Sharing of common faults in Siemens touch screen repair

Sharing of common faults in Siemens touch screen repair
Problems that can be solved by Siemens touch screen repair include: the touch screen does not respond when powered on, the fuse burns when powered on, a blue screen appears on power on, the screen changes to a blue screen after a few minutes of power on, the motherboard is faulty, the screen is black, communication is intermittent, the touch fails, and sometimes the screen turns white Screen, touch panel failure, black screen, dead screen, power failure, LCD failure, touch panel damage, touch is normal but the motherboard program does not respond, touch is bad, touch failure; operation sensitivity is not enough, no display is displayed after power on, PWR light does not light up But everything else is normal, the dual serial ports cannot communicate, the motherboard is loose, the 485 serial port communication is poor, the touch screen does not respond when powered on, the communication is poor, the screen cannot be switched, the touch screen crashes, etc. Siemens modelsNo display repair, unclear brightness repair, black screen repair, flowery screen repair, white screen repair, LCD screen display vertical bar repair, LCD screen display horizontal bar repair, LCD screen display multi-screen repair, and LCD screen display difficult and miscellaneous problems. It can be repaired, the touch screen communication cannot be repaired, the touch screen does not move halfway when it is turned on, repairs cannot be entered into the program when the power is turned on, the indicator light does not light up repairs, the touch screen crashes repairs, the lamp does not light up repairs, the touch screen glass is broken repairs replace the touch screen touch offset repairs, The touch screen cannot be repaired by touching, half of the touch screen can be touched and the other half cannot be repaired by touching, the touch screen cannot be calibrated and repaired, and the touch screen has no backlight repair.
IEMENS Siemens touch screen rapid repair and repair touch screen human-machine interface equipment from the early TP070, TP170A, TP170B, TP27, TP270, OP3, OP5, OP7, OP15, OP17, OP25, OP27, OP73, OP77, KTP178, KTP400, TD200, TD400 Until now, TP177A, TP177B, TP277, TP37, OP270, OP277, OP37, MP270, MP277, MP370, MP377, Mobile177PN/DP, Mobile277, KTP600, KTP1000, KTP1200, SIMATIC HMI Comfort Panel series, SIMATIC Thin Client series and
(1) Fault 1: Touch deviation
Phenomenon 1: The position touched by the finger does not coincide with the mouse arrow.
Reason 1: After installing the driver, when correcting the position, the center of the bullseye was not touched vertically.
Solution 1: Recalibrate the position.
Phenomenon 2: The touch in some areas is accurate, and the touch in some areas is biased.
Reason 2: A large amount of dust or scale accumulates on the sound wave reflection stripes around the surface acoustic wave touch screen, which affects the transmission of sound wave signals.
Solution 2: Clean the touch screen. Pay special attention to cleaning the sound wave reflection stripes on the four sides of the touch screen. When cleaning, disconnect the power supply of the touch screen control card.
(2) Fault 2: The touch screen does not respond to touch
Phenomenon: When touching the screen, the mouse arrow does not move and does not change its position.
Cause: The reasons for this phenomenon are as follows:
① The dust or scale accumulated on the sound wave reflection stripes around the surface acoustic wave touch screen is very serious, causing the touch screen to fail to work;
② The touch screen fails;
③ The touch screen control card fails;
④ The touch screen signal line is faulty;
⑤ The serial port fails;
⑥ The operating system fails;
⑦ Touch screen driver installation error
Solutions to common faults in Siemens touch screens
Solutions to common faults in Siemens touch screens
1. The fault information of single-phase or multi-phase fault is displayed as “inveter u” or “inveter v or w”. The reason is that the single-phase or multi-phase inverter fails. If the peak current of a switch tube is i>3inrms, inrms is igbt. This situation will occur if there is a problem with the rated current of the inverter, or there is something wrong with the auxiliary power supply of one phase of the gate of the inverter. After this kind of fault occurs, it can cause a short circuit at the output end of the frequency converter, or it can also cause the motor to vibrate significantly due to incorrect controller settings. There are generally two situations during maintenance:
(1) Trigger board failure When the Siemens inverter performs pulse width modulation, the duty cycle of the pulse series is arranged according to the sinusoidal law. The modulation wave is a sine wave, and the carrier wave is a bipolar isosceles triangle wave. The intersection point of the modulation wave and the carrier wave determines the pulse series of the inverter bridge output phase voltage. The door control panel is realized through a large-scale integrated IC (ASIC), which includes a digital frequency generator with a resolution of up to 0.001hz and a maximum frequency of 500hz and a pulse width modulator that generates a three-phase sine wave system. This The modulator operates asynchronously at a constant pulse frequency of 8khz. The voltage pulses it generates alternately turn on and off two switching power devices on the same bridge arm. If this circuit board fails, it will not be able to generate voltage pulses normally, and the board needs to be replaced and repaired.
2 Inverter device failure The inverter device used in Siemens inverters is an insulated gate bipolar transistor – igbt. Its control characteristics are high input impedance and very small gate current, so the driving power is small and it can only work in the switching state. Cannot work in magnified state. Its switching frequency can reach very high, but its antistatic performance is poor. Whether the igbt component is faulty can be measured with an ohmmeter. The specific steps are as follows:
●Disconnect the power supply of the frequency converter;
●Disconnect the controlled motor;
●Use an ohmmeter to measure the impedance of the output terminal and DC connection terminals a and d (see attached picture). Measure each test twice by changing the polarity of the ohmmeter. If the igbt of the frequency converter is intact, it should be: from u2 to a is low resistance, otherwise, it is high resistance; from u2 to d, it is high resistance; otherwise, it is low resistance. The same goes for other phases. When the igbt is disconnected, it has a high resistance value both times, and if it is short-circuited, it has a low resistance value.

3 Energy consumption resistor failure The fault message is displayed as “pulsed resistor”, which means the energy consumption resistor is overloaded. There are three reasons for this: the regenerative braking voltage is too high, the braking power is too high or the braking time is too short. The energy consumption resistor is an additional component. Since the load of textile and chemical fiber equipment is a large inertia load, a high-power switch tube and energy consumption resistor are connected in parallel to the DC part of the frequency converter to the DA wiring. Its main function is to connect the power supply Dynamically limit the overvoltage on the da line when turning on, off or loading. But when the braking current exceeds the rating, the operation will be interrupted. There are generally two situations:
(1) Energy consumption resistor failure. In the actual frequency converter, the pulse resistor is 7.5ω/30kw. After using an inverter for several years, due to the frequent starts and stops of the inverter, the resistor heated up and its resistance decreased. However, Siemens inverters have strict requirements on its resistance value, which is required to be greater than or equal to 7.5ω. Therefore, even though the resistance of the energy consumption resistor of this inverter is about 7.1ω, the above fault will occur and it will not be able to start normally. Later, I switched to a high-power resistor with a resistance value of about 8ω before I could turn it on.
(2) igbt failure. There is a fault in the igbt part of the inverter, which causes excessive regenerative feedback current and also causes overload failure of the energy consumption resistor.
4. Overheating fault The fault message is displayed as “over temperature” because the heat dissipation temperature of the inverter is too high. The heating of the frequency converter is mainly caused by the inverter device. The inverter device is also the most important and fragile component of the frequency converter, so the temperature sensor (ntc) used to measure temperature is also installed on the upper part of the inverter device. When the temperature exceeds 60℃, the frequency converter will pre-alarm through a signal relay; when it reaches 70℃, the frequency converter will automatically stop to protect itself. Overheating is generally caused by five conditions:
(1) The ambient temperature is high. Some workshops have high ambient temperatures and are too far away from the control room. In order to save cables and facilitate on-site operation, the inverter has to be installed on site in the workshop. At this time, you can add a cold air duct to the air inlet of the frequency converter to help dissipate heat.
(2) Fan failure. The exhaust fan of the frequency converter is a 24v DC motor. If the fan bearing is damaged or the coil is burned out and the fan does not rotate, it will cause the frequency converter to overheat.
(3) The heat sink is too dirty. There is an aluminum fin heat dissipation device behind the inverter of the frequency converter. After running for a long time, the outside will be covered with dust due to static electricity, seriously affecting the effect of the radiator. Therefore, it is necessary to purge and clean regularly.
(4) Load overload. The load carried by the frequency converter is overloaded for a long time, causing heat. At this time, check the electric