FM output circuit
Pulse width T1: Adjust using calibration parameter C0
Pulse cycle T2: Set with Pr.55 (frequency monitor)
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 neighboring 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, calibrate additionally with
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.
• When Pr.291 Pulse train I/O selection = "10, 11, 20, 21, or 100", this is high-speed pulse train output for open collector
output. A maximum pulse train of 55k pulses/s is outputted.
There are two types of pulse width: "50% duty" and "fixed ON width"; this cannot be adjusted with the calibration parameter
C0 (Pr.900) FM/CA terminal calibration.
High-speed pulse train output circuit
(example of connection to pulse counter)
Pull up resistance
The pulses may weaken due to stray capacitance in the wiring if the wiring is long, and the pulse counter will be unable to recognize the pulses.
Connect the open collector output to the power source with a pull-up resistor if the wiring is too long.
Check the pulse counter specs for the pull-up resistance.
The resistance should be at 80 mA of the load current or less.
• When Pr.291 = "10, or 11", the pulse cycle is 50% duty (ON width and OFF width are the same).
• When Pr.291 = "20, 21, or 100", the pulse ON width is output at a fixed width (approx. 10 μs).
• At the "100" setting, the same pulse train from the pulse train input (terminal JOG) will be outputted. This is used when
running at a synchronized speed with more than one inverter. (Refer to
Pulse of Pr.291 = "10, 11"
Set with Pr.56 (current monitor)
Pulse of Pr.291 = "20, 21, 100"
5.11 (M) Item and output signal for monitoring