User Manual

ADC-20/ADC-24 Terminal Board User Guide Pico Technology
8 DO117-5
2.5 Temperature
2.5.1 Introduction
If you use the ADC-20/ADC-24 Terminal Board and ADC-20 or ADC-24 with a suitable
sensor and the Picolog software, you can measure temperatures accurately. There are
three methods of measuring temperature, each using one of the following sensors:
• LM35DZ integrated circuit sensor
• Precision thermistor
• Thermocouple used with AD595 integrated circuit
Note: If you require several temperature sensors, Pico Technology’s USB TC-08
thermocouple interface is a better product to use, as you can plug up to eight
thermocouples into it simultaneously.
2.5.2 LM35DZ IC
Temperature sensor circuit with LM35 IC
The LM35DZ IC is a combined precision temperature sensor and signal conditioner
supplied in a three-pin TO92-style package. Of the three devices, this is the easiest to
connect to the ADC. The device measures temperatures in the range 0°C to +100°C
and includes the electronics required to convert temperatures to a linear voltage of 10
mV/°C. The diagram below shows how to connect this device to the terminal board.
Fit the LM35 to the terminal board in position Q1. To convert the voltage to a
temperature reading, use PicoLog’s scaling equation facility. Set the scaling equation
to: X * 100. For more information, see PicoLog’s electronic manual (PLW044.PDF in
your Pico Technology installation directory).