National Instruments 9213E User manual

OPERATING INSTRUCTIONS AND SPECIFICATIONS
NI 9213E
16-Channel Thermocouple Input Module

NI 9213E Operating Instructions and Specifications 2 ni.com
This document describes how to use the National Instruments 9213E
and includes dimensions, terminal assignments, and specifications for
the NI 9213E. Visit ni.com/info and enter rdsoftwareversion
to determine which software you need for the modules you are using.
For information about installing, configuring, and programming the
system, refer to the system documentation. Visit ni.com/info and
enter cseriesdoc for information about C Series documentation.
Caution National Instruments makes no electromagnetic
compatibility (EMC) or CE marking compliance claims
for the NI 9213E. The end-product supplier is responsible
for conformity to any and all compliance requirements.
Caution The NI 9213E must be installed inside a suitable
enclosure prior to use. Hazardous voltages may be present.

© National Instruments Corp. 3 NI 9213E Operating Instructions and Specifications
NI 9213E Dimensions
The following figure shows the dimensions of the NI 9213E.
Figure 1. NI 9213E Dimensions in Millimeters (Inches)
73.4 (2.89)
0.0 (0.00)
26.7 (1.05)
58.4 (2.30) 66.0 (2.60)
0.0 (0.00)

NI 9213E Operating Instructions and Specifications 4 ni.com
Connecting the NI 9213E
The NI 9213E has a 36-terminal detachable spring-terminal
connector that provides connections for 16 thermocouple channels.
Figure 2. NI 9213E Terminal Assignments
NC
TC0+
TC1+
TC2+
TC3+
TC4+
TC5+
TC6+
TC7+
TC8+
TC9+
TC10+
TC11+
TC12+
TC13+
TC14+
TC15+
COM
NC
TC0–
TC1–
TC2–
TC3–
TC4–
TC5–
TC6–
TC7–
TC8–
TC9–
TC10–
TC11–
TC12–
TC13–
TC14–
TC15–
COM
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

© National Instruments Corp. 5 NI 9213E Operating Instructions and Specifications
You can connect thermocouple input signals to the NI 9213E.
Connect the positive lead of the thermocouple to the TC+ terminal
and the negative lead of the thermocouple to the TC– terminal. If
you are unsure which of the thermocouple leads is positive and
which is negative, check the thermocouple documentation or the
thermocouple wire spool.
The NI 9213E also has two common terminals, COM, that are
internally connected to the isolated ground reference of the
module. If you are using a shielded thermocouple, connect COM
to the shield and the shield to a common-mode voltage reference of
the thermocouple. A common-mode voltage reference is a voltage
that is within ±1.2 V of the common-mode voltage of the
thermocouple. If you are using a floating thermocouple or a
thermocouple within ±1.2 V of earth ground, connect COM and the
shield to earth ground. The shield grounding methodology can vary
depending on the application. Refer to Figure 3 for an illustration
of a typical shielding configuration.

NI 9213E Operating Instructions and Specifications 6 ni.com
Figure 3. Connecting a Shielded Thermocouple Input Signal to the NI 9213E
Thermocouple
TC–
COM
TC+
Shield
NI 9213E
Vreference

© National Instruments Corp. 7 NI 9213E Operating Instructions and Specifications
Connecting Wires to the NI 9213E Connector
Use a flathead screwdriver with a blade smaller than 2.3 × 1.0 mm
(0.09 × 0.04 in.) to connect wires to the detachable spring-terminal
connector. Insert the screwdriver into a spring clamp activation slot
and press a wire into the corresponding connector terminal, then
remove the screwdriver to clamp the wire into the terminal. Refer
to the Specifications section for more information about
spring-terminal wiring. Refer to Figure 4 for an illustration of
connecting wires to the NI 9213E.
Figure 4. Connecting Wires to the NI 9213E Connector

NI 9213E Operating Instructions and Specifications 8 ni.com
NI 9213E Circuitry
Each channel of the NI 9213E passes through a differential filter
and then is multiplexed and sampled by a 24-bit analog-to-digital
converter (ADC). Each channel also 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. Refer to Figure 5 for an illustration of
the input circuitry for one channel of the NI 9213E.
The NI 9213E multiplexes 16 thermocouple input channels,
1 cold-junction compensation (CJC) channel, and 1 autozero
channel to a single ADC. Each channel has a resistor that produces
an input impedance between the TC+and COM terminals and
between the TC– and COM terminals. The gain and offset errors
resulting from the source impedance of connected thermocouples
are negligible for most applications. Thermocouples with a higher
lead resistance can introduce more significant errors. Refer to the
Specifications section for more information about errors resulting
from source impedance.

© National Instruments Corp. 9 NI 9213E Operating Instructions and Specifications
Figure 5. Input Circuitry for One Channel of the NI 9213E
The channels share a common ground, COM, that is isolated from
other modules in the system. The NI 9213E 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 9213E
measures the common-mode voltage level of each channel and
returns a warning in the software if the signal is outside the
TC+
TC–
COM
NI 9213E
Input
Impedance
Open
Thermocouple
Detection
Current
Filtered
Differential
Amplifier
and
Multiplexer
Isolated
ADC
39 MΩ
39 MΩ

NI 9213E Operating Instructions and Specifications 10 ni.com
common-mode voltage range. Refer to the Specifications section
for more information about the common-mode voltage range.
The NI 9213E 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. Refer to the
Specifications section for more information about the
high-resolution and high-speed timing modes. Refer to the
software help for information about setting the timing mode, or
conversion time, in software. Visit ni.com/info and enter
cseriesdoc for information about C Series documentation.
Temperature Measurement Accuracy
Considerations
Temperature measurement errors depend partly on the
thermocouple type, the accuracy of the thermocouple, the
temperature being measured, and the cold-junction temperature.
Refer to the Temperature Measurement Accuracy section in the
Specifications for the errors for each thermocouple type when
connected to the NI 9213E. The errors do not account for the
accuracy of the thermocouple itself.

© National Instruments Corp. 11 NI 9213E Operating Instructions and Specifications
For the best accuracy results, keep temperature gradients across
NI 9213E terminals to a minimum and enable the autozero
channel. Refer to the Minimizing Thermal Gradients and Using the
Autozero Channel sections for more information.
Cold-Junction Temperature Measurement Accuracy
Heat dissipated by adjacent modules or other nearby heat sources
can cause errors in thermocouple measurements by heating up the
NI 9213E terminals to a different temperature than the
cold-junction compensation sensor. The thermal gradient across
the terminals can cause the terminals of different channels to be at
different temperatures, in which case the resulting measurement
creates errors not only in absolute accuracy but also in the relative
accuracy between channels. Refer to the Specifications section for
the cold-junction compensation accuracy specifications. The
thermocouple accuracy specifications include the errors caused by
the thermal gradient across the module terminals. Refer to the
Temperature Measurement Accuracy section in the Specifications
for the thermocouple accuracy specifications. Visit ni.com/info
and enter cjcdatascaling for more information about
isothermal errors and scaling CJC data.

NI 9213E Operating Instructions and Specifications 12 ni.com
Minimizing Thermal Gradients
Thermal gradients can be caused by changes in the ambient air
temperature near the front connector or by the thermocouple wire
if it conducts heat or cold directly to the terminal junctions. For the
best accuracy results, follow these guidelines for minimizing
thermal gradients:
• Use small-gauge thermocouple wire. Smaller wire transfers
less heat to or from the terminal junction.
• Run thermocouple wiring together near the spring-terminal
connector to keep the wires at the same temperature.
• Avoid running thermocouple wires near hot or cold objects.
• If you connect any extension wires to thermocouple wires,
use wires made of the same conductive material as the
thermocouple wires.
• Minimize adjacent heat sources and air flow across the
terminals.
• Keep the ambient temperature as stable as possible.

© National Instruments Corp. 13 NI 9213E Operating Instructions and Specifications
• Keep the module in a stable and consistent orientation.
• Allow the thermal gradients to settle after 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.
Using the Autozero Channel
The NI 9213E has an internal autozero channel to compensate for
the offset error. The NI 9213E specifications all assume the
autozero channel is on for every sample, however, you can choose
not to use the autozero channel in software. When the autozero
channel is on, the NI 9213E measures the autozero channel and
subtracts that measurement from the measurement of each
thermocouple channel. Refer to the software help for information
about using the autozero channel. Visit ni.com/info and enter
cseriesdoc for information about C Series documentation.

NI 9213E Operating Instructions and Specifications 14 ni.com
Sleep Mode
This module supports a low-power sleep mode. Support for sleep
mode at the system level depends on the chassis that the module is
plugged into. Refer to the chassis manual for information about
support for sleep mode. If the chassis supports sleep mode, refer to
the software help for information about enabling sleep mode. Visit
ni.com/info and enter cseriesdoc for information about
C Series documentation.
Typically, when a system is in sleep mode, you cannot
communicate with the modules. In sleep mode, the system
consumes minimal power and may dissipate less heat than it does
in normal mode. Refer to the Specifications section for more
information about power consumption and thermal dissipation.

© National Instruments Corp. 15 NI 9213E Operating Instructions and Specifications
Specifications
The following specifications are typical for the range –40 to 85 °C
internal to any enclosures unless otherwise noted.
Input Characteristics
Number of channels.......................... 16 thermocouple channels,
1 internal autozero channel,
1 internal cold-junction
compensation channel
ADC resolution................................. 24 bits
Type of ADC..................................... Delta-Sigma
Sampling mode ................................. Scanned
Voltage measurement range .............. ±78.125 mV
Temperature measurement ranges ....Works over temperature
ranges defined by NIST
(J, K, T, E, N, B, R, S
thermocouple types)

NI 9213E Operating Instructions and Specifications 16 ni.com
Timing modes
Common-mode voltage range
Channel-to-COM........................ ±1.2 V min
COM-to-earth ground................. ±250 V
Timing Mode
Conversion Time
(Per Channel)
Sample Rate*
(All Channels†)
High-resolution 55 ms 1 S/s
High-speed 740 μs75 S/s
* If you are using fewer than all channels, the sample rate might be faster.
The maximum sample rate = 1/(Conversion Time × Number of Channels),
or 100 S/s, whichever is smaller. Sampling faster than the maximum
sample rate may result in the degradation of accuracy.
† Including the autozero and cold-junction channels.

© National Instruments Corp. 17 NI 9213E Operating Instructions and Specifications
Common-mode rejection ratio
High-resolution mode (at DC and 50–60 Hz)
Channel-to-COM ................. 100 dB
COM-to-earth ground .......... >170 dB
High-speed mode (at 0–60 Hz)
Channel-to-COM ................. 70 dB
COM-to-earth ground .......... >150 dB
Input bandwidth
High-resolution mode................. 14.4 Hz
High-speed mode........................ 78 Hz
High-resolution noise rejection
(at 50 and 60 Hz) .............................. 60 dB
Overvoltage protection ..................... ±30 V between any
two inputs
Differential input impedance ............ 78 MΩ
Input current...................................... 50 nA
Input noise
High-resolution mode................. 200 nVrms
High-speed mode........................ 7 μVrms

NI 9213E Operating Instructions and Specifications 18 ni.com
Gain error
High-resolution mode................. 0.03% typ at 25 °C,
0.07% typ at –40 to 85 °C,
0.15% max at –40 to 85 °C
High-speed mode........................ 0.04% typ at 25 °C,
0.08% typ at –40 to 85 °C,
0.16% max at –40 to 85 °C
Offset error
High-resolution mode................. 4 μV typ, 6 μV max
High-speed mode........................ 14 μV typ, 17 μV max
Offset error
from source impedance..................... Add 0.05 μV per Ω, when
source impedance >50 Ω
Cold-junction compensation accuracy1
0 to 85 °C ................................... 0.8 °C typ, 1.7 °C max
–40 to 85 °C ............................... 1.1 °C typ, 2.1 °C max
1 The maximum errors assume an isothermal error of 1.3 °C. Refer to the
Cold-Junction Temperature Measurement Accuracy section for more information.

© National Instruments Corp. 19 NI 9213E Operating Instructions and Specifications
MTBF ............................................... 852,407 hours at 25 °C;
Bellcore Issue 2, Method 1,
Case 3, Limited Part Stress
Method
Note Contact NI for Bellcore MTBF specifications
at other temperatures or for MIL-HDBK-217F
specifications.
Temperature Measurement Accuracy
Measurement sensitivity1
High-resolution mode
Types J, K, T, E, N ............... <0.02 °C
Types B, R, S ....................... <0.15 °C
High-speed mode
Types J, K, T, E .................... <0.25 °C
Type N.................................. <0.35 °C
Type B .................................. <1.2 °C
Types R, S ............................ <2.8 °C
1 Measurement sensitivity represents the smallest change in temperature that a sensor
can detect. It is a function of noise. The values assume the full measurement range
of the standard thermocouple sensor according to ASTM E230-87.

NI 9213E Operating Instructions and Specifications 20 ni.com
Figures 6, 7, 8, 9, and 10 show the errors for each thermocouple
type when connected to the NI 9213E with the autozero channel
on. The figures display the maximum errors1over a full
temperature range and typical errors at room temperature. The
figures account for gain errors, offset errors, differential and
integral nonlinearity, quantization errors, noise errors, 50 Ωlead
wire resistance, and cold-junction compensation errors. The
figures do not account for the accuracy of the thermocouple itself.
1 The maximum errors assume an isothermal error of 1.3 °C. Refer to the
Cold-Junction Temperature Measurement Accuracy section for more information.