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The Changhui YR-RJDP series of high-performance multi-stage programmable temperature controllers are suitable for systems that require high-precision, multi-stage curve-based control for heating and cooling. They can carry out control in accordance with the requirements of the production process, following specific curves. The PID control for temperature regulation features multiple stages, with independent PID parameter settings for each stage, independent power limiting for each stage, independent setting of operating time for each stage, as well as a platform operation mode. This setup helps to significantly reduce issues such as temperature overshoot. The controllers offer flexible curve control capabilities, allow real-time monitoring of the operating time and status of each curve segment, and include various event input functions. Through the various curve control output functions, it is possible to achieve functions such as curve control pause, curve control reset, and curve control stepping, as well as a seamless switch between manual and automatic modes. http://yunrun.com.cn/upload/201907/21/201907212012440725.png 1. Market background of the product: A single-crystal furnace is a device that operates in an inert gas environment (primarily nitrogen or helium), where graphite heaters are used to melt polycrystalline materials such as polysilicon, in order to grow defect-free single crystals using the Czochralski method. The parameters that need to be controlled in a single-crystal furnace include the crystal diameter, temperature (power), raw material (silicon), leakage rate, and the quality of argon gas. Among these, the accuracy of temperature control is a key factor that determines whether a crystal can be formed successfully. The YR-RJDP series of high-performance, multi-stage programmable temperature controllers, which incorporate 2-degree-of-freedom PID control as well as PID control algorithms such as Ra-PID (RationaLOOP PID) and Just-FITTER, play an important role in the temperature control of single crystal furnaces. 2. Main technical principles of multi-stage programmable amplitude temperature controllers: ① The software for the YR-RJDP series of multi-stage programmable temperature controllers utilizes PID control algorithms such as Ra-PID (RationaLOOP PID) and Just-FITTER. It automatically tracks changes in measurement values upon power-up, and through a functional relationship between time and the set control values, it enables temperature regulation by increasing, maintaining, or decreasing the temperature in various stages. ②Based on the programming production process curve, functions such as stepping, jumping, stopping, and resetting of the curve can be implemented. ③In the overall temperature regulation of the single crystal furnace, the product is primarily responsible for precise temperature control. ④2-degree-of-freedom PID control ⑤ Independent segmental limiting function: Every programmable thermostat manufactured by a company comes equipped with an output limiting function (with the same limiting value set for all program segments); however, Changhui’s multi-segment programmable thermostats feature independent segmental limiting (that is, each program segment has its own output limiting function) ； It is particularly suitable for applications where high temperature control accuracy is required. This approach is useful for protecting the heating elements, meeting process control requirements, and controlling temperature overshoot, making it especially suitable for industries with high demands for temperature accuracy. ⑥Platform operation function: The platform operation function is one of the key technical advantages of Changhui’s multi-stage programmable temperature controllers! The multi-stage programmable temperature controllers from various manufacturers allow for manual control of functions such as “start,” “stop,” “reset,” and “step” using the buttons on the instrument panel. Building on this foundation, CHANGHUI INSTRUMENTS has developed a more reliable and intelligent multi-stage programmable temperature controller platform with the following features: A. PV wait function. a. The operating time for each program segment of the multi-stage programmable temperature controller can be set by the user according to the actual process requirements, and the instrument operates in accordance with these preset times. If an anomaly occurs in the process control, resulting in the actual temperature not reaching the target value specified for that particular program phase even though the running time for that phase has elapsed, instruments from other manufacturers will automatically proceed to the next program phase. To resolve this issue, it is necessary to manually set an appropriate running time for that program phase, so that the temperature meets the process requirements before moving on to the next phase; otherwise, the temperature control will not satisfy the process requirements. “The “PV wait function” solves this problem well: for the heating phase, one can choose to operate the program based on time, or based on PV ； During the heating phase, the \"PV waiting function\" takes care of issues resulting from improper setting of the program time; the instrument automatically increases the time or deducts excess time until the PV reaches the target temperature, after which the instrument proceeds to the next stage of the program. b. For both the heating phase and the cooling phase, the user only needs to set a value greater than zero for the program time; there is no need to worry about whether that time is sufficient or not ； c. The insulation section shall operate strictly according to the set time. B. Function to start measurement from any segment: The CHANGHUI multi-segment programmable temperature controller allows the instrument to automatically start from the PV value at the time of power loss, in any program segment; at this point, SV = PV in the display. This eliminates the need for users to manually skip the already executed program segments, and the running time for that segment is automatically reduced by the time it has already been in operation. C. The instrument automatically identifies whether the process is one of heating or cooling. A. Throughout the entire program sequence, the instrument automatically determines whether the control system is in the heating or cooling mode; as soon as the PV value reaches the target temperature for the next stage of the program, the operation proceeds to the next stage, even if the programmed time has not yet elapsed. This facilitates the effective improvement of the operating efficiency of the control system. b. The Changhui multi-stage programmable temperature controller can automatically determine whether the control process is in the holding phase or the heating phase; during the holding phase, it operates strictly according to the set time. ⑦The open instrument parameter storage function allows for the backup and restoration of the parameters of the Changhui multi-stage programmable temperature controllers that have been adjusted (parameters other than those set at the factory). For equipment manufacturers, backing up these adjusted parameters on-site can reduce the workload associated with after-sales service. a. Specific steps for backup: Press the SET key for two seconds to enter the menu, set the LOC parameter to 0, then exit the menu to view the status ； Press the SET button again for two seconds to enter the menu; only a few on-site parameters will be displayed at this point – set LOC to 202 ； The screen will flash for 1-2 seconds, indicating that the parameter backup has been completed ； b. Restore the backed up parameters: Press the SET key for two seconds to enter the menu, set the LOC parameter to 0, then exit the menu to view the status ； Press the SET button again for two seconds to enter the menu; only a few on-site parameters will be displayed at this point – set LOC to 303 ； The screen will flash for 1-2 seconds, at which point the restoration of the backed up parameters is complete. ⑧It has a function to restore settings to their factory defaults. In actual use, the parameters may get messed up, and in such cases it is possible to reset the control parameters to their factory settings. First, press the SET button for two seconds to enter the menu, set the LOC parameter to 0, and then exit the menu to see the new settings ； Press the SET button again for two seconds to enter the menu; only a few on-site parameters will be displayed at this point. Set LOC to 404, and the screen will flash for 1-2 seconds, indicating that the parameters have been restored to their factory settings. 3. Applications of multi-stage programmable temperature controllers: The schematic diagram for the temperature control of single-crystal growth processes using Changhui YR-RJDP series high-performance multi-stage programmable temperature controllers is shown below: http://yunrun.com.cn/upload/201909/21/201909211827461930.png Circuit description: The AC power supply is stepped down using a transformer; the output voltage is 25V and the output current is 28A ； MJYD-JL-75 is a thyristor intelligent module that includes a thyristor and a phase-shifting control circuit; it can deliver a maximum voltage of 450V and a maximum current of 75A ； L1 is the overcurrent protection fuse ； RSV is an overvoltage protection RC component ； RW refers to the electric furnace wire ； The YR-RJDP multi-segment programmable temperature controller outputs a current of 0-10mA; after passing through a 1K resistor, this current is converted into a DC voltage of 0-10V, meeting the input voltage requirements of thyristor modules. ◆Main control device: CHANGHUI YR-RJDP temperature controller. ◆ Auxiliary devices: thermocouples, thyristors, solid-state relays, overvoltage protection capacitors and resistors, etc. Based on the characteristics of temperature control in single-crystal furnaces, the process curves for the CHANGHUI YR-RJDP series of high-performance multi-stage programmable temperature controllers are set as follows: Curve number, Set value (°C), Time, Limit value, Remarks. Stage 1: C01=25, t01=60, r=100 – Start heating from room temperature of 25.0°C; heating time is 30 minutes, with power output set at 100%. Stage 2: C02=255.0, t02=120, r=100 – Heating time is 30 minutes, with power output set at 100%. Stage 3: C03=255.0, t03=120, r=30. Stage 4: C04=455.0, t04=90, r=30. Stage 5: C05=455.0, t05=300, r=30. Stage 6: C06=825.0, t06=8640, r=30. Stage 7: C07=825.0, t07=8640, r=30. Stage 8: C08=825.0, t08=8640, r=30. Stage 9: C09=825.0, t09=8640, r=30. Stage 10: C010=825.0, t010=4320, r=30. Stage 11: C011=825.0, t011=360, r=30. Stage 12: C012=355.0, t012=600, r=30. Stage 13: C013=25.0, t013=-121, r=30. Testing with the above set parameters shows excellent control performance, with a control accuracy of up to ±0.5°C. Since the Changhui YR-RJDP series of multi-stage programmable temperature controllers were adopted as the core control system, the cadmium telluride mercury single-crystal furnace has been operating well without any failures to date, and they can fully replace imported control instruments. Whether considering the actual operating conditions or the cost-performance ratio, choosing the YR-RJDP multi-stage programmable temperature controller can indeed fully meet the requirements. Source: Thermostat http://yunrun.com.cn/product/list_0_3.html