External Relay Connections - Bacharach H25-IR Operation & Maintenance Manual

Preparing for Operation
BELOW 75% OF SP – The auto-zero function is ON when the leak-rate is below 75% of the setpoint value. If
the leak rate goes above 75% of the setpoint value, then the auto-zero function turns OFF, allowing the probe
to stay on the leak without the reading being zeroed-out.
For example: If the Setpoint is 2 Oz/yr, then the auto-zero function is ON for leaks rates that are <1.5 Oz/yr.
If the leak rate is 1.5 Oz/yr, then the auto-zero function turns OFF.
BELOW 50% OF SP – The auto-zero function is ON when the leak-rate is below 50% of the setpoint value. If
the leak rate goes above 50% of the setpoint value, then the auto-zero function turns OFF, allowing the probe
to stay on the leak without the reading being zeroed-out.
For example: If the Setpoint is 2 Oz/yr, then the auto-zero function is ON for leaks rates that are <1 Oz/yr. If
the leak rate is 1 Oz/yr, then the auto-zero function turns OFF.

2.6 External Relay Connections

The H25-IR includes four SPDT relays whose relay contacts are rated 2 A at 250 VAC (inductive) and 5 A at
250 VAC (resistive). External alarm devices (e.g., horns, bells, strobe lights, etc.) can be connected to these
relays and activated when their associated relay is energized. Refer to Section 2.4.3 Relays.
Locate the external relay connector on the rear of the unit (refer to Section 1.7.2 Rear View).
Secure the leads from the external device and its power source to the external relay connector as shown in the
example diagram below. This diagram shows a typical alarm device being connected to Relay 1. Repeat this
procedure, as necessary, for the remaining relays.

Each relay may be connected as normally open (NO), or normally closed (NC).

The relay contacts are rated 2 A at 250 VAC (inductive) and 5 A at 250 VAC (resistive).

Power for the external alarm devices is supplied from an external power source.

Jumper the 'Neutral' line of an external power source to the 'Common' terminals on the relay connector.

Connect one end of the alarm device to the appropriate terminal of the desired relay (NO or NC).

The other end of the alarm device is connected to the other leg of the external power source. For
protection, install an in-line fuse of the appropriate size and design for the external alarm device being
used.
18
Typical Relay 1 Wiring
H25-IR
Instruction 3015-5286