ABB Loadcell

'Been a while since I was involved in load cells of the strain guage Wheatstone bridge type (dunno about the ABB ones), and I think the most modern ones have their own signal conditioning in the cell. However my suggestion (for the old type) is that is your current and ammeter of the same digital sampling rate? You may not be seeing an intermittant spike in your current measurement, and I would tend to use an anologue ammeter for that - in case your not.

Sorry I can't be more helpful.

I haven't used ABB loadcells but they should operate under the same principle. I use Sartorius (which used to be Global Weighing which used to be Philips).

That spike in the excitation shouldn't be there. You didn't say how big it was though. I've got two guesses:

• You've got a loose connection somewhere between the excitation and sense terminals. If the sense lines detect a drop in the excitation, it will tell the circuit to adjust by increasing the voltage. If it's intermittent, you'll get a spike.
• Your shielding in the cables, junction boxes, transmitters, or loadcells themselves, is disconnected and allowing noise from switches, contactors, etc. to punch through. This can also happen if you've routed your loadcell cables next to high voltage lines (>220V).

You can also try replacing your transmitter with a new one just to check if the transmitter is at fault.

It is not very clear from the question how many loadcells are there in your system. If it is a single loadcell unit, check the exiter power supply, the regulator, current limitter cct and ofcource any loose contact or drysolder points in loadcell circuit. And lastly the Loadcell itself.

If it is a multi loadcell unit, straight away interchange the connections of the troublesome loadcell with another one, if the problem tranfers with the loadcell replace it, otherwise check thaat line of wirings.

PS; check the mechanical mounting also.

GOOD LUCK.