INFICON RQCM - Quartz Crystal Microbalance Research System - Manual (Page 88)

RQCM – RESEARCH QUARTZ CRYSTAL MICROBALANCE
DATA ACQUISITION CARD (OPTIONAL) 8-2
8.2 TEMPERATURE INPUTS
Three temperature inputs are included to support the three most commonly used temperature
sensors: thermistor, Resistance Temperature Detector (RTD), and type T (copper constantan)
thermocouple.
8.2.1 THERMISTOR INPUT
The Thermistor Input is designed to use an Omega 10 KΩ @ 25°C – Precision Interchangeable
Thermistor P/N 44006, or equivalent. Shielded, twisted pair is recommended for the leads.
This thermistor has a range of 0 to 150°C. The use of a thermistor provides high accuracy
measurements within its temperature range, or when long leads are required.
8.2.2 RTD INPUT
The RTD has a range of 0 to 600°C. The use of the RTD is for the measurements in the higher
temperature ranges.
The RTD input is designed to use an RTD conforming to the European standard curve with an
alpha of 0.00385 for the Calendar-van Dusen equation and a resistance of 100 ohms @ 0°C. The
RTD is connected as a four-wire element, using a pair of wires for excitation and pair of wires to
sense the voltage across the element. This configuration should be continued all the way to the
probe for maximum accuracy. A single shielded cable with two twisted pairs, or two shielded,
twisted pair cables should be used.
8.2.3 THERMOCOUPLE INPUT
The Type T Thermocouple input uses true internal cold junction compensation. For accurate
measurements, thermocouple grade copper and constantan wire must be used from the
thermocouple to the rear panel thermocouple connector. Figure 31 shows the rear panel
thermocouple connector. The mating connector is an Omega NMP-T-M (included with each
Data Acquisition Card), or equivalent. If it is desired to use shielded thermocouple wire, which is
recommended, the shield drain wire can be connected to the RTD or thermistor shield pin.
The Type T Thermocouple has a range of 0 to 371°C. The use of a thermocouple is
recommended in oxidizing, reducing, inert or vacuum atmosphere within its temperature range.
Figure 31 Rear Panel Type T Thermocouple Connector