Analytical-industries GPR-3100 Series Oxygen Purity Analyzer Manuel d'utilisateur télécharger pdf (Page 18)

Advanced Instruments Inc.

5 Operation

GPR-3100 Rev 2/05 11

Output Connections

As illustrated above the sensor, alarm relays and signal output connections are hard wired to screw type

terminal blocks located at the rear of the analyzer.

1. Use a small bladed screwdriver to loosen the appropriate terminal screws as illustrated above.

2. Strip the wires of the cable no more than 3/16 inch.

3. To connect to an active relay or “fail safe”, connect the live cable to the common terminal C and the

secondary cable to the normally open NO terminal.

4. To break the connection upon relay activation, connect the secondary cable to the normally closed NC

terminal.

5. Insert the stripped end of the cables into the appropriate terminal slots assuring no bare wire remains

exposed that could come in contact with the back panel of the analyzer enclosure.

6. Tighten the terminal screws to secure the wires of the cable.

Danger: While connecting the cables to the relay terminals, ensure there is no voltage on the cables to

prevent electric shock and possible damage to the analyzer.

Caution: Assure the stripped wire ends of the cable are fully inserted into the terminal slots and do not

touch each other or the back panel of the analyzer enclosure.

Alarm Relays

The four alarm circuit connectors are spring loaded terminals for making connections to internal alarm

relay contacts.

Alarm 1 and Alarm 2 - Represents two threshold type alarms that can be set and configured in the field

from the analyzer’s display menu layout in Appendix A&B, Alarm menu as follows:

Establish independent set points

Either Hi or Lo

Either On or Off (enabled or disabled)

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.

Aside from being totally defeated in the Off mode, 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).

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Analytical-industries GPR-3100 Series Oxygen Purity Analyzer Manuel d'utilisateur Page 18