Hitachi VFD Connection

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Hey Martin,

@MVall

Is using Forced Operator Mode as simple as …

1. wiring a shielded twisted pair cable to P24 terminal and Logic Input 1 Terminal on one side, and a, for example, 2-position 24V normally open selector switch on the other side? Leaving short bar in PLC - L position for “sourcing”, which apparently is default in EU and US, and using the internal 24V power.

yes, it is.

Here I show you an example wiring if you want to be able to override ModBus control with the “Force Terminal Mode (F-TM)” (or with “Force Operator Mode (OPE)”, in this case you simply omit SW 1 and VR 1 and use any of the Intelligent Inputs for your switch you like).

1. As you can see, in this example I left untouched the switch on Intelligent Input 1 which serves as “Start/Stop Spindle” switch when this input is programmed this way (C001 to 00). This is SW 1 in the diagram.
2. To choose a unused Intelligent Input to use it for switching to the “Force Terminal Mode” (or the “Force Operator Mode”), you are free to use Intelligent Inputs 2–6 in this example, but since Intelligent Input 6 has not dual use to expect, I chose this one in this example. This is SW 2 in the diagram.
3. Finally I showed the wiring for a speed knob for spindle speed. It is called VR 1 (VR = variable resistor, aka potentiometer). It acts as voltage divider here by providing a variable analog voltage setting to pin “O”.

If you program Intelligent Input 6 to “F-TM” and you switch it on, then the states of SW 1 (spindle running or stopped) and VR 1 (spindle override speed) will come into effect.

If however you don’t want to use “Force Terminal Mode (F-TM)” but “Force Operator Mode (OPE)” instead, which will enable to control Run/Stop and Spindle Speed from the VFD’s Front Keypad, you can simply omit SW 1 and VR 1. SW 2 will then switch the “Force Operator Mode” on (if you programmed Intelligent Input 6 to this function).

Note that this all assumes that you have set A001 (“Speed Source Selection”) and A002 (“Run Command Source Selection”) both to 03 (“ModBus (RS485)”), which means, the VFD is controlled by the CNC Controller via the ModBus serial communication (with VFD pins SP and SN connected to pins 13 and 14 on DB-25 I/O port on CNC controller). The switch SW 2, wired to Intelligent Input 6 in this example, will then, if activated, override the speed and run commands received via ModBus from the CNC Controller. For this, the Intelligent Input 6 (setting C006) has to be programmed to either 51 “Force Terminal Mode (F-TM)” or 31 “Force Operator Mode (OPE)”. If you choose “Force Terminal Mode (F-TM)”, you should also have Intelligent Input 1 (setting C001) left to default setting 00 “Forward Run/Stop (FW)” which means it will act as a switch for starting and stopping the spindle.

@MVall

So I’m guessing it wouldn’t matter which wire from VFD goes to which terminal on switch contact because it’s just opening and closing a simple circuit?

This is correct.

@MVall

I’m looking specifically at this simple selector switch (GCX3300, two-position maintained, N.O.)

This is a rather beefy switch. The smallest microswitch available would be sufficient You just switch a logical signal. But your switch is beautiful, I like it.