NI-9217 Getting Started
- Updated2023-02-17
- 3 minute(s) read
NI-9217 Getting Started
Connecting the NI-9217
The NI-9217 provides connections for four RTD channels.
NI-9217
Block Diagram
- RTD channels share a common ground that is isolated from other modules in the system.
- Each RTD channel is filtered and then sampled by a 24-bit analog-to-digital converter (ADC).
NI-9217 Pinout
Signal | Description |
---|---|
COM | Common reference connection to isolated ground |
EX | Excitation source connection |
RTD+ | Positive resistance temperature detector connection |
RTD- | Negative resistance temperature detector connection |
NI-9217 Connection Guidelines
- Make sure that devices you connect to the NI-9217 are compatible with the module specifications.
- You must use 2-wire ferrules to create a secure connection when connecting more than one wire to a single terminal on the NI-9217.
- For the NI-9217 with push-in spring terminal, push the wire into the terminal when using a solid wire or a stranded wire with a ferrule.
- For the NI-9217 with push-in spring terminal, open the terminal by pressing the push button when using stranded wire without a ferrule.
High-Vibration Application Connections
If your application is subject to high vibration, NI recommends that you follow these guidelines to protect connections to the NI-9217:
- Use ferrules to terminate wires to the detachable connector.
- Use the NI-9939 connector backshell kit.
Connecting 3-Wire and 4-Wire RTDs
You can connect any combination of 3-wire or 4-wire RTDs to the NI-9217. Each NI-9217 channel contains circuitry that automatically detects the type of RTD connected to the channel. The NI-9217 scans all four input channels and automatically configures each channel for the appropriate mode. In 4-wire mode, the EX terminal is a 1 mA current source. In 3-wire mode, the RTD+ terminal is a 1 mA current source. The NI-9217 compensates for the error that lead resistance causes in 3-wire mode.
If you are using a 4-wire RTD, connect EX to the positive lead of the RTD. If you are using a 3-wire RTD, do not connect the RTD to the EX terminal.
For the best measurement results when using the NI-9217 with a 3-wire RTD, use equal-length wires between the RTD+ terminal and the RTD and between the COM terminal and the RTD. Also, keep the lead resistance within 5% of the nominal RTD value. The NI-9217 accuracy specifications account for this lead error.