Garmin GTR 200 Manual de instalación descargar pdf (Pagina 19)

190-01553-00 GTR 200 Installation Manual

Rev. G Page 2-5

2.7.2 CAN Bus Considerations

The CAN (controller area network) bus (Figure 2-1) is an interface format used to establish

communication between several LRUs in the G3X system. Each end of the CAN bus “backbone” must be

terminated. Each node length (distance from CAN bus backbone to each LRU) must be 0.3 meter or less

in length (keeping the node lengths as short as practicable is recommended). There is no minimum node

length.

A GTR 200 can be connected in a G3X system that uses a GDU 37X or GDU 46X with CAN bus or

RS232, the CAN bus is preferred.

NOTE

Use only two CAN bus terminations per installation (even if provided more than two from

associated G3X installation kits). Using less than or more than two terminations (one at

each end of the backbone) will make the CAN bus unusable or unreliable.

Figure 2-1 CAN Bus Configuration

The following items should be considered when installing/removing/replacing LRU’s on the CAN bus:

1. CAN bus node connections must be made on the connector of each LRU that connects to the CAN

bus, do not tie CAN bus nodes from individual LRUs together into a single connection point.

2. Keep all node lengths as short as practicable, and allow only one ‘lengthy’ node if possible.

NOTE

The 120 Ω termination resistors described in the preceding paragraphs are “built-in” to

the termination method shown in Figure D-2

. Do not install a separate “discrete” 120 Ω

resistor to terminate the CAN bus.

CAN Bus Backbone

CAN HI

CAN LOW

(Node #1)

LRU

(Node #2)

LRU

(Node #3)

LRU

(Node #n)

LRU

Node Length

0.3 meter max.

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 83 84

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Garmin GTR 200 Manual de instalación Pagina 19