Choosing an RTD or Thermistor Measurement System

Benchtop or Field Measurements

A CompactDAQ system consists of a chassis, NI C Series I/O modules, and software. Chassis can connect to a host computer over USB, Ethernet, or 802.11 WiFi or operate stand-alone with a built-in controller. With over 50 measurement-specific modules and 1-, 4-, and 8-slot chassis, CompactDAQ provides a flexible, expandable platform to meet the needs of any electrical or sensor measurement system.

• Multiple timing engines for multiple acquisition rates
• Advanced counter functionality from NI-STC3 technology

Embedded Data-Logging Measurements

CompactDAQ controllers offer a high-performance platform for embedded measurements and data logging. Controllers feature an integrated computer and nonvolatile storage, so that CompactDAQ can be deployed without an external computer.

• Includes Intel multicore processing, up to 32 GB nonvolatile storage, and 2 GB RAM
• Simultaneously stream continuous measurements with sample rates up to 1 MS/s per channel

Extreme Ruggedness and Advanced Control

CompactRIO is a reconfigurable embedded control and acquisition system. The CompactRIO hardware architecture includes a reconfigurable FPGA chassis and an embedded controller. CompactRIO can be used in a variety of embedded control and monitoring applications.

• A variety of reconfigurable chassis featuring an FPGA for custom timing, analysis, and control
• Open embedded architecture with small size and extreme ruggedness

NI 9217 Module

The NI 9217 C Series RTD analog input module features four channels and 24 bits of resolution for 100 Ω RTD measurements. You can configure the NI 9217 for two different sampling rate modes. With the high-sampling-rate mode, you can sample at up to 400 S/s (100 S/s per channel). Using the high-resolution mode, you can sample at 5 S/s (1.25 S/s per channel) with built-in 50/60 Hz noise rejection.

The NI 9217, compatible with 3- and 4-wire RTD measurements, automatically detects the type of RTD (3- or 4-wire) connected to the channel and configures each channel for the appropriate mode. The module can provide 1 mA of current excitation per channel and has less than a 1 °C accuracy error over its entire operating temperature range. The NI 9217 contains NIST-traceable calibration and includes a channel-to-earth ground double isolation barrier for safety, noise immunity, and high-common-mode voltage range. 

NI 9219 Measurement System 

The NI 9219 measurement system measures four universal channels at 100 S/s with 24-bit resolution, sending data to a host PC over USB, Ethernet, or 802.11 WiFi.

The NI 9219 is a 4-channel universal C Series module designed for multipurpose testing in any CompactDAQ or CompactRIO chassis. With the NI 9219, you can measure several signals from sensors such as strain gages, RTDs, thermocouples, load cells, and other powered sensors. The channels are individually selectable, so you can perform a different measurement type on each of the four channels. Measurement ranges differ for each type of measurement and include up to ±60 V for voltage and ±25 mA for current. See the manual for detailed specifications and ranges.

NI 9216 Module

The NI 9216 RTD analog input C Series module features eight channels and 24 bits of resolution for PT100 RTD measurements. You can configure the NI 9216 for two different sampling rate modes. With the high-sampling-rate mode, you can sample at up to 400 S/s (50 S/s per channel). Using the high-resolution mode, you can sample at 5 S/s (0.625 S/s per channel) with built-in 50/60 Hz noise rejection. The NI 9216, compatible with 3- and 4-wire RTD measurements, automatically detects the type of RTD (3- or 4-wire) connected to the channel and configures each channel for the appropriate mode. The module provides 1 mA of current excitation per channel and has less than a 1.0 °C accuracy error over its entire operating temperature range. The NI 9216 includes a channel-to-earth ground double isolation barrier for safety, noise immunity, and high common-mode voltage range. NI provides calibration services for the NI 9216.

NI 9226 Module

The NI 9226 RTD analog input C Series module features eight channels and 24 bits of resolution for PT1000 RTD measurements. You can configure the NI 9226 for two different sampling rate modes. With the high-sampling-rate mode, you can sample at up to 400 S/s (50 S/s per channel). Using the high-resolution mode, you can sample at 5 S/s (0.625 S/s per channel) with built-in 50/60 Hz noise rejection. The NI 9226, compatible with 3- and 4-wire RTD measurements, automatically detects the type of RTD (3- or 4-wire) connected to the channel and configures each channel for the appropriate mode. The module provides 0.1 mA of current excitation per channel and has less than a 1.1 °C accuracy error over its entire operating temperature range. The NI 9226 includes a channel-to-earth ground double isolation barrier for safety, noise immunity, and high common-mode voltage range. NI provides calibration services for the NI 9226.

NI 9219 Measurement System 

The NI 9219 can theoretically be used for thermistor measurements though it was not specifically designed for them. The KnowledgeBase article Thermistor Measurements Using the NI 9219 covers the details and limitations of using the NI 9219 with thermistors.

Ready-made RTDs offer solutions for cost-sensitive temperature measurement applications. Each RTD element is sealed in an Alumina tube with three Teflon-coated leads, and can measure up to 400 °F (204 °C). Teflon offers good resistance to abrasion and moisture. Each RTD is sold individually and is available in lead lengths of 1 m (39.4 in.) and 2 m (78.7 in.).

Features

• 3-wire leads
• 1 m and 2 m lengths
• Ideal for starter and educational applications
• Measure up to 400 °F (204 °C)
• Platinum 100 Ω at 0 °C (alpha=0.00385)

NI field-cuttable RTDs are ideal for a wide variety of temperature applications. With field-cuttable RTDs, you can cut the probe to your desired length, from 3.5 in. to 24 in. (8.9 cm to 61 cm). Therefore, you can use one stock of RTDs for all of your temperature measurements to reduce inventory cost and production downtime. These RTD probes can measure up to 900 °F (482 °C). For applications using thermal wells, the optional spring-loaded fitting reduces installation time while ensuring contact with the thermal well. Each probe has glass braid insulated leads and is sold individually.

Features

• Reduces inventory cost and downtime
• 3-wire
• Measures up to 900 °F (482 °C)
• Platinum 100 Ω at 0 °C (alpha=0.00385)
• Probes can be field cut to within 3.5 in. of tip (maximum length 24 in.)
• Lead length is 6 in.