Ramsey-electronics COMPUTEMP CT255 Uživatelský manuál Strana 1

CT255 • 1 COMPUTEMP 255 BINARY THERMOMETER KIT Ramsey Electronics Model No. CT255 A really neat educational kit to learn the principles of

CT255 • 10 At 100.0 degrees Fahrenheit the temperature sensor will have an output of a value related to Celsius, so to make life easier, we will conv

CT255 • 11 128 times to get the most significant LED to change state just once. Normally an 8 bit number has these significant values: Say bits 7, 3,

CT255 • 12 You may notice though that the smallest step in this case is 1/256. This 8 bit DSP is unable to accurately represent this number smaller t

CT255 • 13 CT255 SCHEMATIC DIAGRAM

CT255 • 14 CT255 PARTS LAYOUT DIAGRAM

CT255 • 15 PARTS SUPPLIED WITH YOUR CT255 KIT Capacitors  4 .1 µF disc capacitor (marked .1 or 104 or 100 nF) [C3,4,5,6]  1 1 µF electrolyt

CT255 • 16 RAMSEY "LEARN-AS-YOU-BUILD KIT ASSEMBLY There are numerous solder connections on the CT255 printed circuit board. Therefore, PLEASE

CT255 • 17 CT255 THERMOMETER ASSEMBLY INSTRUCTIONS Although we know that you are anxious to complete the assembly of your binary thermometer kit, i

CT255 • 18 installed). Since a diode will only conduct when it is forward biased, this diode acts as a “reverse voltage” protection circuit. Diodes a

CT255 • 19 Next we will install some of the output voltage divider resistor networks. The circuit board has been laid out to avoid confusion with th

CT255 • 2 RAMSEY TRANSMITTER KITS • FM100B Professional FM Stereo Transmitter • FM25B Synthesized Stereo FM Transmitter •

CT255 • 20  16. Install C2, 10 uF electrolytic capacitor. Remember to observe polarity with electrolytic capacitors! Check the parts placement diagr

CT255 • 21 install all eight so that they are in line. A trick may be to fashion a cardboard “standoff “ and pre-bend the LEDs before installing  35

CT255 • 22  40. FOR REMOTE SENSOR OPERATION. If you wish to run the sensor to a remote location, you will need to obtain a 3.5 mm stereo plug and w

CT255 • 23 CONGRATULATIONS ! Your binary thermometer is now complete! Have a final look over your work, paying particular attention to the orientat

CT255 • 24 USE OF YOUR COMPUTEMP 255 Now we are ready for the moment of truth, the initial power up and running of your binary thermometer. Energize

CT255 • 25 TROUBLESHOOTING GUIDE If your CT255 does not work at all, recheck the following: • correct orientation of VR1, U1, and U2 (see PC board la

CT255 • 26 If all else fails, call or email Ramsey Tech Support at 585-924-4560 or [email protected]. We’ll try to help talk you through th

CT255 • 27 The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting

CT255 • 28 RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 Fax (585) 924-4555 www.ramseyelectronics.co

CT255 • 3 COMPUTEMP 255 BINARY THERMOMETER KIT Ramsey Publication No. MCT255 Price $5.00 TABLE OF CONTENTS Introduction ...

CT255 • 4 INTRODUCTION Years ago Ramsey Electronics had a really neat little kit called the CompuTemp 127. This was a favorite kit purchased by many

CT255 • 5 CIRCUIT DESCRIPTION There’s a lot of circuitry in the CT255 that is in use to this day in a variety of circuits. We will begin with the tem

CT255 • 6 The DAC (Digital to Analog Converter) The resistor values in this ladder are chosen to give us nice even steps in the voltage range we are

CT255 • 7 in series with the input to reduce any noise that may be present on the temperature sensor to increase accuracy of your reading. C3 in the

CT255 • 8 How the counter oscillator works U1:D is set up as a simple oscillator to generate our clock pulses that drive the ripple counter. When the

CT255 • 9 to add 32. We do this by switching in R22 into the circuit, which combined with R23 adds in the 32 offset that we need. The problem however