ZeDrive Pump Controller Signal noise

We have been using a ZeDrive for over 8 years to control a metering pump that is down stream of a weighbelt.

The weighbelt provides a 4-20mA signal as an output to the slaved ZeDrive. The 4-20 is a function of the weight on the belt and the ZeDrive is slaved to the weighbelt to proportion a metering pump for a later material add.

Proportion is the key as the weight increase the feed rate of the metering pump increases.

Well about 5 years ago we replaced a worn out ZeDrive (we had internal EPROM errors) with the new and improved ZeDrive2000 model. We were very happy with the switch as the user interface was much simpler and easily configurable for what we needed.

Anyway, the "new" ZeDrive2000 lost its EPROM and has had some sporadic problems of late. As it turns out the 2000 model is no longer available and we had to get a new ZeDrive replacement.

So we get the drive in and change all the necessary jumpers, hook up all the wiring and power the unit up. In manual everything is fine. The minute we switch to Automatic we get an error.

After speaking to the Drive people they insisted it is noise. Rechecked the wiring and everything is correct.

One possible error is the Analog out from the weighbelt is a non-isolated out. Is this my problem? Can it be fixed? Where else should I be looking?

Thanks,

J

I take it youve looked at this? http://www.zenithpumps.com/products/zedrive_troubleshooting.htm

Anyway I know nothing about your drive but I would think that noise on and current analog device might not really be the problem. But if the manufacture insists you could put a scope, using a current probe, on it and see for sure..