Relay Hysteresis; Enabling Modbus Tcp/Ip On Touchscreen; Figure 24 Behavior Of Relay That Activates Above Limit, With Hysteresis - Vaisala Indigo 500 Series User Manual

6.4.3 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 off
too frequently.
When hysteresis is used, the relay activates at the defined limit, but does not switch off
immediately when the measurement moves back to the other side of the activation limit.
Instead, with hysteresis, the relay remains active until the measurement crosses the relay
activation/deactivation limit and the additional buffer value.
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6.5 Enabling Modbus TCP/IP on touchscreen
1. Select Menu > Transmitter > Network.
2. Make sure that Network off/on is set on, and that the network settings are set correctly.
3. Select Menu > Outputs > Modbus TCP/IP.
4. In Modbus off/on, set Modbus on.
More information
‣ Modbus overview (page 61)
Chapter 6 – Configuring transmitter using touchscreen display
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Figure 24 Behavior of relay that activates
above limit, with hysteresis
1 Measurement goes above the relay
activation limit (solid line —) and the
relay activates.
2 Measurement falls below the activation
limit, but stays above the hysteresis
limit (dashed line - - -). The relay
remains active.
3 Measurement falls below the hysteresis
limit and the relay switches off.
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