UNIVERSAL TEMPERATURE SENSOR K8067 rfac uter inte p m o c 47, ..
VELLEMAN NV Legen Heirweg 33 9890 Gavere Belgium Europe www.velleman.be www.velleman-kit.
Features & Specifications Features: Small and compact unit. Wide temperature range. One single adjustment. Excellent noise immunity thanks to current loop system. Easily adaptable for 0..5V or 0..10VDC output. Specifications: Temp. range : -20 to +70°C Output : 20mA current loop Max. voltage : 10V in 500 ohm Accuracy : 2° of full range 3-wire system Power supply : 12VDC for 0..5V OUT 15VDC for 0..10V OUT Current consumption : 30mA max.
Assembly hints 1. Assembly (Skipping this can lead to troubles ! ) Ok, so we have your attention. These hints will help you to make this project successful. Read them carefully. 1.1 Make sure you have the right tools: A good quality soldering iron (25-40W) with a small tip. Wipe it often on a wet sponge or cloth, to keep it clean; then apply solder to the tip, to give it a wet look. This is called ‘thinning’ and will protect the tip, and enables you to make good connections.
Assembly hints 1.3 Soldering Hints : 1- Mount the component against the PCB surface and carefully solder the leads 2- Make sure the solder joints are cone-shaped and shiny 3- Trim excess leads as close as possible to the solder joint AXIAL COMPONENTS ARE TAPED IN THE CORRECT MOUNTING SEQUENCE ! REMOVE THEM FROM THE TAPE ONE AT A TIME ! You will find the colour code for the resistances and the LEDs on our website: http://www.velleman.be/common/service.
Construction 1. Zenerdiode. Watch the polarity ! CATHODE ZD... 3. IC socket, Watch the 6. Voltage reference position of the notch ! VR1 : LM385 - 2.5 !!! IC1 : 14P VR... LM335 ZD1 : 12V0 - 500mW 2. Metal film resistors 4. Capacitors. 7. Multiturn trimmer R... C... R V . ..
Construction 9. Electrolytic Capacitor. Watch the polarity ! C2 : 100µF C ... 10. IC. Watch the position of the notch! IC1 : TLV274 or eq.
Sensor 11. Sensor LM335 The sensor can be placed at a remote location (fig 1.0) instead of on the board (fig 2.0). Max. 1m Fig. 1.0 Fig. 2.
Sensor Remote location : Use shielded cable (3.0) and connect the shielding to the ground (sensor pin marked with an arrow on the PCB, see fig 4.0) Shielded cable Fig 4.0 Fig 3.0 shielding Sensor Max. sensor to board distance : 1m Sensor and PCB must be shielded from moisture at all times. Use shrink tube or resin to protect sensor, fig 5.0. Fig 5.0 Keep in mind that the sensor has a thermal response time of at least 4 minutes in still air.
Sensor On board : Follow the steps displayed in figures 6.0 through 6.2 if you want to mount the sensor directly on the PCB. Solder now the connections of the sensor. GND Solder Fig. 6.0 10 Fig. 6.1 Fig. 6.
Connection 12. Connection to interface card or application: Most applications require 0..5V or 0..10V. Put a resistor between the interface input and ground to convert the current to voltage. To calculate the resistor value, divide the max. desired voltage (e.g. 5V) by 0.02. The result is the required resistor value in ohms. In this example : 5/0.02 = 250 ohm (4 x 1K ohm resistor in parallel). See diagram 7.0. 1K 1K 1K 1K Ex. K8000, K8047, K8055, ... INPUT AD GND - + Fig. 7.
Software 13. Software : Our website ‘www.velleman.be’ features example software written in VB6. Source code is supplied. Use the source code as a guide to write your own applications. The following formula converts the value returned by the AD converter to °C: °C = (101 * AD-value / 256) - 23 '256' is a value used with an 8-bit AD-converter.
Calibration 14. Calibration Connect the sensor to the interface board and apply power to the sensor board. Leave it idle for at least 15 minutes, to allow it to adapt to ambient temperature and put a reliable thermometer next to the sensor. Run your software or the test software. Adjust 'T adj' on the K8067 board until the displayed temperature corresponds with the thermometer indication.
PCB 15. PCB layout.
Diagram 16. Diagram +V R1 10K +V (1) Current loop resistor : For 0 to 10V : 500 ohm (V+ = 15V) For 0 to 5V : 250 ohm (V+ = 12V) VR1 LM385-2.5 6 5 7 IC1B +V 100E R10 R9 R8 GND +V 200K 3 R6 IC1A 1 12 13 200K RV1 10K T.Adjust SENS1 LM335Z 9 2 R5 R2 10K R3 10K GND 200K 10 11GND 14 +V 4 T2 BC557 8 IC1C T1 BC547 IC1D SK1 +V R7 200K R4 10K GND GND C2 100µF/25V C1 100n GND GND 0.
VELLEMAN NV Legen Heirweg 33, B-9890 GAVERE Belgium (Europe) Modifications and typographical errors reserved © Velleman nv. H8067IP’1 - 2014 (rev.