Terminal FM calibration (C0 (Pr. 900))
● The terminal FM is preset to output pulses. By setting C0 (Pr. 900), the meter connected to the
inverter can be calibrated by parameter setting without use of a calibration resistor.
● Using the pulse train output of the terminal FM, a digital display can be provided to connect a
digital counter.The monitor value is 1440 pulses/s output at the full-scale value of the monitor
description list (on page 5-199) (Pr. 54 "FM/CA terminal function selection").
Not needed when the operation panel or the parameter unit is used for calibration.
Use a calibration resistor when the indicator (frequency meter) needs to be calibrated by a neighbor-
ing device because the indicator is located far from the inverter.
However, the frequency meter needle may not deflect to full-scale if the calibration resistor is
connected.In this case, perform calibration using the operation panel or parameter unit.
In the initial setting, 1 mA full-scale and 1440 pulses/s terminal FM are used at 60 Hz.
● Calibrate the terminal FM in the following procedure.
Connect an indicator (frequency meter) across terminals FM and SD of the inverter. (Note the
polarity. The terminal FM is positive.)
When a calibration resistor has already been connected, adjust the resistance to "0" or remove
Refer to the monitored item list (page 5-199) and set Pr. 54.
When the running frequency or inverter output current is selected on the monitor, set the
running frequency or current value at which the output signal will be 1440 pulses/s, using
Pr. 55 "Frequency monitoring reference" or Pr. 56 "Current monitoring reference" beforehand.
Normally, at 1440 pulses/s the meter deflects to full-scale.
If the meter needle does not point to maximum even at maximum output., calibrate it with C0
Pulse width T1: Adjust using calibration parameter C0
Pulse cycle T2: Set with Pr. 55 (frequency monitor)
Set with Pr. 56 (current monitor)
Terminal FM calibration
(M) Monitor display and monitor output signal
8 V DC
1440 pulses/s (+)
5 - 219