Start exploring the tool by searching for simple parameters, such as turn indicators data, steering wheel position, and door position. The easier the process in which a particular unit is involved, the easier it is to influence changes in its system indications. That means you can identify the right parameter among many others more quickly.
More than two thousand different messages are transmitted through the CAN bus at speeds of up to 1 Mbit per second. How to find the right data in this amount of information?
The engine speed, accelerator pedal position and ABS sensor readings are frequently displayed at the top of the parameter list, as they are the fundamental to the operation of the transmission and safety systems. The information about the windscreen wipers or the trunk lid is not the priority for the correct operation of the main systems. Therefore, it is displayed in the bottom lines of the parameter list.
This means that the more important the item you are trying to find readings from is, the higher it is on the list. You can physically affect the part or unit and search for changes in the lines corresponding to its importance.
How to see the changing parameters online and compare the values second by second? Select the longer period of highlighting indicators using the slider box in the upper right corner.
The default setting is set to update the data instantly. However, if you know that the point you are applying to may change the data point less frequently, set a longer period, e.g., 5 or 7 seconds.
Wait until the data is gray and then start looking for the indicator. You are likely to find the changes among the others quickly. This will help you to remove the unnecessary data and concentrate on identifying the necessary data.
For example, the engine speed data changes every second, unlike the fuel level data, which is almost always the same at standstill. So, when you are looking at the list of the ID lines, you are more likely to see the changes in engine speed than in the fuel level. For this reason, change the highlight period and start influencing the data for the point you are looking for.
During the process of defining the IDs, you can select or eliminate those ID lines that contain unnecessary information for you. Just click on the eye icon and that line will go to the end of the list. You can put it back in place at any time by tapping the crossed-out eye icon again.
It also happens that a line of one identifier may contain the information about several elements. For example, the information about low beam, high beam or parking lights is in the adjacent bytes.
Next, if you need to send or copy this data, assign a tag to that identifier. To do this, copy the ID line and split up the necessary bytes into different tags. It's just easier to do it this way.
The data is displayed in hex format in the CAN Scanner tool. However, when more than one byte is being processed, there is a problem of reading data in different formats: from high to low and vice versa. In the CAN Scanner tool, it is possible to choose the direction of data reading before writing to the tag and sending to the server. It is enough to specify the reading direction at the end of the line, after selecting the necessary bytes, and then specify the tag in which the data will be written.
If there is not enough time to find all the data exactly at the place, it is possible to enable the log recording, to affect the indicators, to save the log for further playback an infinite number of times. It is better to start logging before the beginning of affecting the units of the car, so that the log shows the moment of the beginning and the end of the affect, and not a piece of the log taken out of context. And in order not to mix up the data, use the color zones, which will be explained in the next paragraph.
Use color markers to color the period of the log entry to find the desired ID in the log. For example, in the log entry, color the period when the engine speed was changed in yellow, when the brake pedal was pressed in red, and when the trailer gate was opened or closed in green.
This will help in further analysis. You will not have to "look for a needle in a haystack", or rather look for one byte among hundreds of others. The highlighted period will allow to narrow the search down to a few dozens of bytes.
When recording a CAN log, it may be necessary to stop recording to check the sensors, reconfigure the device, or make changes to the indication (refill the fuel or lower the tires). For this purpose, you can use the recording pauses. Keep in mind, that when analyzing the log later, you may find gaps, i.e., gaps in the recording, where the data you need may have fallen into.
For example, there is an indicator that changes once every 7 seconds, and you paused at the sixth second. It means that this indicator was not recorded, it was lost.
Pauses in the recording can cause the loss of the necessary data. The playback will pause for a specified period and the search may be more difficult.
That is why it is better to use pauses when recording as rarely as possible. It is better to have a full and large recorded log than a short and useless log.