30+ Years of Precision Instruments
1, PID parameter equipment
1), when temperature control effect is not ideal, PID parameters can be changed by self-tuning. It should be noted that when the load employs a multi-segment series heating configuration (such as in extrusion machinery), if one segment enters the self-tuning process, the temperatures of the adjacent segments upstream and downstream should be kept as constant as possible; otherwise, the self-tuning performance will be compromised.
2), manual setting of PID parameters:
P: is the proportional band (heating side), if the overshoot is large, the proportional band can be increased. If you want the temperature to rise more quickly, you can reduce the proportional band. Generally speaking, the better the insulation characteristics of the system, the smaller the value of P. If the insulation characteristics are worse, the larger the value of P should be.
I: for the integration time, if the temperature fluctuation is large, the integration time should be lengthened, otherwise the integration time can be reduced. In general, the more severe the system lag, the longer the integral time.
D: differential time, generally (1/5~1/4) I.
2. how to set the switching difference of the position type regulating instrument: (limited to the two-position type control instrument)
in the pure position type control mode, there must be an appropriate switching difference (also known as the switching difference or insensitive area). too small switching difference will lead to frequent action of AC contactor and reduce service life, an too large switching difference will cause the fluctuation of the controlled value to become large. In some cases (such as air conditioning temperature control), the switching difference can be used to set the controlled value stable within the set range, to avoid waste. In general, a hysteresis setting of 0.3% of the full-scale range is considered appropriate. The switching difference is evenly distributed above and below the set value, I .e. the median value of the switching difference is the set value of the God circuit. That is, in the 7000 series instrument, the set point deviation is 0%. Press the (SET) key for about five seconds, then the instrument enters the parameter setting layer. Press the (SET) key according to the setting operation flow. When the main display window changes to the "P" symbol, the secondary display window displays the switching difference value. After you reset the (SET) key with the "", "▲" and "" keys, the parameter can be input to the instrument, and automatically adjust according to the new switching difference setting value ( temperature meter The switching difference is set to about 0.3% of the full range when leaving the factory).
3. how to correct the error caused by the sensor:
in practical application, due to various reasons, the sensor cannot be installed in the ideal measurement area, and the sensor itself also has certain errors. at this time, the signal received by the instrument cannot reflect the correct value, which in some cases will lead to misunderstanding of users or affect the authenticity of measurement and control, for this reason, it is sometimes necessary to correct the displayed value. You only need to correct the set value in the lower display window according to the above method when the "SC" symbol appears in the upper main display window in the parameter setting layer according to the instrument setting procedure. After completion, press the function key again to input the corrected value into the instrument (the corrected value is 0 when the instrument leaves the factory, when using, prevent the correct instrument from being corrected to incorrect instead).
4. how can you set the upper and lower limit alarm values:
if the instrument you choose has the alarm contact output function and is temporarily unavailable, please set the lower limit alarm value to the lower limit of the instrument range and the upper limit alarm value to the upper limit of the instrument range, which can reduce the power consumption of the instrument and enable the instrument to work at a lower power supply voltage. Press the (SET) key for about three minutes. When the "ALL" symbol is displayed in the main display window, the alarm value is displayed in the auxiliary display window. You can use the "", "▲" and "" keys to change the settings at will. When the main display window displays the "AL2" symbol, the secondary display window displays the second alarm value. Due to the poor switching factor, please subtract 1 word when setting the upper limit alarm value, that is, if you want to alarm at 800 ℃, you should set the upper limit alarm value at 799 ℃; When setting the lower limit alarm value, you should add 1 word, so that the instrument can alarm in time word for word. When the measured value is lower than the lower limit alarm, AL2 light will be on and the lower limit relay will be closed; when the measured value is higher than the upper limit alarm, the AL2 light is on and the upper limit relay is closed.
