RMT Ltd. Thermoelectric Module Controller DX5100 – Table Top Quick Start User Guide RMT Ltd. Moscow 2014 Version 1.01 Controller DX5100 Table Top. Quick Start RMT Ltd. Table of Contents Features and benefits ......................................................................................................................... 3 Specifications ..................................................................................................................................... 3 Common ......................................................................................................................................... 3 Performance ................................................................................................................................... 3 Dimensions ..................................................................................................................................... 5 Thermal mounting considerations ...................................................................................................... 7 How to Get Connected ....................................................................................................................... 7 RS485 Connection .......................................................................................................................... 7 TEC Connection .............................................................................................................................. 7 Thermistor and TEC Connection .................................................................................................... 7 Power Connection........................................................................................................................... 8 Getting Started ................................................................................................................................... 9 Operation Modes ................................................................................................................................ 9 DX5100 Vision .................................................................................................................................. 10 Thermistor Settings .......................................................................................................................... 11 Procedure Description .................................................................................................................. 11 Thermistor Current Settings .......................................................................................................... 11 Choice of Thermistor Type ........................................................................................................... 13 Temperature as Function of Resistance: ...................................................................................... 13 Calibration of Temperature Measurement Channel ..................................................................... 14 Setting Alarm Limits.......................................................................................................................... 16 Setting Limits of TEC Voltage ....................................................................................................... 16 Setting Temperature Limit Values ................................................................................................ 16 PID Tuning ........................................................................................................................................ 18 PID Tuning Tips ............................................................................................................................ 18 Routine Operation ............................................................................................................................ 20 Autostart ........................................................................................................................................ 20 Mode "Program" ............................................................................................................................ 21 T-Regulation (Relay) ..................................................................................................................... 21 Constant Voltage .......................................................................................................................... 22 PID regulation (Constant Temperature)........................................................................................ 22 Monitoring ......................................................................................................................................... 23 TEC Control: DC versus PWM ......................................................................................................... 24 Page 2 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Features and benefits - Bi-directional temperature regulation (heating and cooling) of a TEC with high accuracy - Work with RTD sensor and thermistors of both NTC and PTC types (known T=f(R) resistance range 70 Ohm…996 kOhm) - One or two TECs controlled - TEC operation current and voltage range as ±4A and ±8V per channel. - PID temperature regulation mode - Constant voltage operation mode (4 wire possibility) - T-Regulation (relay) mode - Mode of temperature programming in time - DC regulation of TEC in all operation modes - Diagnostics of TEC performance by the Z-metering approach - PID auto-tuning function - Independent work without remote computer, based on preset and programmed start. - Communication interfaces USB and RS485 - Network of up to 32 Channels is available jointed by RS485 bus - Software for controlling - Protocol WAKE for user software programming Specifications Common Name Units Value Comments Yes Yes Yes Yes TEC bi-directional (heating and cooling) Operation Modes PID Constant voltage Temperature Program Т-regulation (relay) Possibility of Operation Modes Of Regulation after Restarting Local control Remote control Yes Yes Yes USB RS485 WAKE 32 (128) Communication interfaces Communication protocol Maximal number of channels in network Programmable thresholds Temperatures Max voltage Operational temperatures range Storage temperatures range Humidity Power supply °C °C % V 2 1 0…+45 -20…+60 5…95% 12 2 buttons BIN & SYM Combined by RS485 Each Channel Performance Name Maximum current Maximum voltage Maximum power Version 1.01 2014 Units Value Absolute Maximum Parameters A 4 8 V 32 W Comments Per channel Page 3 / 25 Controller DX5100 Table Top. Quick Start Name RMT Ltd. Units Value 2 Regulation channels number Parameters of TEC Voltage Regulation Voltage Range V -8…+8 Accuracy of voltage regulation mV 1 Resolution of voltage setting mV 0.13 Resolution of measurement 6 V Output ripple, not more 10 V Efficiency of converters % 85 Temperature Regulation 4-wire sensing Yes Resolution °C 0.001 Stability °C 0.005 Accuracy °C 0.5 Types of Thermosensors Platinum thermistor Pt Other types of thermistors NTC, PTC Resistance range Ohm 70…996K Mode «Program» Programs number, max 16 Program steps number, max 50 Steps number in a process 800 Program step duration, max s 65 535 Time interval accuracy s 1 Different operational modes when Yes temperature programming in time Programs cascading Yes Comments Typical values. Depend on thermistors type Known T=f(R) 0..15 0..49 Programs in series The given data are true for the ambient temperature 23±5°C and humidity 45±15% Important! The DX5100 Table Top controller is based on DC current regulation by TEC in all operational modes (See chapter “TEC Control: DC versus PWM”). Page 4 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Dimensions 3 2 1 8 4 9 6 3 2 10 5 7 1 2 3 4 5 6 7 8 9 10 11 Version 1.01 2014 11 Housing Left panel Right panel TEC2 Connecting TEC1 Connecting Indicator (LCD Display) Control buttons Power switch Power connector Connector miniUSB RS485 Connector Page 5 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. PHOENIX CONTACT Connectors MC 1,5/ 2-ST-3,81 MC 1,5/ 3-ST-3,81 1803578 - 1pcs 1803581 – 1pcs MC 1,5/10-ST-3,81 1803659 - 2pcs PHOENIX CONTACT cable housing KGG-MC 1,5/ 2 1834343 – 1pcs KGG-MC 1,5/ 3 1834356 1pcs KGG-MC 1,5/10 1834424 2pcs Page 6 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Thermal mounting considerations The DX5100 TABLE TOP controllers may generate a significant amount of heat TEC pumping power. They must be adequately heat sinked in order to prevent overheating of the controller. An external heat sinking may be necessary depending on TEC pumping power and ambient temperature. Important! Ensure adequate heat dissipation from DX5100 in order to prevent its overheating. How to Get Connected There are connection terminals on both sides of the controller. RS485 Connection Signal A of interface RS485 Signal B of interface RS485 Signal GND of interface RS485 TEC Connection Important! Ensure proper heat dissipation from hot side of your TEC by using proper heat sink and good thermal contact between TEC hot side and a heat sink Important! Any TEC must be connected according to its polarity to operate in cooling mode. Thermistor and TEC Connection DX5100 Table Top controllers have two channels for TEC control. You can run one channel only or both channels simultaneously. Important! Thermistor position must be carefully selected according to the design of an object (heat load) on a cold side of TEC, ensuring minimum possible temperature gradient between the thermistor and TEC cold side. Perfect thermal contact between the thermistor and an object (heat load) is required. The thermistor may be connected by a 4-wire or 2-wire circuit as shown on the figure below. We recommend always connect the thermistor by two twisted pairs for 4-wire circuit. 2-wire connection may be used for thermistor resistance exceeding 1000 Ohm. For this connection, correspondent connecting terminals contacts should be bridged. Version 1.01 2014 Page 7 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. to FAN if need TEC to FAN if need TEC Thermistor Recommended connections of TEC and thermistor Thermistor Connections possible for thermistor resistance exceeding 1000 Ohm Connections of TEC and thermistor to the controller Power Connection Connect the power supply having the polarity in mind. The power supply source should provide voltage 12±10% V. Power + Power Important! Power supply must be chosen based on the number and the total power consumption of the controller power boards. If the maximum power available for the control of a TEC (Imax and Umax) is less than the maximum value of the power board (boards) of the controller, the power supply block can have a lower power correspondingly. Page 8 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Getting Started You will need a PC to get DX5100 controller up and running when you switch it for the first time. After that, you may not need it in everyday use. Operation Modes There are several modes of regulation available by DX5100: Regulation is off (idle) Mode "Program" T-regulation (relay) PID regulation Constant voltage maintenance Important! Before selection of operation mode, important setting and calibration procedures must be obtained. The procedures are described below. Missing these procedures may result in permanent failures and fatal damages to controllers, TECs and objects controlled. All controllers are set to “Idle” mode before shipment. The controller must be in “Idle” mode if you set or re-set any parameter in order to exclude permanent failures and fatal damages to controllers, TECs and objects controlled during the procedure. Check operation mode carefully before starting any setting or re-setting procedure. Version 1.01 2014 Page 9 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. DX5100 Vision Install the DX5100 Vision program supplied or downloaded from the manufacturer's website http://rmtltd.ru/downloads/. Switch on your 12 V DC power supply. Indicating LED near 12 V DC input wil go red. Apply 12 V DC to DX5100 interior using 12 VDC switch on DX5100. Indicating LED will go green Connect the controller to a computer via the cable miniUSB. By default, the controller has a rate setting of 19200 kbps. DX 5100 needs one command and one noncommand interface. When you run the program, it scans the serial ports of the system and determines the command interface of the connected controller DX5100. Another COM-port is highlighted by colour next to it. This is a noncommand interface. Mark both the COM-ports and press the button «Open». Page 10 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Thermistor Settings Attention! It is strongly recommended to back up the parameters of the controller before adjusting the thermistor. See "Backup/restore of parameters". DX5100 Vision. Technical Manual. Procedure Description Select “Thermistor setting” in DX5100 VISION The thermistor setting means finding and storing parameters of the ADC channels for each thermistor in the non-volatile memory. Thermistor Current Settings Select the channel you wish to set. It is not necessary to set thermistor in second channel if you use only one channel of DX5100. If necessary, you can get the current settings of the thermistor and estimate the accuracy of measurements. Press the button «Show current Thermistor settings» The program will read from the controller the type of the function converting resistance to temperature 𝑻 = 𝒇(𝑹), and its coefficients, and will try to identify the thermistor. In that case the coefficients match with the predefined values, the screen will display the following information: Version 1.01 2014 Page 11 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. If the coefficients do not match (the sensor is unknown), the program will build the dependence of temperature versus resistance to obtain the coefficients and determine the sensor nominal (platinum sensor at Т = 0 °С, for NTC thermistor at Т = 25°С). Page 12 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Choice of Thermistor Type To simplify the setup procedure, the program offers a choice of predefined characteristics of thermistors. The list includes parameters for 4 platinum thermistors and 47 NTC thermistors with different alpha and beta coefficients. If you have chosen a thermistor from the list, you can go to the next section, "Calibration of temperature measurement channel". If your thermistor is not listed in the menu, you must use "User defined" option. The program will ask you to choose a type of function for calculating temperature and operating 1 temperature range . Temperature as Function of Resistance: The controller allows using 2 types of functions for calculating temperature versus resistance: Polynomial 5th order function: 𝑻 = 𝑨𝟎 + 𝑨𝟏 𝑹 + 𝑨𝟐 𝑹𝟐 + 𝑨𝟑 𝑹𝟑 + 𝑨𝟒 𝑹𝟒 + 𝑨𝟓 𝑹𝟓 Steinhart-Hart equation: 𝟏 𝑻 = 𝑨 + 𝑩 𝒍𝒏(𝑹) + 𝑪 𝒍𝒏(𝑹)𝟑 When Steinhart-Hart equation method is selected, you must enter 3 points of the dependence of temperature on resistance. This information is usually provided by a thermistor manufacturer. Two points should be at the extremes of working range, while the the third one - in a middle between extremes. The distance between points must be at least 10 degrees. The Steinhart-Hart equation describes NTC thermistors very well. When choosing a polynomial function of temperature calculation you must enter correspondent coefficients, also available from thermistor manufacturer. 1 The ambient temperature must fall within the operating temperature range, but if you are sure it does, you can disable the checking of this condition. Version 1.01 2014 Page 13 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. Results of calculations may be checked by clicking "Calc". Calibration of Temperature Measurement Channel Since the calibration procedure of the thermistor in the channel have been carried out by the manufacturer, you only need to select the thermistor type and nominal: Click the button «Calibrate». The program will ask for the confirmation: Double-check parameters and click OK. Then select the calibration mode. Page 14 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Automatic mode should be chosen. In the automatic mode, the controller will set the parameters corresponding to your thermistor ; If necessary, the current settings of the thermistor can be checked and the accuracy of measurements can be assessed. This procedure is described in the section «Viewing Current Settings of Thermistor. Checking Measurements.» DX5100 Vision. User Guide. Using the fields for resistance or temperature inputs in «Check function of approximation» (upper boxes on a screenshot below), you can check the agreement of the calculated and experimental values. See the section «Verification of the function of temperature calculation.» DX5100 Vision. User Guide. The block «Measurement of the resistance of the thermistor» allows verification of correct functioning of the temperature measurement channel just by clicking “Measurement”. Version 1.01 2014 Page 15 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. Setting Alarm Limits Setting Limits of TEC Voltage Select correspondent option in DX5100 VISON menu Important! To prevent a thermoelectric cooler (TEC) failure, it is necessary to set correct limit values of TEC voltage. Refer to the TEC specifications . Setting Temperature Limit Values Select correspondent option in DX5100 VISON menu Page 16 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start The tab "Limiting temperatures" allows to specify the maximum and minimum temperatures. If temperature is beyond these limits within the time specified, a corresponding alarm is on and channel will be switched off. The meaning of the parameters to be set is explained by the following picture. Version 1.01 2014 Page 17 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. PID Tuning Select “PID tuning” in “Operation” menu of DX5100 VISION. To fine-tune the PID controller there is a tab: Here you can set the PID controller coefficients andplot the setpoint attaining curve at different values of the coefficients. Finding of optimum parameters of regulation of the given object is quite a delicate and relatively long procedure. It is a consecutive experimental tuning of parameters. Details may be found in DX5100 Technical Manual. Attention! Factory PID settings are just the most common values. Use of the controller without initial PID check and tune with controller TEC and object may result in non-proper temperature control and system failure. To simplify the PID controller optimum parameters choice, in the ТЕС Controller DX5100 the function auto-PID is realized. We recommend to use auto-PID function for setting PID parameters for the first time. This function realizes the known Ziegler-Nichols algorithm. To run auto-PID, select PID setpoint temperature in menu. Setpoint temperature should be the same as nominal stabilization temperature of your object. Then click on “AUTO-PID” in the PID Setting menu. When the process is finished, all coefficients will be displayed in correspondent bars and transient process will be plotted. If you are not satisfied by transient process or other issues you can tune PID coefficients further by yourself. The chapter “PID tuning tips” below describes how different constants affect transients and overall quality of temperature stabilization. Note the “tips” describe the procedure since the very beginning. We recommend to play around values obtained by using “auto-PID” procedure, using “start” and “stop” to check the result of the change. Attention! Maximum TEC voltage must be set BEFORE starting auto-PID Attention! Note The manufacturer does not confirm that the parameters obtained using built-in auto-PID function are the most optimum PID parameters. It is recommended to check up the obtained parameters and if necessary to carry out a more accurate tuning of the PID parameters depending on the required quality of the thermal regulation. PID Tuning Tips The tuning quality can be estimated by different criteria: by the rate of achieving the setpoint, by the minimal overshot, by accuracy of setpoint maintenance. The tuning quality can also be estimation by the transient process of achieving the setpoint. Recommendations for PID tuning by the form of the starting curve are given below. 1. Set values of integrated and differential components equal to zero: Ki=0; Kd=0 Modify the value of the proportional component factor so that the form of the transient process corresponds to that of curve 2 or 3 (see the figure below). Page 18 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start 2. Modify the value of the differential component factor so that the form of the transient process corresponds to that of curve 2. Ttarget T0 3. The integrated component is intended to remove a residual mismatch between the temperature value achieved in the system and the setpoint. Modify the value of the proportional component factor so that the form of the transient process correspond to that of curve 3 (one well-defined relaxion spike with minimum possible oversoot). Ttarget T0 The figure below shows results of manual changing of PID coefficients on controller performance. Version 1.01 2014 Page 19 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. Routine Operation Once ALL setting procedures are completed, DX5100 is ready for routine operation. As mentioned above, there are following operation modes of DX5100 Regulation is off (idle) Mode "Program" T-regulation (relay) Constant voltage maintenance PID regulation Operation modes are briefly described below. Autostart Controller allows you to use it in the stand-alone mode (without a computer). Factory setting is “idle”, but Controller may switches to “Autostart” operation when operation mode is changed from “Idle”. Object temperature is controlled automatically upon applying of 12 V DC power to DX5100 interior. The mode required should be selected by using “Boot Mode” tab in DX5100 VISION. Page 20 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Controlling of indication and regulation. The main parameters will be displayed on DX5100 display; you can select parameters you wish to monitor (set and actual temperature in both channels, TEC voltage and current, etc) by using control buttons, as it is shown on the figure below R Rt L L R 0 mode=OFF 1 R Rt N L R Rt N L mode=PRG R L L Pr=Pr-1 Pr=Pr+1 mode=OFF Rt R 0 mode=OFF 1 L – left button, single click; R- right button, single click; Rt – right button,hold; Rt N L R N Rt N – no clicks of any button in 5 seconds. mode=PRG Pr=Pr-1 Pr=Pr+1 mode=OFF Schematic illustration of changing parameters indicating by DX5100 display. Mode "Program" The Controller has a function "Program" - changing of operation mode in time. This function is carried out by the programs stored in the non-volatile memory. For modifying programs of temperature changing in time there is a tab «Program manager». T-Regulation (Relay) Immediately after starting this mode, for the fastest possible achievement of the temperature setpoint, the TEC maximum allowable voltage is supplied. Heating or cooling mode is chosen depending on the sign of the mismatch of a current temperature and the setpoint. After reaching the setpoint the TEC is exposed to the stepped voltage equal to the specified value UTreg (can be set by command 26). Depending on the mismatch (the difference between the setpoint and actual temperature) and on the sign of the voltage, either UTreg is supplied or 0 volts. The described process is explained by the figure below. Version 1.01 2014 Page 21 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. T[K] 296 294 292 290 288 286 284 282 Tneed=280K U[V] UTECmax=8V UTreg=2V 0 Constant Voltage In the mode the TEC constant voltage is maintained in the appropriate polarity. A User should set a value of constant voltage allowing for a sign. The sign «-» stands for the heating polarity. PID regulation (Constant Temperature) The given mode provides maintenance of constant temperature of an object (TEC). Maintenance of temperature is carried out by TEC voltage calculated according to PID regulation. In this mode the voltage value and polarity are controlled. The temperature is controlled within the allowed limits. The size of the voltage is controlled and does not exceed the limiting value. The PID coefficients are set by the User. Page 22 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Monitoring The VISION program has the mode of monitoring the controller. The monitor allows you to monitor a change in time of up to two parameters simultaneously, as well as a current operating mode. In addition, you can run and stop any regulation mode. Choice of parameter of plot 1 Regulation start and stop buttons Monitoring start and stop buttons Current value of parameter of plot 1 Current value parameter of plot 2 of Choice of parameter of plot 2 Modes Version 1.01 2014 Page 23 / 25 Controller DX5100 Table Top. Quick Start RMT Ltd. TEC Control: DC versus PWM Thermoelectric Temperature Controllers (for managing thermoelectric coolers) are usually based on the PID or PI (proportional–integral–derivative or proportional–integral) regulation mechanism, which is a control loop feedback generally used in industrial control systems. A PID/PI controller calculates an "error" value as the difference between a measured process variable and a desired setpoint. The controlling signals can be various: DC, AC, PWM. A thermoelectric cooler (TEC) is a DC device. Therefore, when there is a TEC application, AC is evidently excluded. However TEC supply with the help of pulse-width modulation (PWM) has become very popular nowadays, as this method is relatively cheaper. Here variable supply may be applied by the time proportioning form - a period time T and signal amplitude Im are fixed, and variation is achieved by varying the duty cycle E.g., a TEC is supplied by the average current I0. Im I0 t T PWM electric current vs time. I0 – average current, duty cycle is /T The regulation is achieved as: I 0=f(/T), where T=const. It works well for instance for resistive heaters, LEDs and others. However, we should always bear in mind that an alternating current of any nature can be detrimental to TEC efficiency (temperature difference). It can be easily understood, if we present the input value (electric current or voltage) in PWM as a superposition of the average and variable values. The average value results in the thermoelectric cooling, whereas the variable one produces the Joule heating only. Pulse-width modulation is compared to DC supply for an example of single-stage 30-pair thermoelectric cooler. TEC 1MC06-030-05 Thot=300 K, vacuum 16 70 Pdc Ppwm(Im=2A) Ppwm(Im=3A) Ppwm(Im=4A) 14 60 12 50 40 Power, W Temperature difference, K 80 DTdc DTpwm(Im=2A) DTpwm(Im=3A) DTpwm(Im=4A) 30 20 10 8 6 4 2 10 0 0 0 1 2 3 4 Electric current, A a) Temperature dirrefernce vs DC or PWM average currents 0 10 20 30 40 50 60 70 Temperature difference, K b) Power consumption to reach temperature difference by DC or PWM average currents Comparison use of DC and PWM supply to TEC operation. TEC type 1MC06-030-05: PWM with different amplitude currents Im=2, 3, 4 A, duty cycle grows 0…1. The example illustrates degradation of TEC efficiency if using PWM instead of DC supply. The use of PWM always gives lower cooling performance of TEC and means always considerable higher power consumption in comparison with the use of DC supply. Page 24 / 25 Version 1.01 2014 RMT Ltd. Controller DX5100 - Table Top. Quick Start Supply method applicable for TECs without interfering with its operation efficiency is DC. It is true for all the problems involving TEC operation, as well as TEC control. Important! The DX5100 Table Top device series is based on DC current for all operational modes. Version 1.01 2014 Page 25 / 25