National Instruments 9861 User manual

GETTING STARTED GUIDE
NI 9861
1-Port, Low-Speed/Fault Tolerant CAN Module
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This document explains how to connect to the NI 9861.

The NI 9861 module requires the latest NI-XNET software to be
installed. The latest version of the NI-XNET software is at
ni.com/downloads.
Note Before you begin, complete the software and
hardware installation procedures in your chassis
documentation.
Note The guidelines in this document are specific to
the NI 9861. The other components in the system might
not meet the same safety ratings. Refer to the
documentation for each component in the system to
determine the safety and EMC ratings for the entire
system.
Safety Guidelines
Operate the NI 9861 only as described in this document.
Hot Surface This icon denotes that the component
may be hot. Touching this component may result in
bodily injury.
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Caution Do not operate the NI 9861 in a manner not
specified in this document. Product misuse can result in
a hazard. You can compromise the safety protection
built into the product if the product is damaged in any
way. If the product is damaged, return it to NI for
repair.
Safety Guidelines for Hazardous Locations
The NI 9861 is suitable for use in Class I, Division 2, Groups A,
B, C, D, T4 hazardous locations; Class I, Zone 2, AEx nA IIC T4
and Ex nA IIC T4 hazardous locations; and nonhazardous
locations only. Follow these guidelines if you are installing the
NI 9861 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.
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Caution Substitution of components may impair
suitability for Class I, Division 2.
Caution For Division 2 and Zone 2 applications,
install the system in an enclosure rated to at least IP54
as defined by IEC/EN 60079-15.
Caution For Zone 2 applications, install a protection
device between the CAN signals and the NI 9861 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 Hazardous Locations Use in
Europe and Internationally
The NI 9861 has been evaluated as Ex nA IIC T4 Gc equipment
under DEMKO Certificate No. 07 ATEX 0626664X and is
IECEx 14.0089X certified. Each NI 9861 is marked II 3G and
is suitable for use in Zone 2 hazardous locations, in ambient
temperatures of -40 °C ≤ Ta ≤ 70 °C. If you are using the NI 9861
in Gas Group IIC hazardous locations, you must use the device in
an NI chassis that has been evaluated as Ex nC IIC T4, Ex IIC
T4, Ex nA IIC T4, or Ex nL IIC T4 equipment.
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Caution You must make sure that transient
disturbances do not exceed 140% of the rated voltage.
Caution The system shall only be used in an area of
not more than Pollution Degree 2, as defined in
IEC 60664-1.
Caution The system shall be mounted in an
ATEX/IECEx-certified enclosure with a minimum
ingress protection rating of at least IP54 as defined in
IEC/EN 60079-15.
Caution The enclosure must have a door or cover
accessible only by the use of a tool.
Wiring the NI 9861
The NI 9861 has one 9-pin male D-Sub connector that provides
connections to a CAN bus. The NI 9861 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 isolated common pins (COM) that are internally
connected to the module’s isolated reference and serve as the
NI 9861 Getting Started Guide | © National Instruments | 5

reference ground for CAN_H and CAN_L. You can connect the
CAN bus reference ground (sometimes referred to as CAN_V-) to
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 9861.
The NI 9861 requires an external power supply of +9 to +30 V to
operate. Supply power from the CAN bus to the VSUP pin.
Note Power on VSUP is required for CAN operation.
The NI 9861 pinout is listed in Table 1.
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Table 1. Pin Assignments for the NI 9861
Connector Pin Signal
6
7
8
9
1
2
3
4
5
1 No Connection (NC)
2 CAN_L
3 COM
4 NC
5 SHLD
6 COM
7 CAN_H
8 NC
9 VSUP
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
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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. Every device on a low-speed/fault-tolerant
CAN network requires a termination resistor for each CAN data
line: RRTH for CAN_H and RRTL for CAN_L.
Figure 1 shows a simplified diagram of a low-speed/fault-tolerant
CAN bus with termination resistor placements.
Figure 1. CAN Bus Topology and Termination Resistor Locations
RTL CAN_L RTH CAN_H RTL CAN_L RTH CAN_H RTL CAN_L RTH CAN_H
CAN_H
CAN_L
Low-speed/Fault-Tolerant
CAN Device
Low-speed/Fault-Tolerant
CAN Device
Low-speed/Fault-Tolerant
CAN Device
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Connecting a CAN Bus to the NI 9861
You can connect each port of the NI 9861 to any location on a
CAN bus. Figure 2 shows one example of connecting the
NI 9861 directly to one CAN node.
Figure 2. Connecting Both Ports of the NI 9861 to CAN Buses
NI 9861
CAN Device
CAN
Cable
(With
Optional
Shield)
(SHLD)
CAN_H
CAN_L
Vsup
COM
(SHLD)
CAN_H
CAN_L
Vsup
COM
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Cabling Requirements for the NI 9861
Cable Specifications
Cables should meet the physical medium requirements specified
in ISO 11898, shown in the following table. Belden cable
(3084A) meets all these requirements and should be suitable for
most applications.
Table 2. ISO 11898 Specifications for Characteristics of a CAN_H and
CAN_L Pair of Wires
Characteristic Value
Length-related resistance 90 mΩ/m nominal
Length-related capacitance: CAN_L and ground,
CAN_H and ground, CAN_L and CAN_H
30 pF/m nominal
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