Relay Configuration Overview - INDIGO200SERIES - INDIGO202

Indigo 202 User Guide

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English (United States)
Document type
User guide

Indigo transmitters have 2 configurable relays (relay A and relay B). Both relays have configuration options for selecting the parameter that is used to control the relay, activation triggers, hysteresis, and error state behavior.

Figure 1. Relay Configuration Options (CO2 Probe Example)
Output Mode: Select whether the relay activates above or below a set value (or set the relay Off).
Parameter: The measurement that is used to control the relay.
Unit: Select the unit of the measurement parameter that controls the relay (for example, % if the measurement is in %CO2).
Low Trigger Level and High Trigger Level: If you want to activate the relay above or below a single setpoint without using hysteresis, enter the same value for the low trigger and the high trigger. The Output Mode selection defines whether the relay activates above or below this value.

If you want to set a hysteresis, define the limits of the hysteresis with the low and high triggers.

Error State: Select which state the relay is set to when an error occurs (on, off, or remains in its current state).

Relay State Information

Figure 2. Relay Icons on the Optional Display (Relay A Active, Relay B Not Active). When one or both relays are enabled, the relay state (active/not active) is shown on the optional display. You can also check the status of the relays in the Status view of the wireless configuration interface.

Relay Activation Setpoint and Hysteresis

You can define whether the relay is activated when the measurement falls below a set limit (Active below trigger level), or when the measurement exceeds a set limit (Active above trigger level). To prevent the relay switching back and forth when the measured value is near to the setpoint value, you can set a hysteresis with the Low Trigger Level and High Trigger Level settings.

For example, if you want the relay to activate when the measurement exceeds (Active above trigger level) 2000 units, but do not want the relay to switch off if the measurement momentarily falls between 2000 and 1980 units, set the High Trigger Level to 2000 and Low Trigger Level to 1980. With this configuration, the relay activates when the measurement exceeds 2000, but does not switch off until the measurement falls below 1980.