OPERATING INSTRUCTIONS NI 9853 2-Port, High-Speed CAN Module
These operating instructions describe how to use the National Instruments (NI) 9853 module. For information about installing, configuring, and programming your system, refer to your system documentation. The NI 9853 module requires the NI 9853 software to be installed. The latest version of the NI 9853 software is located at ni.com/downloads. The safety guidelines and specifications in this document are specific to the NI 9853.
Safety Guidelines for Hazardous Locations The NI 9853 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 9853 in a potentially explosive environment. Not following these guidelines may result in serious injury or death.
For Zone 2 applications, install a protection device between the CAN signals and the NI 9853 CAN pins. The device must prevent the CAN Port-to-COM voltage from exceeding 55 V if there is a transient overvoltage condition. Caution Special Conditions for Safe Use in Europe This equipment has been evaluated as EEx nA II T4 equipment under DEMKO Certificate No. 03 ATEX 0324020X. Each module is marked II 3G and is suitable for use in Zone 2 hazardous locations.
one or both of the COM pins. Each port also has an optional shield pin, SHLD, that can be connected to a shielded CAN cable. Connecting SHLD may improve signal integrity and EMC performance in a noisy environment. CAN0 of the NI 9853 is internally powered, and therefore requires no external power supply. CAN1 requires an external power supply of +8 to +25 V to operate. Supply power to the VSUP pin of CAN1 from the CAN bus.
Table 1. Pin Assignments for CAN0 Connector 6 7 8 9 1 2 3 4 5 NI 9853 Operating Instructions Pin Signal 1 No Connection (NC) 2 CAN_L 3 COM 4 NC 5 SHLD 6 COM 7 CAN_H 8 NC 9 NC 6 ni.
Table 2. Pin Assignments for CAN1 Connector 6 7 8 9 1 2 3 4 5 © National Instruments Corp.
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.
Bus Cable Length CAN_H CAN Node CAN_H Rt Rt CAN_L CAN Node CAN Node CAN_H CAN_L CAN_L CAN_H CAN_L Stub Length CAN Node Figure 1. CAN Bus Topology and Termination Resistor Locations © National Instruments Corp.
Connecting a CAN Bus to the NI 9853 Each port of the NI 9853 can be connected to any location on a CAN bus. Figure 2 shows one example of the connection of CAN0 of the NI 9853 directly to one CAN node, and CAN1 directly to another CAN node. CAN1 requires an external power supply on the CAN bus. NI 9853 Operating Instructions 10 ni.
CAN Device (SHLD) (SHLD) CAN_H CAN_H Rt CAN_L Vsup CAN Cable (With Optional Shield) Rt CAN0 CAN_L Vsup COM COM CAN Device NI 9853 (SHLD) (SHLD) CAN_H CAN_H Rt CAN_L Vsup COM CAN Cable (With Optional Shield) Rt CAN1 CAN_L + – External Power Supply Vsup COM Figure 2. Connecting Both Ports of the NI 9853 to CAN Buses © National Instruments Corp.
Cabling Requirements for NI 9853 This section deals with cabling specifications, termination resistors, cable lengths, and the number of CAN nodes that can exist in a system. Cable Specifications Cables should meet the physical medium requirements specified in ISO 11898, shown in Table 3. Belden cable (3084A) meets all of those requirements, and should be suitable for most applications. Table 3.
Termination Resistors The termination resistors (Rt) should match the nominal impedance of the CAN cable, and therefore comply with the values in Table 4. Table 4. Termination Resistor Specification Characteristic Termination resistor, Rt Value 100 Ω min, 120 Ω nominal, 130 Ω max Condition Minimum power dissipation: 220 mW Cable Lengths The allowable cable length is affected by the characteristics of the cabling and the desired bit transmission rates.
Number of CAN Nodes The maximum number of nodes depends on the electrical characteristics of the nodes on the network. If all of the nodes meet the requirements of ISO 11898, at least 30 nodes may be connected to the bus. Higher numbers of nodes may be connected if the electrical characteristics of the nodes do not degrade signal quality below ISO 11898 signal level specifications. The electrical characteristics of the NI 9853 allow at least 110 CAN ports on a network.
+5 V +5 V_ISO Iso Pwr COM CAN_H CAN_L GND CAN Transceiver Rx Tx Rx Tx CAN Controller Rx Tx Rx Tx CAN Controller CAN0 Vsup Ext Pwr + Supply _ COM CAN_H CAN_L +5 V Reg CAN Transceiver CAN1 Figure 3. NI 9853 Hardware Overview © National Instruments Corp.
Sleep Mode (CompactRIO Only) You can enable sleep mode for the CompactRIO system in software. In sleep mode, the system consumes less power and may dissipate less heat. Typically, when a system is in sleep mode, you cannot communicate with the modules. Refer to the Specifications section for more information about power consumption and thermal dissipation. This system sleep mode should not be confused with the NI 9853 Transceiver Mode Sleep property, which sets only the CAN port to sleep mode.
Specifications The following specifications are typical for the range –40 to 70 °C unless otherwise noted. High-Speed CAN Characteristics Transceiver........................................ Philips TJA1041 Max baud rate ................................... 1 Mbps CAN_H, CAN_L bus lines voltage............................................... –27 to +40 VDC Supply voltage range (VSUP) CAN0 ......................................... N/A CAN1 ......................................... +8 to +25 VDC MTBF ..........
Power Requirements Power consumption from chassis Active mode Transmitting ......................... 625 mW max Receiving ............................. 400 mW max Sleep mode ................................. 25 μW max Thermal dissipation (at 70 °C) Active mode ............................... 1 W max Sleep mode ................................. 250 mW max Physical Characteristics If you need to clean the module, wipe it with a dry towel. Weight............................................... Approx.
Safety Maximum Voltage1 Connect only voltages that are within these limits. Port-to-COM..................................... –27 to +40 VDC max, Measurement Category I Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers equipment. This category is for measurements of voltages from specially protected secondary circuits.
Isolation Voltages Port-to-port Withstand.................................... 500 Vrms, verified by a dielectric withstand test, 5 s Continuous ................................. 60 VDC, Measurement Category I Port-to-earth ground Withstand.................................... 500 Vrms, verified by a dielectric withstand test, 5 s Continuous .................................
Note For UL and other safety certifications, refer to the product label, or visit ni.com/certification, search by model number or product line, and click the appropriate link in the Certification column. Hazardous Locations U.S. (UL) .......................................... Class I, Division 2, Groups A, B, C, D, T4; Class I, Zone 2, AEx nA II T4 Canada (C-UL) ................................. Class I, Division 2, Groups A, B, C, D, T4; Class I, Zone 2, Ex nA II T4 Europe (DEMKO).........................
Environmental CompactRIO modules are intended for indoor use only. For outdoor use, mount the CompactRIO system in a suitably rated enclosure. Refer to the installation instructions for the chassis you are using for more information about meeting these specifications. Operating temperature ...................... –40 to 70 °C Storage temperature .......................... –40 to 85 °C Ingress protection.............................. IP 40 Operating humidity...........................
Operating shock (IEC 60068-2-27).............................. 30 g, 11 ms half sine, 50 g, 3 ms half sine, 18 shocks at 6 orientations Operating vibration, sinusoidal (IEC 60068-2-6) ..............
CE Compliance This product meets the essential requirements of applicable European Directives, as amended for CE marking, as follows: • 2006/95/EC; Low-Voltage Directive (safety) • 2004/108/EC; Electromagnetic Compatibility Directive (EMC) Note Refer to the Declaration of Conformity (DoC) for this product for any additional regulatory compliance information. To obtain the DoC for this product, visit ni.
For additional environmental information, refer to the NI and the Environment Web page at ni.com/environment. This page contains the environmental regulations and directives with which NI complies, as well as other environmental information not included in this document. Waste Electrical and Electronic Equipment (WEEE) EU Customers At the end of their life cycle, all products must be sent to a WEEE recycling center.
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