The flow accumulation control instrument collects, displays, controls, transmits, communicates, prints, and processes various signals such as temperature, pressure, and flow on site, forming a digital acquisition system and control system. It has LCD and digital displays and is suitable for flow accumulation measurement and control of various liquids, general gases, superheated steam, and saturated steam; Can quantify the medium/Batch control (with start, stop, and reset functions), used in conjunction with various flow sensors or transmitters, can adapt to various measurement and control scenarios.

1. Unstable display value

The reason is that the wires on the printed board connecting the power ground and signal ground are too long, causing interference to enter. At this point, the input low potential terminal should be connected to the ground terminal to eliminate the influence of resistance on the ground wire.

2. Large temperature drift

Observing its display value, if the error is above 0.2% compared to the reading at room temperature, it indicates a large temperature drift. At this time, corresponding measures can be taken based on the following reasons:

a、 Find the cause of input voltage drift from the linearization circuit.

b、 The chip quality is unstable due to the A/D converter. Or there may be significant changes in the values of external resistors and capacitors, resulting in severe temperature drift in the stabilized power supply.

3. Jumping words

During the use of the flow integrator, if the fluctuation range of the last digit exceeds ± 1 word, it is called a jump word. The jumping phenomenon is generally caused by the jumping of the input voltage, which mostly comes from the linearizer. A five and a half digit voltmeter can be used to measure the input voltage of the linearizer. Based on the jumping situation and variation range, check the working condition of the voltage regulator power supply and voltage regulator in this stage, and then check whether the integrated operational amplifiers in this stage are working properly.

4. The difference between the measured value and the actual value is significant

At this point, it is necessary to carefully check whether the setting parameters of the instrument are correct, from measuring medium, compensation method to various parameters, and then check whether each signal input is normal.

5. Instantaneous quantity running large numbers

During on-site operation, the author encountered two instances of a certain brand's traffic calculator running high numbers, both of which occurred shortly after power failure and automatically returned to normal after a while. Therefore, it is necessary to ensure the normal power supply of the instrument as much as possible.