National Instruments NI 9882 User manual

OPERATING INSTRUCTIONS
NI 9882
1-Port DeviceNet Module

NI 9882 Operating Instructions 2 ni.com
These operating instructions describe how to use the National
Instruments (NI) 9882 module. For information about installing,
configuring, and programming your system, refer to your system
documentation. The NI 9882 module requires the latest
NI-DeviceNet software to be installed. The latest version of the
NI-DeviceNet software is available at ni.com/downloads.
Note The safety guidelines and specifications in this
document are specific to the NI 9882. The other
components in your system may not meet the same safety
ratings and specifications. Refer to the documentation for
each component in your system to determine the safety
ratings and specifications for the entire system.
Safety Guidelines
Operate the NI 9882 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 9882 Operating Instructions
Safety Guidelines for Hazardous Locations
The NI 9882 is suitable for use in Class I, Division 2, Groups A, B,
C, D, T4 hazardous locations; Class I, Zone 2, AEx nA II T4 and
Ex nA II T4 hazardous locations; and nonhazardous locations only.
Follow these guidelines if you are installing the NI 9882 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.
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
CompactRIO system in an enclosure rated to at least
IP 54 as defined by IEC 60529 and EN 60529.

NI 9882 Operating Instructions 4 ni.com
Caution For Zone 2 applications, install a protection
device between the CAN signals and the NI 9882 CAN
pins. The device must prevent the CAN Port-to-COM
voltage from exceeding 55 V if there is a transient
overvoltage condition.
Special Conditions for Safe Use in Europe
This equipment has been evaluated as Ex nA II T4 equipment
under DEMKO Certificate No. 07 ATEX 0626664X. Each module
is marked II 3G and is suitable for use in Zone 2 hazardous
locations.
Wiring the NI 9882
The NI 9882 has one 9-pin male D-Sub connector that provides
connections to a CAN bus. The NI 9882 has pins for CAN_H and
CAN_L, to which you connect the CAN bus signals. Connect these
signals using twisted-pair cable.
The port has two common pins (COM) that are internally
connected to the module’s isolated reference and serve as the
reference ground for CAN_H and CAN_L. You can connect the
CAN bus reference ground (sometimes referred to as CAN_V–) to

© National Instruments Corp. 5 NI 9882 Operating Instructions
one or both COM pins. The port also has an optional shield pin,
SHLD, that you can connect to a shielded CAN cable. Connecting
SHLD may improve signal integrity and EMC performance in a
noisy environment.
Caution You must use a UL listed ITE power supply
marked LPS with the NI 9882.
The NI 9882 requires an external power supply in the range of
+9 to +30 V to operate. Supply power to the NI 9882 VSUP pin.
Note Power on VSUP is required for DeviceNET
operation.
The NI 9882 pinout is listed in Table 1.
The NI 9882 features software-selectable bus termination for
High-Speed CAN transceivers. On the NI 9882, you can enable
120 termination resistors between CAN_H and CAN_L through
an API call. Table 3 lists recommended termination resistor values.

NI 9882 Operating Instructions 6 ni.com
Table 1. Pin Assignments for the NI 9882
Connector Pin Signal
1No Connection (NC)
2CAN_L
3COM
4NC
5SHLD
6COM
7CAN_H
8NC
9 VSUP
6
7
8
9
1
2
3
4
5

© National Instruments Corp. 7 NI 9882 Operating Instructions
CAN Bus Topology and Termination
A CAN bus consists of two or more CAN nodes cabled together.
The CAN_H and CAN_L pins of each node are connected to the
main CAN bus cable through a short connection known as a “stub.”
The pair of signal wires, CAN_H and CAN_L, constitutes a
transmission line. If the transmission line is not terminated,
each signal change on the bus causes reflections that may cause
communication errors. Because the CAN bus is bidirectional, both
ends of the cable must be terminated. However, this requirement
does not mean that every node on the bus should have a termination
resistor; only the two nodes at the far end of the cable should have
termination resistors.
Figure 1 shows a simplified diagram of a CAN bus with multiple
CAN nodes and proper termination resistor (Rt) locations.

NI 9882 Operating Instructions 8 ni.com
Figure 1. CAN Bus Topology and Termination Resistor Locations
CAN
Node
CAN
Node
CAN
Node
RtRt
CAN
Node
CAN_H
CAN_L
CAN_H
CAN_L
CAN_H
CAN_L
CAN_H
CAN_L
Bus Cable Length
Stub
Length

© National Instruments Corp. 9 NI 9882 Operating Instructions
Connecting a CAN Bus to the NI 9882
You can connect the NI 9882 port to any location on a CAN bus.
Figure 2 shows one example of connecting the NI 9882 directly to
one CAN node.
Figure 2. Connecting the NI 9882 to a CAN Device
Cabling Requirements for the NI 9882
This section deals with cabling specifications, termination
resistors, cable lengths, and the number of CAN nodes that can
exist in a system.
CAN0 NI 9882
CAN Device
Rt
CAN
Cable
(With
Optional
Shield)
(SHLD)
CAN_H
CAN_L
Vsup
COM
Rt
(SHLD)
CAN_H
CAN_L
Vsup
COM

NI 9882 Operating Instructions 10 ni.com
Cable Specifications
Cables should meet the physical medium requirements specified
in ISO 11898, shown in Table 2. Belden cable (3084A) meets all
these requirements and should be suitable for most applications.
Termination Resistors
The termination resistors (Rt) should match the nominal
impedance of the CAN cable and therefore comply with the values
in Table 3. The onboard, software-selectable termination has a
nominal value of 120 . If you are not using the onboard
termination, use the values listed in Table 3.
Table 2. ISO 11898 Specifications for Characteristics of a CAN_H and
CAN_L Pair of Wires
Characteristic Value
Impedance 95 minimum, 120 nominal, 140 maximum
Length-related
resistance
70 m/m nominal
Specific line delay 5 ns/m nominal