Measurements

MicroLogic A trip unit measures instantaneous currents and stores the maximum values in maximeters.

MicroLogic E trip unit measures the same values as the MicroLogic A trip unit, plus voltage, power and energy values.

MicroLogic A/E trip unit measurements can be displayed on:

The screen of the trip unit (refer to the detailed topic for MicroLogic A trip unit, refer to the detailed topic for MicroLogic E trip unit)
An optional FDM121 front display module
A PC via the Modbus communication (COM) option (refer to the detailed topic).

The following table indicates MicroLogic A/E trip unit measurement and display possibilities.

Measurements	MicroLogic A	MicroLogic E	Displayed on:
Measurements	MicroLogic A	MicroLogic E	MicroLogic	FDM121	COM
Instantaneous currents I1, I2, I3, IN, Ig, IΔn	✔	✔	✔	✔	✔
Current maximeters I1max, I2max, I3max, INmax, Igmax, IΔnmax	✔	✔	✔	✔	✔
Demand current I1, I2, I3, IN	–	✔	✔	✔	✔
Demand current maximeters (peak demand) I1 max, I2 max, I3 max, IN max	–	✔	–	✔	✔
Phase-to-phase voltages V12, V23, V31 (3-wire and 4-wire systems)	–	✔	✔	✔	✔
Phase-to-neutral voltages V1N, V2N, V3N (4-wire systems)	–	✔	✔	✔	✔
Average voltage Vavg	–	✔	–	✔	✔
Voltage unbalance Vunbal	–	✔	–	✔	✔
Instantaneous powers P, Q, S	–	✔	✔	✔	✔
Power maximeters Pmax, Qmax, Smax	–	✔	–	✔	✔
Demand active power P	–	✔	✔	✔	✔
Demand apparent power S	–	✔	–	✔	✔
Demand power maximeter (peak demand) Pmax	–	✔	–	✔	✔
Instantaneous power factor PF	–	✔	✔	✔	✔
Active energy Ep	–	✔	✔	✔	✔
Reactive and apparent energy Eq, Es	–	✔	–	✔	✔

If no information is displayed on the screen, refer to MicroLogic Display.

NOTE:

The instantaneous currents I1, I2, I3 are also displayed by LEDs on the MicroLogic front face.
The display of the neutral current (IN) is available with MicroLogic E trip unit when the parameter Type of network has been set to 4-wire 4ct (44).
For 3-pole circuit breakers used on 4-wire systems (3 phases + neutral), terminal VN on the MicroLogic trip unit must always be connected to the neutral. If this is not done, the phase-to-neutral voltage measurements can be erroneous.

Measurement	Definition
Instantaneous current	The rms value of the instantaneous time current.
Neutral current	Available with a four-pole circuit breaker or three-pole circuit breaker with external neutral sensor.
Current maximeter	Maximum value of the instantaneous time current (refreshed every 500 ms) since MicroLogic installation or last reset.
Demand current	Mean of all instantaneous time current values over a given user-adjustable time interval (for example, 10 minutes). For more information, refer to Calculating Demand Values.
Voltage	The rms value of the voltage.
Average voltage	Average of the 3 phase-to-phase voltages V12, V23 and V31:
Voltage unbalance	Voltage unbalance on the most unbalanced phase, displayed as a percentage of Vavg. MicroLogic Etrip unit measures the maximum difference between the instantaneous time voltage of each phase and Vavg, and calculates the voltage unbalance:
Instantaneous power	P: total active power Q: total reactive power S: total apparent power P, Q and S are rms instantaneous values.
Power maximeter	Maximum value of the instantaneous time power (refreshed every 1 s) since MicroLogic installation or last reset.
Demand power	Mean of all instantaneous time power values over a given user-adjustable time interval (for example, 10 min). For more information, refer to Calculating Demand Values.
Instantaneous power factor PF	PF = P / S
Total energy	Ep: total active energy Eq: total reactive energy Es: total apparent energy