Chines Spindle and VFD setting of my Estops can any one help (EMI i think)

[AndyUK]

The motors, spindle, and VFD all put out quite strong and varying magnetic fields, which induce small voltages in the cables around them. The VFD can also pump electrical noise back into the mains supply, which can also cause problems.

As magicminer says, you can use shielded twisted pair cable for your E-Stop line which should help to reduce the influence of the inducted noise.

Magicminers other suggestion was to put more cable distance between the VFD and the control system power supply, which will slowly attenuate the noise. A 5-way plug doesn't really do anything - its cable length, and if possible filtering, that will impact this.

At the moment, your signal is probably on (2.5V-5V) or off (0-2.5V) - meaning the noise only has to be ~ 2.5V to cause major headaches. If you increase the voltage on this line to 12V, the noise has to be on the order of 6V to cause the same problems. If you have an oscilloscope, you could measure what the level of noise is.

[Slasher102]

i have been told that i need to put a 100nf capacitor as per the diagram and that should work,
thanks for the help i will get some two core shielded cable as well.

Cheers