1. Introduction
Motor control methods can vary based on application and VFDs need three fundamental references for start/stop command, direction, and speed to be able to run the motor. These reference commands may be received via several sources namely digital I/O, analog I/O, communication protocols or the keypad of the VFD itself. In this technical note, we will set up a motor control method where we control the speed of the motor via pulse input of MS300, MI7.
1.1 Operating Principle of MI7
MI7 is a programmable digital input, and it can be programmed to receive pulse inputs. When multifunction input terminal MI7 = 0, MI7 is designated as a pulse input terminal. This pulse input is without direction command, so we need another command for direction.
1.2 Related Parameters of MI7
When we use MI7 single-phase pulse input as speed reference, we must use it with the following parameters:
Pr.00-20 = 4 (Master Frequency Command Source set to Pulse input without direction command)
Pr.10-00 = 5 (MI7 Single-Phase Pulse Input Type Selection to Pulse input) Pr.10 16 = 5 (Pulse Input Type Setting to Single-phase input)
Pr.00-04 = 22 (User Defined Multi-Function Display to Pulse input frequency) to verify if the pulse input frequency is correct.
Note about Pr.10-02: Pr.10-02 is used when we need an encoder input with a pulse train.
When Pr.10- 16 = 5, you cannot set Pr.10-02 to 5: Single-phase input (MI7) for closed-loop control
