First, conduct the appearance inspection of the electronic scale under the condition of power failure, and check whether the shell, switch and keyboard of the instrument are normal, and whether the instrument and the scale body are open-circuited. Or the scale body is faulty, so that the fault location can be quickly and accurately found. Let’s take a look at the electronic weight scale fault maintenance, health scale maintenance guide!
Troubleshooting of electronic weighing scales 1. No return to zero (no return to zero, no weighing)
a Check whether the output signal value of the sensor is within the standard. (A/D’s total enlargement code/use inner code range/base code range)
b is not within the standard, please refer to item 10 for compensation.
cIf it cannot be compensated, please check whether the sensor is defective. (Please check according to item 8)
d Please follow the instructions in the manual for weight calibration.
2. Inaccurate weighing
a Observe whether the internal code value is stable, whether there is friction in various parts of the sensor, whether the regulated power supply is stable, whether the op amp circuit is normal, and whether the circuit board of the A/D circuit has Foreign matter, whether the feedback resistor/capacitor/filter capacitor is defective or leaks.
bCheck whether the sensor output signal value is within the standard.
c is not included in the standard, please refer to item 10 for compensation.
d Use weights to test whether the four feet of the weighing pan are evenly weighed. (If it is not average, please refer to the ninth item to grind the scale)
ePlease follow the instructions in the manual to do the weight correction.
3. Unable to boot
a Please make sure it is not caused by the fuse, power switch, power cord and voltage switch.
bCheck whether the transformer has AC110/220 input and AC18V output.
cPlease remove the battery and turn it on with AC power to find out if the battery voltage is insufficient. (Measure the battery voltage, it should be higher than 6V, please charge if it is lower than 5.5V, and please replace the battery when it is fully charged and runs out of power soon).
4. Poor display
a Connect the normal LCD pins in parallel with the maintenance scale LCD by hand, and then turn on the machine to observe whether there is the same bad condition on the normal LCD. If not, it can be concluded that the LCD is bad .
bCheck the CPU pins for oxidation, cold welding or short circuit.
C Check whether the pins and holes of the LCD are oxidized, cold welded or short-circuited.
d Check whether the line between CPU and LCD is open.
5. Bad keys
a Please update the K/B test first. If the new K/B function is normal, it can be judged as bad K/B.
bMeasure whether the line between K/B and CPU has open circuit and cold welding.
cCheck whether the K/B feet have poor contact.
d Measure whether the diodes on the K/B and CPU loops are short-circuited or open-circuited.
6. Unable to scale to full load
a Check whether the sensor output signal value is within the standard.
b is not included in the standard, please refer to the tenth item for compensation.
cIf it cannot be compensated, please check whether the sensor is defective. (Please check according to item 8)
d If it is unstable or cannot be compensated after compensation, please replace the sensor.
eCheck if there is no interference with wiring or protective devices inside.
f Whether the battery voltage is above 6V.
gReplace the L/C to test if the sensor is bad.
7. The battery cannot store electricity
a Please make sure it is not caused by the fuse, power switch, power cord and voltage switch.
bCheck whether the transformer has AC110/220 input and AC18V output.
cRemove the battery connected to the PIN on the board, and measure whether the charging voltage of the machine board is about 7.2V. If it is insufficient, please check the power supply circuit.
d Check the machine version, whether the diode near the PIN is inserted at the input end of the transformer is normal.
eReplace the battery.
8. Determination of bad sensor
a static measurement method: use the ohm gear of the three-use meter to measure the sensor’s E+ to S+, S- (or E- to S+, S- is also acceptable) Whether the resistance value is the same, generally speaking, the error needs to be compensated if the error is above 0.5Ω. If the error is too large (above 2Ω), it is recommended to replace the L/C.
b Dynamic measurement method: Connect the sensor wiring to the motherboard correctly, and use the DCV file of a digital meter (more than four and a half digits) to measure the voltage of S+ to ground and S- to ground Whether they are equal (preferably 0 error), if they are not equal, sensor compensation is required.
9. Adjustment of angular coupling difference (single sensor)
a First perform weight correction.
bMeasure the four corners of the weighing pan with the full 1/3 weight to see the displayed value.
cUse a file to sharpen the side with the lowest scale value in the 1~4 corners, and then press to return to zero. (When grinding the scale for the first time, please test its strength with a small force test to avoid damage to the sensor)
d Repeat 2~3 actions until the four corners of the weighing pan are based on the center The error is within ±1 hop, and then the weight correction can be done.
eIf the error of the four corners of the weighing pan is too large, and it is still too large after grinding the scale, it means that the sensor is faulty, or the method of grinding the scale is wrong.
f When grinding the scale, pay attention to the sensor specifications. The lighter the full load, the lighter the grinding force.
10. Sensor compensation
a If the output signal of the sensor is too high, please add a resistor (50K~2.2MΩ according to the situation) to make the signal between “E+S-” of the sensor to make the value to the normal range (resistance Lower value = lower sensor output signal).
bThe output signal of the sensor is too low or -ERR, please add a resistor (50k~2.2MΩ according to the situation) between the “E+~S+” of the sensor to make the signal value within the normal range (the higher the resistance value is, the more Low = higher sensor output signal).
Health Scale Maintenance Guide How to repair the broken electronic scale sensor
1) Open the upper cover of the sensor (damaged), lift the weighing platform with a jack, and remove the ground wire of the sensor.
2) Open the junction box and disconnect the damaged sensor cable from the junction box. Pull out the cable at the sensor end. Note: When pulling out the wire, attach a lead wire to pass through the scale body, so that when the new sensor is replaced, the cable can pass through the scale body and enter the junction box.
3) Refer to the method in the second item above, and pass the sensor cable through the scale body into the junction box.
4) According to the wiring diagram, fix each core wire of the cable on the corresponding terminal of the junction box.
5) Loosen the jack, put the weighing platform flat, and cover the cover.
6) After replacing the sensor, the truck scale must be reset and calibrated.
7) After the sensor is installed, its redundant cables should be bundled and placed in bundles, and should not be placed directly on the foundation ground.
8) In order to ensure the consistency and interchangeability of the sensor, the sensor cable shall not be cut off at will.
9) During the installation and disassembly process, there should be no scratches or bumps on the sensor, and the cables should be protected.
The electronic scale has the following phenomena, which should be suspected to be the fault of the load cell:
(1) The electronic scale does not display zero, and the display screen keeps flashing.
(2) After the electronic scale displays zero, the weighing number will not be displayed when adding and placing weights.
(3) When the electronic scale is empty or loaded, the displayed numbers are unstable, drift or jump.
(4) The weighing of the electronic scale is inaccurate, and the displayed weighing number is inconsistent with the number of added weights.
(5) The repeatability of the electronic scale is not good. If the same weight is added, sometimes the weighing is accurate, and sometimes the weighing is inaccurate.
All of the above phenomena may be caused by a broken electronic scale sensor. The sensor that needs to be judged is removed from the system separately, and the input impedance and output impedance are measured respectively. The normal value of input impedance is 380Ω, and the normal value of output impedance is 350Ω. If the measured data is not within this range, the electronic weighing sensor is broken. If there is an open circuit in the input impedance and output impedance, you can first check whether the signal cable of the sensor is disconnected. When the signal cable is in good condition, the strain gauge of the sensor is burned, which is usually caused by a large current entering the sensor.
When the measured input impedance and output impedance are unstable, it may be that the insulation layer of the signal line is broken, the insulation performance is reduced, or the sensor is damp, so that the bridge circuit and the elastomer are poorly insulated. The zero point output signal value of the sensor is generally between (-3mv ~ 2mv). If it is far beyond this standard range, it may be that the sensor is overloaded during use, causing plastic deformation of the elastomer, making the sensor unusable. If there is no zero-point signal or the zero-point output signal is very small, it may be caused by the fact that the strain gauge in the load cell has fallen off the elastic body or the scale body is supported by a support.
What should I do if the electronic scale does not display
When there is a problem that the electronic scale does not display, the elderly can first check whether the battery of the scale body has electricity and whether the internal circuit of the scale body is worn; secondly, refer to the manual to do Preliminary fine-tuning to see if the display is normal; finally, to ensure that the electronic scale does not have the above problems, you can consult the after-sales service or the professionals of the local quality inspection department.
There are several reasons why the electronic scale does not display:
1. Power supply problem: low voltage.
2. The power switch problem.
3. The electronic scale shows that the drive circuit is short-circuited or open-circuited.
4. The display screen [LED/LCD] is faulty or the printed circuit is short-circuited or open-circuited.
5. The single-chip microcomputer circuit problem [I/O port] has short circuit or open circuit. Or program problems, pay attention to the crystal oscillator problem, it can be replaced,
6. There is a problem with the reset circuit of the microcontroller.
In addition to accurately weighing the height and weight of the elderly, the electronic scale can also store data to help the elderly analyze health data, which is more practical than traditional scales. When the electronic scale does not show this situation, the elderly should first check the power supply, because most of them are caused by power problems.
