VERIFYING LOAD CELL FUNCTION
Most Problems are related to LOAD CELL function.
There are several ways to VERIFY that the load cells are functioning properly. The slightest touch on the weigh bin should result in a change in the readout. If this is not the case, something is wrong. When the light touch is removed, the display should return to its starting point. If this does not happen, something is interfering with free movement of the cell or the bin. Make a careful inspection of EVERYTHING around the load cells, the hanger bolts, the weigh bin tray and the weigh bin. NOTHING should interfere with free movement.
NOTE: It is normal for load cell readout to drift several grams over time and with different temperatures. Since all the component dispenses are weighed by a single set of load cells, this drift will affect all components equally and, therefore, the ratio of the components will remain accurate. Empty weight is always TARED so each dispense is accurately measured.
The following observations will verify proper load cell operation:
When the bin is empty, between cycles, the display should read near zero. An error of several grams is not important since this empty weight reading is "tared" from all dispense readings. The "empty weight" readings should be consistently within 1 or 2 grams.
The addition of several pellets to the weigh bin should result in a change in the readout. 1/10 of a gram is about four pellets, a gram about forty. This should hold true when the weigh bin is full as well as when it is empty.
Most load cell problems are caused by interference to the movement of the load cell. The load cell must be free to respond to the weight of a single pellet as well as free to move far enough to record full load cell rated weight deflection.
If weight readout is very erratic check for damage to the load cell wires. Check for a pinched wire in the connector.
An | cell will | read high. The top | limit is | ( | 3100.0) | ||
for a GB/WSB2xx | and ( | 22444) for | GB/WSB4xx or GB/WSB9xx. | A load cell | |||
that was forced | or pried upward | to | far will read ( | 0.0). |
| ||
We supply and replace load cells in matched sets and we always include the mounting enclosures. You may remove the back plate from the enclosure for visual inspection. It is not safe to remove the load cell itself from the enclosure. To do so may stress the cell itself.
To operate with damaged load cells, see KEYPAD, *87, VOLUMETRIC.
To RECALIBRATE the LOAD CELLS, see the MAINTENANCE MANUAL.
For further information, see the next page, RAW SIGNAL READOUT, and Following page, LOAD CELL plus WEIGH BIN TEST.
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