Vaisala Indigo 500 Series, User Manual

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6.4.1 Relay configuration example
This example shows how to configure a relay to activate when relative humidity
measurement from Probe 1 goes above 90 %RH, and to switch off only when the
measurement falls below 85 %RH (hysteresis). To configure the relay, use the following
values:
• Relay off/on : Set relay off to edit settings.
• Parameter : Relative humidity
• Activation : Active above limit
• Limit : 90
• Hysteresis : 5
• Relay off/on : Set relay on to activate settings.
6.4.2 Relay wiring and relay activation mode
The physical relay opens and closes the circuit depending both on the relay wiring
and the relay activation mode.
Table 8 Relay wiring: Normally open (NO)
Relay activation mode Measurement above/below
limit Relay opened/closed
Relay active above limit Above = Relay active Closed
Below = Relay inactive Open
Relay active below limit Above = Relay inactive Open
Below = Relay active Closed
Table 9 Relay wiring: Normally closed (NC)
Relay activation mode Measurement above/below
limit Relay opened/closed
Relay active above limit Above = Relay active Open
Below = Relay inactive Closed
Relay active below limit Above = Relay inactive Closed
Below = Relay active Open
Indigo 520 User Guide M212287EN-A
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