1, determine the fault within the instrument or outside the instrument
Digital display regulator external wiring power, input signals and output signals, so when it is found that there is an abnormal phenomenon, you should first use a multimeter to test the rear terminal signal, which should be within the required value of the instrument. For example, when the meter power is not displayed, first check whether the power supply of the meter is abnormal. If it is normal and the meter still has no display, the internal power supply or related components of the meter may be determined to be damaged; when there is an overflow or a jump, the measurement can be measured. Whether the input signal has an open circuit or bad contact phenomenon. If an open circuit is detected, the fault occurs outside of the table. The open circuit of the signal can be found and can be normal after being eliminated. When the measured temperature is lower than the given value and the loop current meter is still zero , Can use the multimeter to measure the output signal of the rear terminal of the meter, normally it should be 10mA. If there is not, it means that the meter itself has problems. If there is, and the loop current is still not indicated, it can be concluded that the fault occurs outside the meter, that is, the supporting ZK -1 There is a problem with the thyristor voltage regulator or ammeter that can be further searched and judged. By checking the signal on the rear terminal of the meter, it can be determined whether the fault is inside or outside the meter. When it is confirmed that the fault occurs within the meter, the fault can be further judged based on the fault phenomenon. The digital display of the fault is eliminated in the specific part of the meter.
2, digital display regulator common faults and causes and troubleshooting
Faulty as digital display regulator Troubleshooting:
2.1 Symptoms - Digital instability (hops)
1) bad instrument grounding;
2) The power supply is unstable;
3) Power transformer shield open circuit;
4) The internal reference voltage and negative power supply have a fault;
5) Potentiometer bad contact;
6) 7107 damage;
7) The power supply filtering regulator is not good;
8) The room temperature compensation circuit and the reference power supply have bad foundations;
9) Automatic zero circuit damage;
10) Welds or connectors in the contacts, connectors or components in the watch;
11) The noise in the integrated op amp is too high.
2.2 Symptom - Output is 0mA
1) Output transistor damage;
2) The integrated op amp output is negative potential;
3) The bridge power supply is damaged or its circuit connection is open;
4) Output transistor emitter resistance or lead open circuit;
5) The output connection is open.
2.3 Failure phenomenon - output is 10mA
1) Output transistor breakdown;
2) The integrated op amp output has a positive potential to turn on the transistor;
3) Damaged integrated amplifier.
2.4 Symptom - oscillating output Digital display controller troubleshooting
1) Excessive external interference;
2) The bridge power supply is unstable;
3) Welds on the device or solder joint;
4) poor connector contact;
5) The internal noise of the integrated op amp increases;
6) The power supply voltage is too low;
7) Output transistor characteristics are not good.
2.5 Symptoms - The monitor is off
1) The power transformer is damaged or the connection is open;
2) Fuse blown (open circuit);
3) Digital panel meter power connection open circuit;
4) The LED display is damaged.
2.6 Failure Phenomenon - Show Overflow
1) The input signal line has open circuit in the table part;
2) Damage to the amplifier power supply;
3) Integrated op amp damage;
4) 7107 damage;
5) The digital panel input is open.
2.7 Symptoms - only display "000
1) Signal conversion part of the bridge power supply is damaged;
2) Damage to the amplifier power supply;
3) 7107 damage;
4) The integrated op amp is damaged.
2.8 Failure phenomenon - Incomplete display
1) The LED display is damaged;
2) 7107 damage;
3) There is an open connection between the LED and 7107.
Troubleshooting method: When the above causes are determined, the damaged components are repaired. If they cannot be repaired, they can be replaced.
Digital display regulators can quickly and accurately measure and display temperature values ​​and provide data information for print recording and data processing. With the development of science and technology, digital display regulators produced by China Instrument Electronics have been widely used in various fields of scientific research and production. The instrument will inevitably appear in one way or another in transportation, storage and use. This article briefly describes its troubleshooting, steps and troubleshooting methods for reference by professionals. When the digital display controller used on the device is malfunctioning (damaged), the instrument maintenance personnel should not blindly repair it. According to the fault phenomenon of the instrument, first determine the approximate location of the fault, and then carry out targeted testing and repair of digital display control. Troubleshooting.
Henan Zonghai Plastic Industry Co., Ltd. , https://www.hnzonghai.com