National Instruments NI 9213 User manual

NI-9213
Getting Started
2023-08-02

Contents
NI-9213 Getting Started. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
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NI-9213 Getting Started

NI-9213 Getting Started
Connector Types
The NI-9213 is available in two types: push-in spring terminal and spring terminal.
The push-in type spring terminal connector is black and orange. The spring terminal
connector is black. NI-9213 refers to both types unless the two types are specified.
Dierences between the two types of spring terminal connectors are noted by the
connector color.
NI-9213 Block Diagram
Each channel passes through a dierential filter and then is multiplexed and
sampled by a 24-bit analog-to-digital converter (ADC). The channels share a
common ground, COM, that is isolated from other modules in the system.
Figure 1. Input Circuitry for One Channel of the NI-9213
TC+
TC–
COM
NI 9213
Input
Impedance
Open
Thermocouple
Detection
Current
Filtered
Differential
Amplifier
and
Multiplexer
Isolated
ADC
39 MΩ
39 MΩ
NI-9213 (Black Connector) Pinout
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NC
TC0+
TC2+
TC4+
TC6+
TC8+
TC10+
TC12+
TC14+
COM
TC1+
TC3+
TC5+
TC7+
TC9+
TC11+
TC13+
TC15+
TC0–
NC
TC1–
TC3–
TC5–
TC7–
TC9–
TC11–
TC13–
TC15–
TC2–
TC4–
TC6–
TC8–
TC10–
TC12–
TC14–
COM
Table 1. Signal Descriptions
Signal Description
COM Common reference connection
NC No connection
TC+ Positive thermocouple connection
TC- Negative thermocouple connection
NI-9213 (Black/Orange Connector) Pinout
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
NC
TC0+
TC2+
TC4+
TC6+
TC8+
TC10+
TC12+
TC14+
COM
TC1+
TC3+
TC5+
TC7+
TC9+
TC11+
TC13+
TC15+
TC0–
NC
TC1–
TC3–
TC5–
TC7–
TC9–
TC11–
TC13–
TC15–
TC2–
TC4–
TC6–
TC8–
TC10–
TC12–
TC14–
COM
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Table 2. Signal Descriptions
Signal Description
COM Common reference connection
NC No connection
TC+ Positive thermocouple connection
TC- Negative thermocouple connection
Connecting Wires to the NI-9213 (Black Connector)
What to Use
■ NI-9213 spring-terminal connector
■0.08 mm to 1.0 mm (28 AWG to 18 AWG) copper conductor wire with
7 mm (0.28 in) of insulation stripped from the end
■Flathead screwdriver with a 2.3 mm x 1.0 mm (0.09 in. x 0.04 in.) blade,
included with the NI-9213
What to Do
Complete the following steps to connect wires to the spring-terminal connector.
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1. Insert the screwdriver into a spring clamp activation slot to open the
corresponding connector terminal.
2. Press a wire into the open connector terminal.
3. Remove the screwdriver from the activation slot to clamp the wire into place.
Connecting Wires to the NI-9213 with Push-in Style
Spring Terminal (Black/Orange Connector)
What to Use
■NI-9213 (black/orange connector)
■0.14 mm to 1.5 mm (26 AWG to 16 AWG) copper conductor wire with
10 mm (0.394 in.) of insulation stripped from the end
■Ferules (optional)
What to Do
Refer to the following table for how to insert a wire into a terminal depending on
what type of wire you are using or if you are using a ferrule.
Option Description
When using a solid wire or stranded wire with a
ferrule
Push the wire into the terminal when using a
solid wire or stranded wire with a ferrule
When using a stranded wire without a ferrule Press the push button and then push the wire
into the terminal
Note You must use 2-wire ferrules to create a secure connection when
connecting more than one wire to a single terminal.
Connecting a Thermocouple
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Thermocouple
TC–
COM
TC+
Shield
NI 9213
Vreference
Connect the shield to a common-mode voltage reference on the thermocouple.
A valid common-mode voltage reference is a voltage that is within ±1.2 V of the
common-mode voltage of all the connected thermocouples
High-Vibration Application Connections
If your application is subject to high vibration, NI recommends that you use the
NI-9940 backshell kit to protect connections to the NI-9213.
Common-Mode Voltage
The NI-9213 common-mode range is the maximum voltage between any channel
and COM. If COM is not connected, then the common-mode voltage range is the
maximum voltage between any two channels. The NI-9213 measures the common-
mode voltage level of each channel and returns a warning in the soware if the
signal is outside the common-mode voltage range.
Open Thermocouple Detection
Each channel has an open thermocouple detection (OTD) circuit, which consists of
a current source between the TC+ and TC- terminals. If an open thermocouple is
connected to the channel, the current source forces a full-scale voltage across the
terminals.
Input Impedance
Each channel has a resistor that produces an input impedance between the TC and
COM terminals. The gain and oset errors resulting from the source impedance of
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NI-9213 Getting Started

connected thermocouples are negligible for most applications. Thermocouples with
a higher lead resistance can introduce more significant errors.
Minimizing Thermal Gradients
Changes in the ambient air temperature near the front connector or a thermocouple
wire conducting heat directly to terminal junctions can cause thermal gradients.
Observe the following guidelines to minimize thermal gradients and improve the
system accuracy.
■Use small-gauge thermocouple wire. Smaller wire transfers less heat to or
from the terminal junction.
■Avoid running thermocouple wires near hot or cold objects.
■Minimize adjacent heat sources and air flow across the terminals.
■Keep the ambient temperature as stable as possible.
■Make sure the NI-9213 terminals are facing forward or upward.
■Keep the NI-9213 in a stable and consistent orientation.
■Allow the thermal gradients to settle aer a change in system power or
in ambient temperature. A change in system power can happen when the
system powers on, the system comes out of sleep mode, or you insert/remove
modules.
■Run thermocouple wiring together near the spring-terminal connector to
keep the wires at the same temperature.
■If you connect any extension wires to thermocouple wires, use wires made
of the same conductive material as the thermocouple wires.
■Use the NI-9440 backshell kit.
Thermocouple Measurement Accuracy
Thermocouple measurement errors depend partly on the following factors.
■Type of thermocouple
■Accuracy of the thermocouple
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■Temperature that you are measuring
■Resistance of the thermocouple wires
■Cold-junction temperature
Note Use the autozero channel to compensate for oset errors.
Cold-Junction Accuracy
Heat dissipated by adjacent C Series modules or nearby heat sources can
cause errors in thermocouple measurements by heating the NI-9213 terminals
to a dierent temperature than the cold-junction compensation sensor. Thermal
gradient across the terminals can cause the terminals of dierent NI-9213 channels
to be at dierent temperatures, which creates accuracy errors and aects the
relative accuracy between channels.
The temperature measurement accuracy specifications include errors caused by the
thermal gradient across the NI-9213 terminals for configurations with the NI-9213
terminals facing forward or upward.
Autozero Channel
The NI-9213 has an internal autozero channel, which can be subtracted from each
thermocouple reading to compensate for oset errors. Use of the autozero channel
is optional, however the NI-9213 specifications assume that autozero is applied to
every sample. Refer to the documentation for the soware that you are using with
the NI-9213 for information about using the autozero channel.
Timing Modes
The NI-9213 supports high-resolution and high-speed timing modes. High-
resolution timing mode optimizes accuracy and noise and rejects power line
frequencies. High-speed timing mode optimizes sample rate and signal bandwidth.
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