Joined: June 11, 2007
Posts: 28
Location: Karnataka
Status: Offline
Posted:
Sep 10, 2007 - 11:13 AM
Post subject: Load cell troubleshooting
Four load cells were connected to our weigh hopper before . Recently one load cell is disconnected when we found that its ohmic value is beyond the limits.
I have observed a peculiar thing. Recently when i have calibrated the hopper, for 1000 kg weight my indicator had shown 940 kg and i hv adjusted the error using a calibration constant at the indicator itself. But when i gave the hopper to service and it is charged with material it had shown 1200 kg. And the operations people are complaining that an error of about 300 kg is there..i.e. the indicator is showing more weight than the actual.
How can it be possible even after calibration? My doubt is that when i have calibrated i have evenly distributed the weights on the hopper. But in process load cannot be charged evenly. Is it the reason for error? I feel that even though one load cell is disconnected it shouldnt effect the output of hopper aseach of the three load cells that are connected at present contribute to 1/3rd of the total output.
fundu_instru
ICE Expert
Joined: June 20, 2006
Posts: 180
Location: Singapore
Status: Offline
Posted:
Sep 11, 2007 - 02:36 PM
Questions:
1. How much accuracy is desirable ? (+/- 20 kg)
2. What is loadcell sampling rate ?
3. Any local indicator showing weight or directly connected to System ?
4. Hopper used to load with ore/coal or other things?
sirisha
ICE Student
Joined: June 11, 2007
Posts: 28
Location: Karnataka
Status: Offline
Posted:
Sep 12, 2007 - 11:11 AM
1. +/-20 kg
2. 3 mV/V
3. Yeah,Local indicator is there at control room
4. Coke hopper
fundu_instru
ICE Expert
Joined: June 20, 2006
Posts: 180
Location: Singapore
Status: Offline
Posted:
Sep 20, 2007 - 03:54 PM
sorry for late reply
check at local indicator , if any special settings in averaging ?
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