What causes the weighing signal to differ from the on-site weighing display after it enters the DCS?
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What causes the weighing signal to differ from the on-site weighing display after it enters the DCS?
Is it a 4-20mA signal? Convert the weighing values on site to corresponding 4-20mA current values based on the range, and measure them with a multimeter. If the values are correct, go back to the cabinet room to check whether the channel used by the DCS card is out of range, or whether the range setting in the DCS configuration does not match the actual weighing range on site
Agree with the second floor – for many projects, the ranges on the DCS do not match those in the field; it’s necessary to first perform current conversion to confirm this.
The range is the same; measure the corresponding current value again to check
If the difference is large, there must be some problem; if the difference is small, just a few kilograms, it’s likely due to wiring losses. Some instruments can be calibrated so that their readings match
Is it a Toledo meter? It’s possible that there’s an issue with the output channel of the meter. Disconnect the wire leading to the DCS, and use a multimeter to measure the current at the terminals; generally, there are 2 channels. If there’s a problem, try using another output channel
There is always some deviation after analog-to-digital conversion. Some instruments allow the output gain to be adjusted; it is possible to fine-tune the analog value corresponding to 4 mA and that corresponding to 20 mA, which helps to achieve greater accuracy after conversion.