of this manual for the procedure.

If the oxygen content of the sample air decreases below an alarm set point, the associated red LED activates, the associated
relay changes state, and the audio alarm is activated.

Differential Setting (Non Factory)

Differential is an optional alarm relay configuration where when an alarm has been triggered, the relay will remain in alarm
state until the sensor reading has moved the differential “value” in the non-alarm direction. See example below.

The Alarm 1 differential value is the delay of the

ISA-60M

staying in alarm condition until after the measured reading has

returned past the alarm point by the differential value. Example: If the alarm point is

19.5 and the differential is 2, the

ISA-60M

will go into alarm at 19.5 and stay in alarm until the reading has risen above 19.7.

AUTION

Setting the alarm points to the differential setting disables the audio alarm for alarm point 1. The differential Setting

has no effect on alarm relays or on the audio alarm for alarm point 2.

4.3 Fault Indications

Fault indications are associated with sensor zero and calibration activities, and are described in the maintenance section 5.0 of
this manual.

4.4 Alarm Latching

An instrument is shipped with the alarms in the latching mode. The alarms may be independently configured in the non-
latching mode or differential setting by use of the maintenance menu. See Section 5.2.2, for setting alarm 1 and alarm 2.

Standard Setting

N THE LATCHING MODE

: at the cessation of the condition which causes an alarm, the alarm indications do not cease, and the

alarm relay contacts do not revert to the non-alarm state, until the

ALARM ACKN/AUDIO DEFEAT

switch is pressed. An

alarm can also be acknowledged by pressing the switch during the alarm condition; then at the cessation of the alarm
condition, alarm indications cease and alarm relays revert to the non-alarm state. After an alarm is acknowledged, alarms in
the latching configuration are re-armed to latch at the next alarm condition.

N THE NON

LATCHING MODE

at the cessation of the condition that causes an alarm, the alarm indications automatically

cease, and the alarm relay contacts revert to the non-alarm state.

4.5 Audio Defeat

Pressing the

AUDIO DEFEAT

ALARM ACKNOWLEDGE

switch during an alarm temporarily silences the audio alarm on the

ISA-

60M

not on the

MRI-5175

. Relays and alarm LEDs continue to function, in the alarm state, during an alarm condition. As

long as the alarm condition persists, the audio alarm will “chirp” every 20 seconds. After the alarm condition clears, the audio
will continue to “chirp” until the audio switch is pressed.

If after 15 minutes the alarm condition continues the audio alarm will reactivate at full intensity.

If any other alarm condition occurs while the audio alarm has been silenced it will force the audio alarm to reactivate
immediately.

O2 20.9