Vaisala Indigo200 - Relay Activation Options; Relay Hysteresis; Figure 18 Relay Icons on Display (Relay a Active, Relay B Not Active)

Relay state information
When one or both relays are enabled, the relay state (active/not active) is shown on the
transmitter display. You can also view the status of the relays with Insight PC software.
Figure 18 Relay icons on display (relay A active, relay B not active)
6.1.1 Relay activation options
Note that the values given must match the parameter and unit selections.
Relay activation and deactivation can be configured to happen either when the measurement
passes a single setpoint, or also when the measurement is within or outside a set range. The
following options are available:
• The relay activates when the measurement rises above or falls below a single setpoint,
and deactivates when the measurement returns to the other side of the setpoint value.
• When you set a higher value for Activate above and a lower value for Activate below, the
relay is passive when the measured value is in between the setpoints.
• When you set a lower value for Activate above than for Activate below, the relay is active
when the measured value is in between the setpoints.
For examples of dierent relay activation options, see Relay activation and hysteresis
examples (page 35).
Note that the hysteresis configuration has an eect on relay activation and deactivation. For
more information on hysteresis, see Relay hysteresis (page 34). The eect of hysteresis is also
described in the examples in Relay activation and hysteresis examples (page 35).
6.1.2 Relay hysteresis
If the measurement you are using to control the relay is likely to move back and forth close to
the activation setpoint, you can set a hysteresis that prevents the relay switching on and o
too frequently.
Indigo201 User Guide M212842EN-B
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