Vansco VMM3120, User Manual

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User Guide 43
Communication
The VMM3120 uses the Controller Area Network (CAN) communication when
communicating with other modules on the vehicle, or with a personal computer.
6.1. Controller area network
The VMM3120 has 1 Controller Area Network (CAN) communication port(s)
available. The VMM3120 hardware provides controller area network (CAN)
communication according to the SAE J1939 specification, making the VMM3120
compatible with any CAN-based protocol through software.
CAN communication is used to communicate the status of multiple modules that
are connected together in the same network.
6.1.1. J1939 CAN Capabilities
The CAN communicates information at a rate of 250 kbps. Lack of regular CAN
communication is an indication that there is either a problem with a module in the
network, or a problem with the CAN bus.
CAN communication provides a feature called Wake on CAN, which is a way to
provide power control to the VMM3120.
Wake on CAN provides a low-current sleep mode that turns on the VMM3120
when a CAN message is received by the module.
It is not possible to filter messages that are used to turn on the VMM3120 using
Wake on CAN. For this reason, any message will turn on the VMM3120. The
application software must be written to determine how the VMM3120 will behave
when it is turned on.
6. Communication