When ever I Run a VFD or a Welder near the unit I experience noise. Has anybody experienced this, and or know how to fix it?

Good morning shewoo3,

Not surprised. Both these devices put out a lot of electrical noise, both will feed noise into the power supply they are connected to.

Please remember that the dataTaker range are precision measuring devices that can measure signal down to less that 1 millionth of a Volt so noise can affect you readings.

Steps to take to reduce the noise.
1/ Make sure the power supply o the dataTaker is clean. Try powering the dataTaker from a different power circuit, if you can't then try running the dataTaker from a large battery or using a power supply filter that will provide a clean power supply for the logger.

2/ EMF.
Make sure you use shielded twisted pair wiring for all signal wires. Make sure the shield is connected at one end only
This is especially true for thermocouples. A 1 Deg C change on a K type thermocouple is about 0.04 mV so it doesn't take much EMF interference to blow your thermocouple reading

Basically you need to use good wiring practices to reduce the amount of noise.

Cheers

Roger