National Instruments NI 9852 User manual

GETTING STARTED GUIDE
NI 9852
2-Port, Low-Speed/Fault-Tolerant CAN Module

This document explains how to connect to the NI 9852.
The NI 9852 module requires the latest NI 985x software to be
installed. The latest version of the NI 985x 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 9852. 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 9852 only as described in this document.
Caution Do not operate the NI 9852 in a manner not
specified in this document. Product misuse can result in
a hazard. You can compromise the safety protection
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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 9852 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 9852 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.
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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 Division 2 and Zone 2 applications,
install a protection device between the external power
supply and the Vsup pin. The device must prevent the
Vsup-to-COM voltage from exceeding 50 V if there is
a transient overvoltage condition.
Caution For Zone 2 applications, install a protection
device between the CAN signals and the NI 9852 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 9852 has been evaluated as Ex nA IIC T4 Gc equipment
under DEMKO Certificate No. 03 ATEX 0626664X and is
IECEx UL 14.0089X certified. Each NI 9852 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 9852 in Gas Group IIC hazardous locations, you must use the
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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.
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 9852
The NI 9852 has two 9-pin male D-Sub connectors that provides
connections to a CAN bus. Each port on the NI 9852 has pins for
CAN_H and CAN_L, to which you connect the CAN bus signals.
Connect these signals using twisted-pair cable.
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Each port has two isolated 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 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.
Both of the ports on the NI 9852 require an external power
supply of +8 to +25 V to operate. Supply power from the CAN
bus to the VSUP0 pin on CAN0, and the VSUP1 pin on CAN1.
Pinouts for CAN0 and CAN1 of the NI 9852 are listed in Tables
1 and 2.
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Table 1. Pin Assignments for CAN0
Connector Pin Signal
6
7
8
9
1
2
3
4
5
1 No Connection (NC)
2 CAN_L
3 COM0
4 NC
5 SHLD
6 COM0
7 CAN_H
8 NC
9 VSUP0
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Table 2. Pin Assignments for CAN1
Connector Pin Signal
6
7
8
9
1
2
3
4
5
1 No Connection (NC)
2 CAN_L
3 COM0
4 NC
5 SHLD
6 COM0
7 CAN_H
8 NC
9 VSUP0
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
Connecting a CAN Bus to the NI 9852
You can connect each port of the NI 9852 to any location on a
CAN bus. Figure 2 shows one example of connecting CAN0 of
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the NI 9852 directly to one CAN node, and CAN1 directly to
another CAN node. CAN0 and CAN1 require an external power
supply on the CAN bus.
Figure 2. Connecting Both Ports of the NI 9852 to CAN Buses
CAN1
CAN Device
CAN0
NI 9852
CAN
Cable
(With
Optional
Shield)
(SHLD)
CAN_H
CAN_L
Vsup1
COM1
(SHLD)
CAN_H
CAN_L
Vsup1
COM1
CAN Device
CAN
Cable
(With
Optional
Shield)
(SHLD)
CAN_H
CAN_L
Vsup0
COM0
(SHLD)
CAN_H
CAN_L
Vsup0
COM0
+
–
External
Power
Supply
+
–
External
Power
Supply
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