The Opto 22 CAN Integration Kit for PAC Project - Transmit and Receive provides sample PAC Control subroutines and charts so that your Opto 22 SNAP PAC System equipped with one or more SNAP-SCM-CAN2B
modules can communicate with devices on a Controller Area Network (CAN). The SNAP-SCM-CAN2B is a high-speed serial communications module that can transmit to and receive data from CAN devices.
When transmit functionality is enabled, all transmit and receive data between the module and the SNAP PAC brain or controller are ASCII encoded and frame delimited for robust communications.
The sample strategy in the integration kit runs on an Opto 22 SNAP PAC controller. The CAN Transport Protocol (described in the CAN RX/TX Integration Kit for PAC Project Technical Note
, form 2151) provides direct access to a SNAP-SCM-CAN2B which implements the CAN transport and physical layers. Access to higher layer protocols—such as J1939, NMEA 2000, CANopen, and DeviceNet—needs to be implemented by the customer.
The sample subroutines show you the PAC Control commands to use for CAN communication and the format of data in them. The charts illustrate how to call the subroutines. Using PAC Control, you can easily add to or modify the subroutines and charts to match your system’s requirements.
This integration kit requires SNAP-SCM-CAN2B modules with firmware R2.0b or higher. With this firmware the module can both send and receive CAN data; with earlier firmware the module only receives data.
To add transmit capability to an existing module, download the newer firmware
and then follow steps in the PAC Manager User's Guide
(form 1704) to update the firmware.
For modules with firmware R1.0d and lower that only receive data, use a different integration kit (part number PAC-INT-CAN-RX