00 ppm, Advanced instruments inc, Alarms – Analytical Industries GPR-1600 Series Trace PPB Oxygen Analyzer User Manual
Page 28
Advanced Instruments Inc.
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If the oxygen reading exceeds 99.9% of the full scale fixed range manually selected, the system displays the following:
* MAIN MENU
Sample
Span
Zero
Alarm
System
Standby
Sample
5.00 PPM
OVER RANGE
Manual Range
85⁰F 100Kpa
0 to 10 PPM
12/31/07 12:00:00
Alarms
The analyzer is configured with two user adjustable threshold type alarm relays that can be configured in the field from the
ALARM option on the MAIN MENU as follows:
¾ Establish independent set points
¾ Either Hi or Lo
¾ Either On or Off (enabled or disabled)
¾ Both temporarily defeated using a user entered ‘timeout’ period (normally minutes)
The alarm set point represents a value. When the oxygen reading exceeds (high alarm) or falls below (low alarm) the alarm set
point, the relay is activated and the LCD displays the alarm condition.
When activated the alarms trigger SPDT Form C non-latching relays @ 5A, 30VDC or 240VAC resistive. To prevent chattering of
the relays, a 2% hysteresis is added to the alarm set point. This means that the alarm will remain active until the oxygen
reading has fallen 2% below the alarm set point (high alarm) or risen 2% above the alarm set point (low alarm) after the alarm
was activated. The timeout feature is useful while replacing the oxygen sensor or during calibration when the oxygen reading
might well rise above the alarm set point and trigger a false alarm.
Note: When making connections the user must decide whether to configure/connect Alarm 1 and Alarm 2 in failsafe mode
(Normally Open – NO – where the alarm relay de-energizes and closes in an alarm condition) or non-failsafe mode (Normally
Closed – NC – where alarm relay energizes and opens in an alarm condition).
Procedure: Advance the cursor (*) to the “Alarm” option and press the green ENTER key to accept the selection.
MAIN MENU
Sample
Span
Zero
* Alarm
System
Standby
Sample
5.00 PPM
Auto Range
85⁰F 100Kpa
0 to 10 PPM
12/31/07 12:00:00
The following menu appears: