XMZ-101 digital display instrumentFault diagnosis approach
When measuring parameters such as temperature, pressure, flow rate, liquid level, etc., display instruments are mostly used to display control or record measurement results with recorders. When the display instrument malfunctions, its symptoms include: the instrument does not move, displays large or small, display errors are large, the instrument response is slow, and the display fluctuates greatly.
The reason why the display instrument will not operate is due to interruption or input signal interruption. This is relatively easy to check and judge. To display high or low values, it is necessary to check whether the input signal is normal. If the thermistor is open circuited, the instrument will already display high. If the display instrument has a thermocouple protection circuit, the instrument will already display a high or set temperature value when the thermocouple is disconnected. If the display is used in conjunction with a transmitter, when there is no signal output from the transmitter, the display will mostly show a small value. For large display errors, if the errors caused by measuring components are excluded, the display instrument should be calibrated locally. When the displayed value fluctuates significantly, the first thing to check is whether the wiring is loose and whether the line contact is good. If it is confirmed that there is no problem with the line, then interference should be considered.
When the display instrument shows no display or cannot work properly, the parameter setting (i.e. program setting) of the digital display instrument and paperless recorder should be considered first. Especially for newly used instruments, it is necessary to check the parameter settings of existing instruments. If the measurement or control parameters are not set correctly, the instrument cannot function properly. So when analyzing and judging faults, it is necessary to first check whether the parameter settings are correct, and then check for hardware problems.
XMZ-101 digital display instrumentExamples of fault inspection and handling
① Parameter setting of digital display instrument
Most of the digital display instruments currently in use use use microprocessors, which manufacturers refer to as smart instruments. Compared with traditional digital display devices, the major difference is that the use of smart instruments is based on parameter settings. Therefore, when judging and dealing with such instrument faults, it is important to understand the working status of the instrument, as its working status will determine whether you can perform a certain operation. Normally used instruments are usually in a basic state, and the basic state or program running state can be switched through buttons.
Due to different manufacturers and models, the parameter setting methods of digital display instruments are also different. However, due to the limited panel size of the instrument, the popular buttons for digital display instruments usually include the following four:
In the basic state, hold down the key for 5 seconds to enter the parameter setting state. In the parameter setting state, press the button again, and the instrument will display each parameter in sequence; Use the equal key to modify parameter values. Press and hold the key to return to displaying the previous parameter. Press and hold the long button to exit the parameter setting state. If there is no button operation after 30 seconds, the instrument will automatically exit the parameter setting state and return to the basic state.