TCII micro-temperature Controller INSTRUCTION MANUAL

Transcription

1 TCII micro-temperature Controller INSTRUCTION MANUAL July 2004 Copyright by N.B. Datyner, 2004 All rights reserved., PO Box 11387, Norfolk, VA Phone: (800) Fax: (800) WWW: 1

2 TABLE OF CONTENTS PAGE CAUTIONS... 3 INTRODUCTION... 3 CONTROLS & DISPLAY Front Panel ON... 3 Ch1, Ch2 LEDs... 3 LCD display... 3 Up/Down... 4 Menu... 4 <CR>... 4 Edge DC In... 4 Ch1, Ch2 Probe/Heat... 4 RS OPERATION Connections and basic operation... 5 Thermistor placement... 5 Special features... 5 RS Downloading updated firmware... 6 ACCESSORIES... 6 SPECIFICATIONS... 7 APPENDIX Heater/thermistor jack

3 CAUTIONS The TCII has been designed to withstand normal laboratory use. However there are still some precautions that you must take or you will either damage the unit or shorten its life. Limit the power supply voltage to 15VDC. If you reverse the supply the TCII is protected. You may damage the unit with higher voltage supplies. Make sure the vent on the rear and top edge are not obstructed to allow air flow over the internal electronics. Of course don't spill fluids on the unit. The front panel can be cleaned with rubbing alcohol. Don't expose the TCII to temperature extremes (<10C or >35C). INTRODUCTION The TCII -Temperature Controller II is a multipurpose two channel microcomputer based temperature controller, small enough to be fit into any lab situation yet flexible in its design and able to deliver significant heating current. The TCII uses a state-of-the-art microcontrollers to provide an instrument where the firmware can be easily updated via the serial port. This ability allows customization of the firmware for special applications as well as computer control. The TCII uses proportional and integral control to provide accurate temperature regulation. It can control currents up to 1.5Amps in each channel. Front Panel CONTROLS & DISPLAY ON When the ON LED is lit when power is being provided from the DC In jack. Ch1, Ch2 LED's These LEDs usually indicate the power being applied to the heater but they can also flash with error conditions such as high temperature readings. You will notice that even when the LED's are dimly lit there is a brief bright pulse. This happens because on each control cycle the unit tests the heater to make sure that it is not shorted or open circuit. A brief pulse is applied to the heater and the current measured to verify that it is within a normal range. If the heater is shorted the display will briefly show HChk. Power is shut off to the heater. They will also flash briefly if the thermistor temperature is too high (>65 o C). LCD display At power up the top line of the display shows Ch1 probe temperature. The second line shows the Ch2 probe temperature. The top line shows "open" when the thermistor is not plugged in. Provided the heater has sufficient power to heat and the thermistor is suitably positioned the thermistor temperature will increase to approach the setpoint. The thermistor temperature can remain below the setpoint because of insufficient power being put out by the heater or because of limited gain in the control algorithm. The temperature can also overshoot past the setpoint and then settle back to the setpoint. Up/Down These two keys move the setpoint up or down by 0.1 o C increments. Press the up arrow and the display shows 3

4 the Ch1 (top line) and Ch2 (bottom line) setpoints. Press the up arrow to modify the Ch1 setpoint or down arrow for Ch2 setpoint. When the setpoint is set to what you want press <CR>. If the heaters are on then when you finish changing the setpoint the unit will start controlling the temperature using the new setpoint. Menu Pressing this key allows the control and other parameters to be changed. DM-display mode 0-Upper-Ch1 temp, lower Ch2 temp 1-Upper-upper Ch1 temp 2-Upper-lower Ch2 temp P1-Digital control [Ch1]-proportional gain-typical 50 I1-Digital control [Ch1]-integral gain-typical 35 B1-Digital control [Ch1]-band limit-typical 100 P2-Digital control [Ch2]-proportional gain-typical 50 I2-Digital control [Ch2]-integral gain-typical 35 B2-Digital control [Ch2]-band limit-typical 100 FD-Diagnostic flags 0-diagnostics off 1-Ch 1, Ch2 temp via serial port only when heater on 5-Ch 1, Ch2 temp via serial port 6-Diagnostics via serial port Open loop test 10=20%;11=40%;12=60%;13=80%;14=100% power Also outputs Ch1, Ch2 temp Ts-Interval for serial output-higher number=>lower output rate ON CH1 CH2 CH2 [HT1/2] CH1 [PB1/2] TC 2Ch Temperature Controller RS232 DC In Edge DC In Power used for heating. Limit the input voltage to 15VDC. Higher voltages may damage the output power circuitry. Voltages of <15V (must be >10V) can be used but the output power will be less. Ch1/[HT1/2] The TCII comes set up for two heater/thermistor assemblies. It can be set up (using internal jumpers) so that Ch1 is used for both heaters and Ch2 for both probes. An adapter cable is supplied for each channel to allow separate probes and heaters to be used. If you want to connect your own heater and thermistor (10kohm type) use the diagram in the Appendix for the connections. Heaters should have a resistance between 5 and 15Ω. Do not exceed heater currents of 1.5Amps or you may blow the internal fuse and possibly damage the output power circuitry. The TCII tests the heater resistance every 200ms and will shut off the output if the resistance of the heater is too low or if the heater resistance is too high (eg. open circuit). In this case the display will briefly show "HChk" and shut off the channel. If the probe is disconnected or broken it will show "open" on the display. Ch2/[PB1/2] See Ch1. This channel can be set up for two probes. RS232 The unit is supplied with a cable with a serial DB9 connector to plug into a PC serial port. If your PC doesn't have a serial port you can use a USB to serial converter. The serial port is used to download updated firmware, receive data from the TCII and control various functions of the TCII. 4

5 OPERATION Connections and basic operation Use the adapter cable provided if you have a separate heater and temperature sensor or plug in a heater assembly (eg. HC-1P, HF-2P, HF-3P). Connect the power supply that came with the TCII to the DC In on the edge of the unit. Do not use any other power supplies without consulting us. The 15V 4Amp supply provides sufficient power for use of both channel simultaneously. The TCII should will indicate the thermistor temperature for Ch1 on the top line and Ch2 on the second line. The display can be modified by altering the DM parameter in the Menu. If a thermistor is not plugged in the temperature the display will show "open". If you have two channels in use the heaters can be started similtaneously by pressing <CR> twice. You will see the display show "On?". If you press the up arrow you can select only channel 1. If you press the down arrow you can select channel 2. Pressing <CR> again selects both channels. Similarly when you want to turn off both or an individual channel. If only one channel is on the pressing <CR> twice turns off the channel that is on. Thermistor placement The thermistor probe has to be sensibly placed so that it reads the temperature of the sample etc. that you want to maintain at a specific temperature. The probe needs to be in intimate contact with a surface. Air is a good insulator so small air spaces around the probe will prevent it from accurately measuring a temperature. If possible use epoxy (or silicon glue) to glue the probe to a surface with a representative temperature. For example if you are keeping a sample warm inside a Thermos or Dewar place the heater (eg. using the HF-1P) around the perimeter of the inside and the thermistor probe adjacent to the sample. Place a spacer between the heater and the sample with thermistor probe attached. If however you placed the thermistor adjacent to the heater this will slow down heating of the Dewar since the heater will quickly warm to the setpoint temperature. In this example because the Dewar is a good insulator there will be only small temperature gradients within the Dewar so eventually everywhere within the Dewar inside will be at the setpoint temperature. Consider another example. Suppose you have a test tube surrounded by a foil heater (eg. HF-2P). Ideally you would like to place the thermistor inside the fluid in the test tube but since the thermistor is not waterproof the next best thing would be to place the probe inside a sealed glass tube that is then immersed in the test tube fluid. Placing the thermistor on the outside of the foil heater will not provide a representative measure of the fluid temperature. If you are using the TCII to control the temperature of a small animal (eg. mouse) then you can use the TH-10kmr as a rectal probe. Keep in mind that there is only "loose" thermal coupling (via the animal circulation and contact with the heater) between the rectal probe and the heater so it will take time for the heater to influence the animals temperature. You also may need to limit the maximum output power using the B "Band Limit" parameter. For the HS-105 heater the parameters P=50, I=35, B=100 are satisfactory. For the HS-3x2.5 P=50, I=30, B=60 are satisfactory. Please call us for parameters for other heaters or experimental situations. We will also post additional application information on our website. Special features The firmware has several valuable features to protect the TCII electronics from damage. If the heater is shorted or the output accidentally shorted the TCII will shut down the power to that channel within 0.3sec and briefly show "HChk" on the LCD display. The message will only show briefly and only when you turn on the channel. The TCII has an intermal heatsink for the power amplifiers. The temperature of the heatsink is sensed by the microcontoller and a small internal fan turned on if the temperature exceeds a threshold. The fan will stay on until the heatsink temperature drops below a lower threshold. If the fan is unable to maintain a satisfactory temperature for the heatsink the outputs are shut down and the display will show "HS Hot" until the heatsink has cooled down. The fan will typically come on when two channels are being operated in digital mode. The TCII also has a versatile RS232 port for both control and data output. This is described below. RS232 port The RS232 port is used to download updated firmware as well as receive diagnostic and temperature data. It can also be used to change the setpoints and turn the heaters on and off. You can use a Terminal emulator such as Hyperterminal that comes with Windows. Set the parameters to 9600 baud, 8 bits, no parity, one stop bit and 5

6 connect the supplied cable to the chosen serial port. If you don't have a serial port use a USB to serial converter. "H"-turn on Ch1 "h"-turn off Ch1 "I"-turn on Ch2 "i"-turn off Ch2 "S"-turn on brief diagnostics-setpoints and temperatures "s"-turn off brief diagnostics "D"-turn on long diagnositcs, as for "S" plus fan temp, output levels, error signals etc "d"-turn off long diagnostics "#nttt"-n=0(ch1) or 1(CCh2), TTT is new setpoint eg. change setpoint for Ch1 to 37.2 would be #0372 TCII acknowledges command by transmitting a "#' character. Downloading update firmware You should download the bootloader from and install it on your PC. To download new firmware locate the new firmware file (eg. mtc24a.hex). Make sure the TCII is unplugged and click on Write (F4) in the PIC downloader screen. Then plug in the power to the TCII and you will see the progress bar move across. Once the new firmware is downloaded the TCII restarts with the new firmware. Accessories There are several heater/thermistor assemblies for the TCII, the HC-1P, HF-2P, HF-3P, HS-105P and HLS-1P. It can also be used with our silicon heaters and TH-10Km or TH-10Kmr probes. In this case you use the supplied adapter cable. Some applications for the heater assemblies are given below: HC-1P Heater assembly - concentric foil Application The HC-1P can be easily attached to an aluminium plate with a central hole for viewing and used for heating 30mm culture dishes. This can form a simple heated stage for a microscope. 1cm size 40mm outer dia. x 24mm central hole dia. resistance nominally 6.4Ω constructed of a thin foil coated with Kapton insulation. Total thickness 0.35mm. One side coated with pressure sensitive adhesive. max. operating temperature 100 C HF-2P Heater assembly - square foil 5cm Application The HF-2P can be used for heating plates, small tubes etc. To attach it to plates you can use 3M Hi Temperature Acrylic adhesive. This is a double sided adhesive. To heat a tube you should wrap the heater around the tube and use either rubber bands or heatshrink bands to hold the heater against the tube. The thermistor probe should be located so that it measures the temperature in the tube (see Thermistor placement). size 50mm x 50mm. resistance nominally 5.3Ω constructed of a thin foil coated with Kapton insulation. Total thickness 0.3mm. max. operating temperature 150 C 1cm HF-3P Heater assembly - square foil 8cm Application The HF-3P can be used for heating plates, tubes etc. It is also suitable for heating laboratory Dewars (eg. 0.5L Dewar Cat# H , Stopper H Cole Parmer, ). The heater is spread around the inner surface and samples placed in the central area. The thermistor probe should be placed next to the 6

7 samples with a spacer separating them from the heater. size 80mm x 80mm resistance nominally 4.9Ω constructed of a thin foil coated with Kapton insulation. Total thickness 0.3mm. max. operating temperature 150 C 1cm HS-105P Heater assembly - silicon 25x12cm The HS-105P can be used as a small animal heater or in applications where a large area needs to be heated to 35 o C. For example tissue covered culture dishes can be placed on the heater while they are awaiting microscopic examination. size 25cm x 12cm. resistance nominally 8.5Ω constructed of a thin foil coated silicon. Total thickness 0.5mm. max. operating temperature 150 C 1cm HLS-1P Heater assy-lens, silicon Application: objective heater and thermistor probe. heater size 20x70x 0.35mm thick max. operating temp. 150 o C SPECIFICATIONS Temp Ref Range: 5 C to 45 C. Accuracy: ± 0.2 C Heater Output: 0 to 12V at up to 1.5Amps. PWM (pulse width modulated) output (15W max) Analog (8Wx2 peak, 2Wx2 cts-10ohms ) Suitable Heaters: 5 to 15Ω resistance. Supply Voltage/DCIn: nom. 15V at up to 4Amps. Included power supply: 15V, 4Amp switching power supply. Temperature sensor: 10kohm thermistor Fan: internal fan under microprocessor control Control: RS232 port for temperature logging and control Environmental: Operating temperature 15 o C to 30 o C. Dimensions: 4.5 x 3.25 x 1.5 inches (LxWxH) 7

8 Heater/thermistor jack Appendix The heater/thermistor jack has the contacts shown in the figure. The voltages for the heater are given for reference purposes if for example you wished to ground one of the heater leads. Note that if you ground one of the heater leads you must have an isolated power supply. Typically most block power supplies are isolated from ground Mini DIN4 plug looking face on at plug Mini DIN4 plug looking at rear of plug where wires are soldered 1 & 2 Heater connections (2. is at approx. VDCIn-0.5V 1. is at approx 0.5V) 3 & 4 Thermistor connections 8