VFD will not start spindle when using controller

We have recently built a control box using components from Maker Store in Australia. The controller is an E5X MCS T4.1that is connected to a Folinn BD600 2.2kW VFD running a 2.2kW water cooled spindle.

When the VFD is set to operate from the built in control keypad, the spindle runs and is fully adjustable with the potentiometer. However, when the VFD is set to run from an external terminal, the spindle will not start.

We are using IOSender as the software so we set the speed to 24000RPM and select the CW radio button and the display on the VFD indicates that the spindle is running at 400Hz but the spindle is not running at all. Measuring connections and voltages across the VFD input terminals we have found that the two ACM (Analog Common) and the two DCM (Digital Common) terminals are all connected to earth. The digital control wire connected to terminal S1 reports a consistent voltage of 24V across DCM and is assumed to enable the spindle. The analog control wire connected to the AI1 terminal reports varying voltages between 0-10V across ACM and is assumed to control the speed of the spindle. Everything seems to be working correctly except the spindle will not start.

Does anyone have any suggestions about where the problem may lie?

 

Thanks for your suggestion Lee. I am not sure I understand what you are referring to when you say "$spindle/type". In my GRBL settings I have $9 that is commented as "PWM Spindle" and the setting is $9=1. Assuming that it is a boolean value then my settings have declared that I am using a PWM spindle. I did try changing this to $9=0 because the PWM 5V output terminals on the E5X MCS T4.1 are not being utilised. However, changing $9=0 made no difference. The spindle still would not start. The analog control of the VFD is connected to the Spindle Analog 0-10V output of the E5X MCS T4.1.