Making Measurements 3Keysight U1401B User’s and Service Guide 65Measuring TemperatureThe bead type thermocouple probe is suitable for measuring temperature from–40 °C to 204 °C in PTFE compatible environments. Above this temperature range,probes may emit toxic gas. Do not immerse the thermocouple probe in any liquid.For best results, use a thermocouple probe designed for each specificapplication — an immersion probe for liquid or gel, and an air probe for airmeasurements. Observe the following measurement techniques:– Clean the surface to be measured and make sure that the probe is securelytouching the surface. Remember to disable the applied power.– When measuring above the ambient temperature, move the thermocouplealong the surface until you get the highest temperature reading.– When measuring below the ambient temperature, move the thermocouplealong the surface until you get the lowest temperature reading.– Always set the slide switch to the M position (meter operation only). Place theinstrument in the operating environment for at least one hour as theinstrument is using a non-compensation transfer adapter with miniaturethermal probe. If you are using the type of thermocouple probe where thethermal wires penetrate into the banana or lantern terminals, you only need toplace the instrument in the operating environment for at least 15 minutes.– For quick measurements, use the 0 °C compensation to observe thetemperature variation of the thermocouple sensor. The 0 °C compensationmakes it possible for you to measure the relative temperature immediately.To measure temperature, follow these steps:1 Set the slide switch to the M position to disable the output.2 Turn the rotary switch to the position.3 Press and hold for more than 1 second to select temperature measurement.4 Plug the thermocouple adapter (with the thermocouple probe connected to it)into the positive and negative input terminals (Figure 3-4 on page 66).CAUTION Do not bend the thermocouple leads at sharp angles. Repeated bendingover a period of time may break the leads.
