Controlled Aria Network Board

This Board is a prototype of CAN system which allows to analyse all the data transferring process and to capture it with oscilloscope. In order to compare High-CAN and Low-CAN data streams is better to use dual-channel oscilloscope.

For the "A" CAN bus node pin#1 is H-CAN and pin#2 is L-CAN. For the CAN bus node B pin#4 is CAN-H and pin#5 is CAN-L. The very first pattern we captured is on the photo below:

On the pattern the two channels which are high and low oppose each other like they are reflected via mirror. This is reliability feature and they both carry the information according the manufacturer protocol.
You can see that the channel 1 is pulled up from 0 volts to 1 volt. And channel 2 is pulled down from 1.6 volts to ground. According to wire diagram and oscilloscope readings CAN-H is blue colour and CAN-L is yellow colour.

Patterns captured for the different devices in switch on position:

1.Right indicator:

2.Left Indicator:

3.Rear Wiper:

4.Stoplights:

5.Fuel pump:

6.Revers lights:

Pay attention to the pattern areas circled with red colour. These are visible changes in comparison to the first pattern which are actually our data transmitted through the system to the particular device it is addressed. This is a way how the signal can be examined and devices communication process can be controlled and analysed in diagnostics purposes.

Using the wiring diagram we can identify the input pin#7 for the RH Indicator. From this pin via limiting resistor R5 signal goes on the pin#6 of the IC 18F258. Checking the output we can see that IC9 activates the transistor U7 from collector of which signal goes to the RH Indicator.
Rear Wiper path starts on the pin#9, through the limiting resistor to the pin#25 of MC 18F258. Checking the output we can see that the transistor U14 switches the relay RL4a control circuit which in its turn switches the wiper on.

Voltage regulator for the Node A as well as voltage regulator for the Node B is built on the basis of LM7805 with voltage out 5 volts. Input voltage comes on to the leg #1 of the regulator, feedback from the pin#3 comes onto the pin#2. Diode prevents discharge spike from the smoothing signal capacitor. Both regulators supply voltage to the IC in the Node A and Node B. These are : pin#20 of MC 18F258, pin#3 of IC4,  pin#16 of IC3 and pin#14 of MCP 2505, pin#5 of IC5.

If we look at any inputs, for instance FUEL PUMP, pin#8 input, we'll track the signal from input to output. In our case it goes via limiting resistor R6 to the pin#7 of microcontroller VP18F258 which is pre-programmed. This microcontroller transforms the input signal into the binary code combinations that is actually our data signal. Through the transceiver IC4 ( UC5350N ) the CAN-H and CAN-L signals go to the Node B. Where, via IC5  ( UC5350N ) transceiver signal comes to the inputs of driver MCP2505. This driver activates control circuit of RL3A relay by means of the transistor U13. Once it happens, the switching circuit of the relay RL3b connects the FUEL PUMP to the circuit and it delivers fuel.