National Instruments NI 9219 User manual

OPERATING INSTRUCTIONS
NI 9219
4-Channel, 24-Bit, Universal Analog Input Module

NI 9219 Operating Instructions 2 ni.com
These operating instructions describe how to use the National
Instruments 9219. For information about installing, configuring,
and programming the system, refer to the system documentation.
Visit ni.com/info and enter the info code rdsoftwareversion
to determine which software you need for the modules you are
using.
Note The safety guidelines and specifications in this
document are specific to the NI 9219. The other
components in the system might not meet the same safety
ratings and specifications. Refer to the documentation for
each component in the system to determine the safety
ratings and specifications for the entire system.
Safety Guidelines
Operate the NI 9219 only as described in these operating
instructions.
Hot Surface This icon denotes that the component may be
hot. Touching this component may result in bodily injury.

© National Instruments Corp. 3 NI 9219 Operating Instructions
Safety Guidelines for Hazardous Voltages
If hazardous voltages are connected to the module, take the
following precautions. A hazardous voltage is a voltage greater
than 42.4 Vpk or 60 VDC to earth ground.
Caution Ensure that hazardous voltage wiring is
performed only by qualified personnel adhering to
local electrical standards.
Caution Do not mix hazardous voltage circuits and
human-accessible circuits on the same module.
Caution Make sure that devices and circuits connected to
the module are properly insulated from human contact.
Caution When module terminals are hazardous voltage
LIVE (>42.4 Vpk/60 VDC), you must ensure that devices
and circuits connected to the module are properly insulated
from human contact. You must use the NI 9972 connector
backshell kit to ensure that the terminals are not accessible.

NI 9219 Operating Instructions 4 ni.com
Figure 1 shows the NI 9972 connector backshell.
Figure 1. NI 9972 Connector Backshell
Safety Guidelines for Hazardous Locations
The NI 9219 is suitable for use in Class I, Division 2, Groups A, B,
C, D, T4 hazardous locations; Class I, Zone 2, AEx nC IIC T4
hazardous locations; and nonhazardous locations only. Follow
these guidelines if you are installing the NI 9219 in a potentially
explosive environment. Not following these guidelines may result
in serious injury or death.
Caution Do not disconnect I/O-side wires or connectors
unless power has been switched off or the area is known
to be nonhazardous.

© National Instruments Corp. 5 NI 9219 Operating Instructions
Caution Do not remove modules unless power has been
switched off or the area is known to be nonhazardous.
Caution Substitution of components may impair
suitability for Class I, Division 2.
Caution For Zone 2 applications, install the system
in an enclosure rated to at least IP 54 as defined by
IEC 60529 and EN 60529.
Special Conditions for Marine Applications
Some modules are Lloyd’s Register (LR) Type Approved for
marine applications. To verify Lloyd’s Register certification, visit
ni.com/certification and search for the LR certificate, or
look for the Lloyd’s Register mark on the module.
Caution To meet radio frequency emission requirements
for marine applications, use shielded cables and install
the system in a metal enclosure. Suppression ferrites
must be installed on power supply inputs near power
entries to modules and controllers. Power supply and
module cables must be separated on opposite sides of
the enclosure and must enter/exit through opposing
enclosure walls.

NI 9219 Operating Instructions 6 ni.com
Wiring the NI 9219
The NI 9219 has four 6-terminal connectors that provide
connections for four analog input channels. Connect the positive
signal of the signal source to the positive input signal terminal (HI)
and the negative signal of the signal source to the negative input
signal terminal (LO). Use the excitation terminals if your sensor
requires a separate excitation connection. Refer to Table 1 for the
signal names and Table 2 for the terminal assignments for each
mode. Refer to the NI 9219 Circuitry section for information about
connections in each mode.

© National Instruments Corp. 7 NI 9219 Operating Instructions
Table 1. Signal Names
Module Terminal
Signal
Name Signal Description
1T+ TEDS Data
2T– TEDS COM
3EX+/HI*Positive excitation or
input signal
4HI Positive input signal
5EX–/LO*Negative excitation or
input signal
6LO Negative input signal
*Depending on the mode, terminals 3 and 5 are either the excitation signals or the
input signals.
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
6
Ch 0
Ch 1
Ch 2
Ch 3

NI 9219 Operating Instructions 8 ni.com
Table 2. Terminal Assignments
Mode
Terminal
123456
Voltage T+ T–—HI LO —
Current T+ T–HI —LO —
4-Wire Resistance T+ T–EX+ HI EX–LO
2-Wire Resistance T+ T–HI —LO —
Thermocouple T+ T–—HI LO —
4-Wire RTD T+ T–EX+ HI EX–LO
3-Wire RTD T+ T–EX+ —EX–LO
Quarter-Bridge T+ T–HI —LO —
Half-Bridge T+ T–EX+ HI EX–—
Full-Bridge T+ T–EX+ HI EX–LO
Digital In T+ T–—HI LO —
Open Contact T+ T–HI —LO —

© National Instruments Corp. 9 NI 9219 Operating Instructions
Connecting Wires to the NI 9219 Connectors
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
connectors. 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 2 for an illustration of
connecting wires to the NI 9219.
Figure 2. Connecting Wires to the NI 9219 Connectors

NI 9219 Operating Instructions 10 ni.com
Wiring TEDS Channels
The NI 9219 supports only Class II TEDS sensors. Connect the two
TEDS lines to
TEDS Data (T+) and TEDS COM (T–) and ensure
that neither T+ nor T– is tied in common to any of the signal inputs
(terminals 3 through 6) on the NI 9219. Visit ni.com/info and
enter the info code rdteds for information about TEDS sensors.
Grounding and Shielding Considerations
You can connect ground-referenced or floating signal sources to
the NI 9219. If you make a floating connection between the signal
source and the NI 9219, make sure the voltages on the positive and
negative connections are within the channel-to-earth working
voltage range to ensure proper operation of the NI 9219. Refer to
the Specifications section for more information about operating
voltages and overvoltage protection.
Note For best signal quality, National Instruments
recommends using shielded cables and twisted pair
wiring whenever possible.
Figures 3 and 4 illustrate connecting grounded and floating signal
sources to the NI 9219 in Voltage mode.

© National Instruments Corp. 11 NI 9219 Operating Instructions
Figure 3. Connecting a Grounded Signal Source to the NI 9219
Figure 4. Connecting a Floating Signal Source to the NI 9219
+
–
Twisted-Pair
Wiring
VSIG
VSIG Ground
Reference
Signal Source Shielding
HI
LO
NI 9219
+
–
Twisted-Pair
Wiring
VSIG
Signal Source Shielding
HI
LO NI 9219

NI 9219 Operating Instructions 12 ni.com
NI 9219 Timing Options
The NI 9219 supports four different timing options that are
optimized for different types of applications by using different
ADC conversion times. High Speed is optimized for high speed at
the expense of noise rejection, Best 60 Hz Rejection is optimized
for rejection of 60 Hz noise, Best 50 Hz Rejection is optimized for
rejection of 50 Hz noise, and High Resolution is optimized for
maximum overall noise rejection and provides good rejection of
50 Hz and 60 Hz noise. Refer to the Specifications section for more
information.
NI 9219 Circuitry
The NI 9219 is channel-to-channel isolated. Four 24-bit
analog-to-digital converters (ADCs) simultaneously sample all
four analog input channels. An excitation circuit is enabled for
all input modes that require excitation. The ADC and excitation
circuits are reconfigured in each mode to accommodate each type
of sensor. Refer to Figure 5 for an illustration of the input circuitry
for one channel of the NI 9219.

© National Instruments Corp. 13 NI 9219 Operating Instructions
Figure 5. Input Circuitry for One Channel
Voltage and Current Modes
In Voltage and Current modes, connect the signal source to the
NI 9219 across the HI and LO terminals. The current is computed
from the voltage that the ADC measures across an internal shunt
resistor. Refer to Figure 6 for an illustration of the connections.
Figure 6. Connections in Voltage, Current, and Digital In Modes
Isolated
ADC
TEDS
1
2
+
–
CHx 3
6
NI 9219
FilterMUX
Current mode
HI
LO
ADC
IR
SH
NI 9219
Voltage/Digital In modes
HI
LO
ADC
V
+
–
NI 9219

NI 9219 Operating Instructions 14 ni.com
4-Wire Resistance and 4-Wire RTD Modes
4-Wire Resistance and 4-Wire RTD modes source a current, which
varies based on the resistance of the load, between the EX+ and
EX– terminals. The measured resistance is computed from the
resulting voltage reading. These modes are not affected by lead
wire resistance because a negligible amount of current flows across
the HI and LO terminals due to the high input impedance of the
ADC. Refer to Figure 7 for an illustration of the connections.
Figure 7. Connections in 4-Wire Resistance and 4-Wire RTD Modes
3-Wire RTD Mode
3-Wire RTD mode sources a current, which varies based on the
resistance of the load, between the EX+ and EX– terminals. This
mode compensates for lead wire resistance in hardware if all the
LO
HI
EX–
RTD/
Resistor
Wire
Wire
Wire
I
ADC
I
EX+
Wire
NI 9219

© National Instruments Corp. 15 NI 9219 Operating Instructions
lead wires have the same resistance. A gain of 2x is applied to the
voltage across the negative lead wire and the ADC uses this voltage
as the negative reference to cancel the resistance error across the
positive lead wire. Refer to Figure 8 for an illustration of the
connections.
Figure 8. Connections in 3-Wire RTD Mode
2-Wire Resistance and Quarter-Bridge Modes
In 2-Wire Resistance and Quarter-Bridge modes, connect the
two ends of the resistor or gauge to the NI 9219 across the HI and
LO terminals. These modes source a current, which varies based on
the resistance of the load, between the HI and LO terminals. The
resulting resistance is computed from the voltage measurement.
2-Wire Resistance and Quarter-Bridge modes do not compensate
LO
EX+
EX–
RTD
Wire
Wire
Wire
I
x2
ADC
I
I
NI 9219

NI 9219 Operating Instructions 16 ni.com
for lead wire resistance. Refer to Figure 9 for an illustration of the
connections.
Figure 9. Connections in 2-Wire Resistance and Quarter-Bridge Modes
Half-Bridge and Full-Bridge Modes
Half-Bridge and Full-Bridge modes use the internal voltage
excitation to set the input range of the ADC and return voltage
readings that are proportional to the excitation level. The internal
excitation voltage is nominally 2.5 V but it varies based on the
resistance of the sensor. Refer to the Specifications section for
more information about excitation levels.
In Half-Bridge mode, the HI input is referenced to EX–.
In Full-Bridge mode, the ADC reads the HI and LO inputs
differentially. Refer to Figure 10 for an illustration of the
connections.
LO
R
Wire
Wire I
ADC
I
HI
NI 9219

© National Instruments Corp. 17 NI 9219 Operating Instructions
Figure 10. Connections in Half-Bridge and Full-Bridge Modes
Thermocouple Mode
In Thermocouple mode, connect the positive end of the
thermocouple to HI and the negative end of the thermocouple to
LO. This mode uses the ±125 mV range of the ADC to return a
voltage reading. Use shielded cables and twisted pair wiring and
ground the shielded cables. Each channel has a built-in thermistor
for cold-junction compensation (CJC) calculations. For improved
CJC sensor accuracy, operate the NI 9219 in a stable temperature
1 The dotted line representsthe portion of the circuit that isconnected
only in Full-Bridge mode.
HI
LO
EX+
EX– NI 9219
R
1
R
2
R
3
R
4
ADC
Wire
Wire
1

NI 9219 Operating Instructions 18 ni.com
environment and avoid placing heat sources near the module
or its connectors. Refer to the Specifications section for more
information about accuracy. The NI 9219 does not support open
thermocouple detection. Refer to Figure 11 for an illustration of
the connections.
Figure 11. Connections in Thermocouple Mode
Digital In Mode
Digital In mode has a 60 V unipolar threshold that you can set in
software. Refer to the software documentation for information
about setting this threshold. Digital In mode is supported only in
CompactRIO systems. Refer to Figure 6 for an illustration of the
connections.
Open Contact Mode
Open Contact mode sources a current between the HI and LO
terminals and determines if the two terminals are open or closed
based on the measured current through the terminals. When the
HI
LO
TC ADC
NI 9219
+
–

© National Instruments Corp. 19 NI 9219 Operating Instructions
circuit is open, make sure no more than ±60 V is sourced across the
switch. Open Contact mode is supported only in CompactRIO
systems. Refer to Figure 12 for an illustration of the connections.
Figure 12. Connections in Open Contact Mode
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 documentation for information
about support for sleep mode. You can enable sleep mode in
software. Refer to the driver software documentation for more
information.
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.
HI
LO
ADC I
NI 9219

NI 9219 Operating Instructions 20 ni.com
Binary Data
NI 9219 modules in the system return calibrated binary data when
used in a CompactRIO chassis. For these modules, you can convert
the data to engineering units in software. Refer to the software
documentation for information about converting data. When used
in a CompactDAQ chassis, NI 9219 modules automatically return
the data in terms of engineering units. Refer to the software
documentation for more information.
Excitation Protection
The NI 9219 excitation circuit is protected from overcurrent and
overvoltage fault conditions. The circuit is automatically disabled
in the event of a fault condition. Whenever possible, channels
automatically recover after the fault is removed. Refer to the
software documentation for information on how an excitation fault
is displayed and handled.
Specifications
The following specifications are typical for the range –40 to 70 °C
unless otherwise noted.