The two basic operating modes for flow switch output are hysteresis mode and window comparator mode.

In hysteresis mode, the switch will turn on when the flow is greater than the set value, and will turn off when the flow falls below the set value by the amount of hysteresis or more. For example, if the set value is 100L/min and the hysteresis value is 10L/min, when the measurement falls below 90L/min, the switch will turn off. Hysteresis mode can be selected for applications that require only one set point such as to monitor the purge of air flow in ionizer to ensure the flow rate is above specific flow rate requirement.

In window comparator mode, the switch output will turn on or off depending on whether the flow is within the range of the 2 set values, which are the lower limit and upper limit. For example, if the 2 set values are 90L/min and 120L/min, switch will turn on when the measurement is within the range of 90 to 120L/min. Window comparator mode can be selected for applications that require lower and upper limit set points such as to monitor the air flow for spray painting to prevent uneven painting due to excessive or insufficient flow rate.

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