Emerson Micro Motion 5700 - Configure Flow Rate Switch

The signal from the mA output indicates the current state of the process:
• 12 mA: Single-phase flow
• 16 mA: Moderate two-phase flow
• 20 mA: Severe two-phase flow
6.3 Configure Flow Rate Switch
Display Menu > Configuration > Alert Setup > Enhanced Events > Flow Rate Switch
ProLink III Device Tools > Configuration > I/O > Outputs > Discrete Output > Source > Flow Switch Indication
Field Communicator Configure > Manual Setup > Inputs/Outputs > Channel x > Discrete Output x > Flow Switch
Flow Rate Switch is used to indicate that the flow rate has moved past a user-specified setpoint, in either
direction. The flow rate switch is implemented with a user-configurable hysteresis.
Typically, a Discrete Output is assigned as the flow rate switch indicator. The Discrete Output can be wired to
an external device such as a light or a horn.
Prerequisites
A channel must be configured as a Discrete Output, and the Discrete Output must be available for this use.
Procedure
1. Set Discrete Output Source to Flow Switch, if you have not already done so.
2. Set Flow Switch Variable to the flow variable that you want to use to control the flow rate switch.
3. Set Flow Switch Setpoint to the value at which the flow switch will be triggered (after Hysteresis is
applied).
• If the flow rate is below this value, the Discrete Output is ON.
• If the flow rate is above this value, the Discrete Output is OFF.
4. Set Hysteresis to the percentage of variation above and below the setpoint that will operate as a
deadband.
Hysteresis defines a range around the setpoint within which the flow rate switch will not change.
• Default: 5%
• Range: 0.1% to 10%
Example
If Flow Switch Setpoint = 100 g/sec and Hysteresis = 5%, and the first measured flow rate is above
100 g/sec, the discrete output is OFF. It will remain OFF unless the flow rate drops below 95 g/sec. If
this happens, the discrete output will turn ON, and remain ON until the flow rate rises above 105 g/sec.
At this point it turns OFF and will remain OFF until the flow rate drops below 95 g/sec.
Related information
Configure a Discrete Output
Configuration and Use Manual Configure advanced options for process measurement
MMI-20025166 March 2019
Configuration and Use Manual 107