Problems and Solutions

Common Trouble Shooting of Thermocouple Calibration Procedures

1. Why the reference terminal displays "0" or prompts "reference end of abnormal" after starting the thermocouple program?
 ● At the First, check whether the communication between the digital multi-meter and computer, scanner and computer is normal.
 ● If the digital multi-meter has been checked, please check whether the communication settings of digital multi-meter are correct.
 ●  Whether the connection between digital multi-meter and scanner is correct.
 ● Ensure the position of front key and rear key of digital multi-meter is correct.
 ● Please test whether reference end is normal, using test software called "scanner communication test" in the "Tools" menu bar.
2. Why does not the furnace heat after starting the thermocouple program?
 ● Confirm the thermocouple calibration furnace power supply is open;
 ● Disconnect the power supply of calibration furnace; use a multi-meter to test the resistance furnace (usually about 20 Ohm), if it has no reaction, specify that verification furnace has been burnt out.
 ● If above are normal, please open the cover of the scan controller, check whether the insurance 20A is normal.
3. Why does not the desktop shortcut open, and why does not the verification record table have data after the test is completed, and why does not the verification software run some functions?
 ● Firstly, install anti-virus software on the system.
 ● If these questions still exist after installing anti-virus software, please re-install antivirus verification software.
 ● If above methods cannot solve the problem, please reinstall windows system, system but do not install a mirror version (ghost version of the system).
4. Click the desktop shortcut of thermocouple procedure and thermal resistance test procedure, why does these prompts error?
 ● This is the temporary file of the verification procedures in error, please delete the file named "thermocouple calibration.rec" in "Record" folder and then re-enter. There is an illustration of "Record" folder storage address in the above tips, and the above figure is an example of the file storage address C:\ZRJ thermal instrument calibration system V7\W Couple\Record \thermocouple calibration .Rec.
5. Why repetitiveness of the thermocouple calibration’s original data is poor?
 ● Check whether the wiring is pressed.
 ● If the thermocouple has a flange, please check whether the thermocouple wire is pressed.
6. What is the reason that temperature does not go or long-term cannot be stabilized to the specified index, jumping of table’s number, the phenomenon about constant power curve presented flickering large amplitude jumping, as Thermocouple detection timing?
 ● Check whether the choice of testing furnace in software is correct.
 ● Check whether the parameters named PID are modified.
 ● The existence of leakage about testing furnace.
        Holding the temperature of thermocouple calibration furnace at 1000 ℃for about 30 minute, the AC voltage between the reference end of the thermocouple calibration furnace and the protective grounding wire (with four more than half million digital table AC voltage profile measured) should not exceed 100V should not be more than 100V. If the voltage value is exceeded, the shell of the thermocouple calibration furnace shall be checked for proper grounding.
       If the furnace shell has indeed properly grounded, the voltage still above 100V and temperature control in the process of digital table appear obvious random jump word, serious leakage calibration furnace under the condition of high temperature, cannot be used for the calibration system. Usually, the early production or the test furnace with a long time is easy to encounter such phenomenon.
 ● The interference of digital table:
       If there is a high frequency equipment or large equipment nearby, resulted high frequency interference or power fluctuation, and then caused by several phenomenon, including that digital table appears obvious random jump word, temperature is difficult to control instability. So the digital meter can be shield (Note: digital table must have reliable grounding).
 ● It exists phenomenon leakage between channel:
      After the thermocouple is installed furnace and access scanner or controller, the scanner or controller low potential channel between any terminals and protective earth should be insulated. If the insulation is damaged, it may cause apparent random number table jump word, the phenomenon that temperature stability is difficult to control and so on. So we should identify issues wiring aspects, timely trouble shooting.
 ● Power is bad:
     At higher temperature, due to high power of regulation, the average line current is large, which is resulted in that the contact is heating, ignition, sometimes open. It affects the accuracy of the result fed to test the actual power of the furnace. It leads the temperature appearing abnormal fluctuations. It results in the power curve suddenly large and small presented substantial beating. This is due to the poor contact between thermocouple test furnace power supply circuits. The solution: carefully check all joints between furnace power supply circuit (including the guillotine switch, air switch, test furnace inside and outside the terminals, scanners terminals, the scanner internal SSR, fuse holder terminals, etc.), to find out the place that is loose, make a reliable connection again. And you can use a hand-held infrared thermometer to find the site of fever.
7. Verification metal thermocouple, the reference side processing method is "standard dual and the subject are placed in freezing tank," but test results is smaller. And its difference about it is the room temperature, and why?
This is due to wiring errors of the period of thermocouple end reference from the freezing thermostat, there were the following situations:
 ● The thermocouple reference end to the freezing thermostat is unused wire compensation, however it use ordinary copper wire.
 ● Although the subject of the thermocouple reference is used junction compensation wire, but the line is not directly reach the inside of the freezing point of the thermostat and it is to its port and with the compensation wire going through the copper freezing point lead into the inner thermostat. The one end that is close to the freezing temperature is still felt.
 ● The glass tubes used in freezing point is too thick and the end of the reference temperature is higher than zero.