JPS598007A - Pid temperature controller - Google Patents

Abstract

PURPOSE:To prevent an overshoot which is due to a quick arrival to the target temperature with a PID arithmetic control, by delivering the output of an integrating arithmetic part with limitation. CONSTITUTION:The difference signal (a) between the temperature program signal Tp given from a temperature programmer 8 and the temperature signal Ta given from a thermometer 16 is delivered in accordance with the supplied temperature program conditions. Thus operations are carried out for integration, proportion and differentiation respectively. When the result (b) of the integrating operation exceeds a certain level and in case a maximum value limiting means 11 judges a high-speed heated equal temperature holding program by the signal (e) given from the programmer 8, the output signal (c) is limited to a fixed value. The signal (c) is added to the outputs of a proportion arithmetic part 12 and a differentiation arithmetic part 13, and the corresponding power is supplied to a heater 15.

Description

[Detailed Description of the Invention] This invention relates to temperature control, particularly rapid heating,
The present invention relates to a new improvement in temperature control that is then maintained at a constant temperature so that the target temperature is quickly reached and control is performed without overshooting or the like.

FIG. 1 is a block diagram of a conventional P temperature control device. Reference numeral 1 denotes a temperature programmer which receives temperature program conditions through a temperature program moxibustion condition input means (not shown) and generates a temperature program in accordance with the input temperature. 7 is a furnace body whose temperature is controlled, and 6 is a thermometer such as a thermocouple for measuring the temperature of the furnace body 7. 2 is a temperature difference detection circuit that detects the temperature difference between the temperature program signal Tp from the temperature programmer 1 and the temperature measurement signal Tα from the thermometer 6, and outputs a temperature difference signal α. 3 performs calculations from the temperature difference signals α to P, and outputs a signal S for driving the SCR driver 4. 4 is supplied to the heater 5 of the furnace body 7. The heater operates so that the difference signal α between Tp and Tα becomes zero by the power supplied to the heater. From P in 3, the calculation formula is as follows, where P is a proportional constant, D is a differential constant, and ■ is an integral constant. When the rapid heating isothermal holding temperature program signal TPf shown in Fig. 2 α is given, P as shown in Fig. 2
If temperature control alone is used, overshoot may occur due to a constant value of P, or it may take a long time to reach the target temperature.

The purpose of this invention is to provide an extremely effective means for quickly eliminating the above-mentioned drawbacks, and in particular, to limit the maximum value of the output of the integral term in control from P, without changing the constant from P. The present invention relates to a temperature control device that quickly reaches a target temperature without overshooting in the case of a rapid heating isothermal holding temperature program.

Embodiments of the temperature control device according to the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram of a temperature control device according to the present invention. A difference signal α between the temperature program signal Tp from the temperature programmer 8 and the temperature signal Tα from the thermometer 16 is output from the temperature detection means 9 in accordance with temperature program conditions inputted by an input means (not shown). Integral calculation section 1
01 proportional calculation section 12 and differential calculation section 13 perform normal integral calculation, proportional calculation, and differential calculation. The maximum value limiting means No. 11 uses the signal t from the temperature programmer to determine whether or not it is a rapid heating isothermal maintenance program, and in the case of a rapid heating isothermal maintenance program, an output signal is output when the result of integral calculation exceeds a certain value. Limit C to a constant value. 100℃/
In the case of a temperature raising program at a thermal rate of 7Jll, which is approximately less than mix, the result of the integral calculation is outputted as the output signal C as it is. The output signal, %C, is added to the outputs of the proportional calculation unit 12 and the differential calculation unit 3 and is input to the general-purpose OR driver 14. The SOR driver 14 supplies power corresponding to the input to the heater 15.

The maximum value limiting means 11 has the following effects in the case of a rapid heating isothermal maintenance program. At the beginning of the temperature rise, the output of the maximum value limiting means 11 increases in accordance with the integral calculation value S shown in FIG. Ru. -The force proportional calculation signal τ decreases as it approaches the target temperature. Therefore, if there is no maximum value limiting means 11, overshoot 'ff:,! ,
;-Even if we add more P, ■, and D constants, the upper row rate of the output signal to the SOR driver suddenly slows down as soon as C shown in Figure 3 reaches a constant value, causing overshoot. Defend. In addition, the temperature increase rate at the initial stage of temperature increase is higher than that of the present invention when a constant is set from P which is higher than the conventional P which does not cause overshoot in calculation, and when the temperature control according to the present invention is performed. quickly reaches the target temperature and stabilizes. The limiting value of the output C from the maximum value limiting means 11 was appropriately set to about 100° with respect to the maximum value of the integral calculation value when the target temperature was 50° C. and the temperature rose rapidly from 50° C.

In this way, in the calculation control by P, the integral calculation section 1
By outputting an output of 0 through all of the maximum value limiting means 11, the target temperature can be reached extremely quickly when performing rapid heating using a constant value from an appropriate P at a heating rate of 100°C/min or less. It is also possible to prevent problems such as overshoot. Furthermore, the temperature programmer 8, temperature difference detection means 9, integral calculation section 10.
Maximum value limiting means 11, proportional calculation section 12, differential calculation section 13
can be constructed from electronic circuits or from computers.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the configuration of a conventional PID temperature control device.
FIGS. 2(L) and 2(b) are characteristic diagrams of temperature followability by rapid heating isothermal holding temperature program and conventional P-temperature control, and FIG. 3 is a block diagram of an embodiment of the present invention. 8 is a temperature programmer, 9 is a temperature difference detection means, 1° is an integral calculation section, 11 is a maximum value limiting means, 12 is a proportional calculation section, 1
3 is a differential calculation section, 14 is an SOR driver, 15 is a heater, 16 is a thermometer such as a thermocouple, and 17 is a furnace body. Applicant Daini Sayakogo Co., Ltd. Figure 11 Sentence 21: (θ) No. 21 (b) Door closed
fj = t'

Claims (1)

[Claims] A temperature difference detection means for inputting the output signal from the temperature programmer and the furnace, an integral calculation section, a proportional calculation section and a differential calculation section for inputting the output signal from the temperature difference detection means, and the integral calculation section. a maximum value limiting means for inputting an output signal from the temperature programmer and an output signal from the temperature programmer, and a maximum value limiting means for controlling the heater of the furnace and inputting output signals from the proportional calculation section and the differential calculation section. and an SOR driver for controlling the temperature, and by making the output signal from the maximum value limiting means sufficiently smaller than the output from the integral calculation section, the start-up time for a predetermined stable temperature of the furnace is shortened. Characteristic PID temperature control device.