RMT Ltd. Thermoelectric Module Controller DX5100-Frame Quick Start User Guide RMT Ltd. Moscow, 2013 Version 1.01 DX5100-FRAME. Quick Start RMT Ltd. Table of Contents Features and benefits ........................................................................................................................................ 3 Specifications ..................................................................................................................................................... 3 Common......................................................................................................................................................... 3 Performance................................................................................................................................................... 3 Options ........................................................................................................................................................... 4 Dimensions .................................................................................................................................................... 5 Thermal mounting considerations ..................................................................................................................... 6 How to Get Connected ...................................................................................................................................... 6 Connection terminals in case of one channel ................................................................................................ 6 Connection terminals in case of two channels ............................................................................................... 6 Connector descriptions .................................................................................................................................. 6 TEC Connection ............................................................................................................................................. 7 Thermistor Connection ................................................................................................................................... 7 Power Connection .......................................................................................................................................... 8 DX5100 Vision ................................................................................................................................................... 8 Thermistor Settings ............................................................................................................................................ 9 Procedure Description ................................................................................................................................... 9 Thermistor Current Settings ........................................................................................................................... 9 Choice of Thermistor Type ........................................................................................................................... 11 Temperature as Function of Resistance: ..................................................................................................... 11 Calibration of Temperature Measurement Channel ..................................................................................... 12 Setting Alarm Limits ......................................................................................................................................... 14 Setting Limits of TEC Voltage ...................................................................................................................... 14 Setting Temperature Limit Values ................................................................................................................ 14 PID Tuning ....................................................................................................................................................... 16 PID Tuning Tips ........................................................................................................................................... 16 Operation Modes ............................................................................................................................................. 18 Autostart ....................................................................................................................................................... 18 Mode "Program" ........................................................................................................................................... 18 T-Regulation (Relay) .................................................................................................................................... 18 PID regulation (Constant Temperature) ....................................................................................................... 18 Constant Voltage.......................................................................................................................................... 19 Monitoring ........................................................................................................................................................ 19 TEC Control: DC versus PWM ........................................................................................................................ 20 Page 2 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. 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 by one Controlling Board - Power channels of two versions: high-power 4Aх8V and low-power 3Aх5V - TEC operation current and voltage range as ±4A and ±8V per channel. - PID temperature regulation mode - Constant voltage operation mode - T-Regulation (relay) mode - Mode of temperature programming in time - DC current 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 RS232 and RS485 - Network of up to 32 Channels is available jointed by RS485 bus - Software for RS232 and RS485 protocols - 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 Remote control 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 BIN & SYM Combined by RS485 Every Channel Performance Name Maximal current Maximal voltage Maximal power Maximal current Ver. 1.01 2013 Units Value Maximal Parameters (Options: Frame 1…4) A 4 V 8 W 32 Maximal Parameters (Options: Frame 5, 6) A 3 Comments Per channel Per channel Page 3 / 20 DX5100-FRAME. Quick Start RMT Ltd. Name Units Maximal voltage Maximal power Regulation channels number Value 5 15 2 Parameters of TEC Voltage Regulation Voltage Range V -8…+8 Voltage Range V -5…+5 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 temperature Yes programming in time Programs cascading Yes Comments V W Digital Board Options: Frame 1…4 Options: Frame 5, 6 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% Options The controllers DX5100 Frame are available in six equipment options Device Option Frame 1 Frame 2 Frame 3 Frame 4 Frame 5 Frame 6 Channel parameters 8V x 4A 8V x 4A 8V x 4A 8V x 4A 5V x 3A 5V x 3A Number of channels 1 1 2 2 2 2 Display module + + + Frame type Low profile Normal profile Normal profile Normal profile Low profile Normal profile Overall dimensions, mm 126x114x21 126x114x28 126x114x28 126x114x28 126x114x21 126x114x28 Weight, g Important! The DX5100-Frame controller series is based on DC current regulation by TEC for all operational modes (See chapter “TEC Control: DC versus PWM”). Page 4 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start Dimensions Normal profile housing 2 1 6 Frame 2 Frame 3 Frame 4 Frame 6 7 4 5 3 Recommended Airflow Direction Low profile housing 2 1 Frame 1 Frame 5 4 5 3 1 2 3 4 5 6 7 Ver. 1.01 2013 Housing base Cover Connecting terminals Power switch Connector miniUSB Indicator (LCD Display) (only Frame 2, 4, 6) Control buttons (only Frame 2, 4, 6) Page 5 / 20 DX5100-FRAME. Quick Start RMT Ltd. Thermal mounting considerations The DX5100-FRAME controllers are rated to dissipate a significant amount of heat, and must be adequately heat sinking in order to prevent overheating the controller. An external heat sink is necessary, and at higher power dissipation a fan will be required to increase airflow over the heat sink. Important! Ensure adequate heat sinking and airflow are provided in order to prevent overheating. How to Get Connected There are connection terminals on one side of the controller. There are two terminal versions, depending on the number of channels. Connection terminals in case of one channel RS485 A TEC1 B GND 1 2 3 Rt1 F 4 5 6 7 8 9 S OUT1 S INPUT 1 F 10 11 12 13 14 15 12VDC E 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Connection terminals in case of two channels RS485 A B GND 1 2 3 TEC2 Rt2 F S TEC1 S F 4 5 6 7 8 9 Rt1 F S OUT2 S F 10 11 12 13 14 15 OUT1 2 INPUT E 1 12VDC E 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Connector descriptions Contact # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Page 6 / 20 Circuit Signal A of interface RS485 Signal B of interface RS485 Signal GND of interface RS485 TEC+ TECF+(force) connections to thermistor. S+(Kelvin sense) connections to thermistor. S- (Kelvin sense) connections to thermistor. F- (force) connections to thermistor. TEC1+ TEC1F+(force) connections to thermistor. S+(Kelvin sense) connections to thermistor. S- (Kelvin sense) connections to thermistor. F- (force) connections to thermistor. Normally closed contact of the relay Chanel Common relay Chanel Normally open contact of the relay Chanel Normally closed contact of the relay Chanel Common relay Chanel Normally open contact of the relay Chanel Control of channel (digital input) Common of digital input Enables to control (digital input) Control of channel (digital input) Common of digital input Notes RS485 Channel 2 Channel 1 Channel 2 Channel 1 Channel 2 Channel 1 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start Contact # 27 28 29 Circuit Enables to control (digital input) Power + Power - Notes Power Supply TEC Connection Important! For the proper functioning of a controlled TEC we should ensure an effective heat rejection from the hot side of the TEC. This is achieved by a heat sink (possibly with forced cooling) with a good thermal contact of the TEC hot base and the heat sink surface. Important! The TEC should be connected according to the correct polarity. When applying to the TEC voltage polarity corresponding to the circuit name, the TEC operates in the cooling mode. Thermistor Connection Important! There should be a thermal contact of the sensor with the controlled TEC. The location of the thermistor must be as close to the TEC cooled surface as possible, to minimize transportation lag. Transportation lag is the time from the moment the voltage changes to the moment the feedback is received. The feedback is the temperature change caused by this change in voltage. . The thermistor can be connected by a 4-wire or 2-wire circuit. 2-wire connection is recommended for the sensor resistance more than 1 Ohm. For this connection, appropriate connecting terminals contacts should be bridged. For channel 1 connect in pairs contacts 1213 and 14-15. For channel 2 connect in pairs contacts 6-7 and 8-9. We recommend connecting the thermistor by a twisted pair or by two twisted pairs for 4-wire circuit. The wires of the sensor and current circuits are twisted in pairs. TEC Rt F S TEC S F 4 5 6 7 8 9 10 11 12 13 14 15 Rt F Channel 2 Channel 1 4-wire connection of thermistor S S F 4 5 6 7 8 9 10 11 12 13 14 15 Channel 2 Channel 1 2-wire connection of thermistor Connection of TEC and thermistor to the controller Ver. 1.01 2013 Page 7 / 20 DX5100-FRAME. Quick Start RMT Ltd. Power Connection Connect the power supply, with polarity in mind. The power supply source should provide voltage 12±10% V. Important! Power supply must be chosen based on the number and the total 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. DX5100 Vision Install the DX5100 Vision program supplied or downloaded from http://rmtltd.ru/downloads/. the manufacturer's website Connect the controller to a computer via the cable miniUSB. By default, the controller has a rate setting of 19200 kbps. 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 8 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. 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 The thermistor setting means finding and storing parameters of the ADC channels for each thermistor in the non-volatile memory. Thermistor Current Settings 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 ( ), 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: Ver. 1.01 2013 Page 9 / 20 DX5100-FRAME. 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 10 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start Choice of Thermistor Type To simplify the setup procedure, the program offers a choice of predefined characteristics of thermistors. The list includes the 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, you can use the point "User defined". 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: Steinhart-Hart equation: ( ) ( ) When you select the Steinhart-Hart equation, you will be asked to enter 3 points of the dependence of temperature on resistance. This information is usually provided by a thermistor manufacturer. The extreme points should be at the edges of the working range, while the average - in the middle. 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 have to enter the coefficients. You may check the results of calculations of the function of calculating temperature by pressing "Calc". 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. Ver. 1.01 2013 Page 11 / 20 DX5100-FRAME. Quick Start RMT Ltd. Calibration of Temperature Measurement Channel Since the calibration procedure of the measurement 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: You will be asked to select the mode: The mode Automatic should be chosen. In the automatic mode, the controller will set the parameters corresponding to your thermistor ; Page 12 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start 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 the block «Check function of approximation», 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 assessing the functioning of the temperature measurement channel. Click «Measurement», as a result we get current values of the sensor resistance and temperature. Ver. 1.01 2013 Page 13 / 20 DX5100-FRAME. Quick Start RMT Ltd. Setting Alarm Limits Setting Limits of TEC Voltage 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 The tab "Limiting temperatures" allows you to specify the maximum and minimum temperatures. If temperature is beyond these limits within the time specified, a corresponding alarm is on and PID control is off, the alarm conditions. Page 14 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start The meaning of the parameters to be set is explained by the following picture. Ver. 1.01 2013 Page 15 / 20 DX5100-FRAME. Quick Start RMT Ltd. PID Tuning To fine-tune the PID controller there is a tab: Here you can set the PID controller coefficients, plot the setpoint attaining curve at different values of the coefficients. The controller has a built-in function "AUTO-PID". When using it, you may get the initial values of the coefficients. The finding of optimum parameters of regulation of the given object is quite a delicate and long procedure. It is a consecutive experimental tuning of parameters. At the same time the quality of temperature regulation and problems solutions depends on the optimality of the set parameters. Attention! The parameters preset at the device delivery are formal and do not concern a real controlled object. To simplify the PID controller optimum parameters choice, in the ТЕС Controller DX5100 the function autoPID is realized. This function realizes the known Ziegler-Nichols algorithm. The user applying this function can use the obtained PID controller parameters for the subsequent accurate adjustment or apply the given parameters directly to the control of the object. Attention! Before starting the auto-PID function it is necessary to set thermoelectric module maximal allowable voltage . Attention! Nevertheless the manufacturer regards the parameters obtained with the help of the built-in auto-PID function as estimated and not quite optimum. 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 transitive characteristic correspond that of curve 2 or 3 (see the figure below). Page 16 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start Kp1>Kp2>Kp3>Kp4>Kp5 Ttarget T0 2. Modify the value of the differential component factor so that the form of the transitive characteristic correspond 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 transitive characteristic correspond to that of curve 3. Ttarget T0 Ver. 1.01 2013 Page 17 / 20 DX5100-FRAME. Quick Start RMT Ltd. Operation Modes There are several modes of regulation: Regulation is off Mode "Program" T-regulation (relay) PID regulation Constant voltage maintenance Autostart Any of the possible modes can be started automatically after the controller switching on - autostart. This allows you to use the controller in the stand-alone mode (without a computer). There is a tab «Boot Mode» for choosing the autostart mode and setting the parameters. References provide background information on possible operating modes. 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. T[K] 296 294 292 290 288 286 284 282 Tneed=280K U[V] UTECmax=8V UTreg=2V 0 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. Page 18 / 20 Ver. 1.01 2013 RMT Ltd. DX5100-FRAME. Quick Start 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. 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. Monitoring The 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 Ver. 1.01 2013 Page 19 / 20 DX5100-FRAME. 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: I0=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 Ohmic 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 to use PWM instead of natural 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. 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-Frame device series is based on DC current for all operational modes. Page 20 / 20 Ver. 1.01 2013