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How to read parameters (PIDs) from several modules at once

Posted: Tue Mar 28, 2017 6:38 am
by FORScan
FORScan v2.3.8 has new feature - ability to read PIDs from different modules simultaneously (aggregated output). Although we tried to make this function most transparent for end users, there are few things to mention.

In order to implement the aggregated output, a virtual module "All" was added to the Read PID section. Main page of the section has no any significant specific, PIDs are not marked as related to some module. But differencies can be found inside of the PID setup dialog:
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Main distinction is that every parameter has its' module abbreviation as a prefix. So user can easily identify the PID's module. However, parameter navigation may be more difficult because of large number of PIDs in the list: in contrast to regular modules that rarely have more than 100 PID's, the virtual module may have up to thousand. So, to simplify the navigation, operator can use the filter string. For example, if we type 'ABS' there, we will filter out everything except parameters that gave the ABS abbreviation:
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One more difference: only "Read" mode is available. The "Control" mode cannot be selected as the mode selection box is disabled.

Some other limitations have to be considered while using the aggregated output. Sometimes switching between buses may be quite resource consuming and require hundreds of milliseconds. So in many cases, using the All module may lead to serious performance dropdown (PIDs reading speed/frrequency). FORScan shows a warning when the PIDs setting dialog for All module is opened at the first time:
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In some cases using aggregated output is difficult, impossible or senseless. FORScan may show additional warnings in such cases. For example:
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In this example (Mondeo Mk3 TDCi) adding FIP/ICU PIDs usually doesn't make sense, as the egnine will stop at the first switch between modules. The aggregated output will continue to work, but ICU parameters on stopped engine are hardly interesting for anyone. In such cases we recommend to either avoid using aggregated output (so diagnose the ICU/FIP separately), or use PCM PIDs instead of ICU ones (many ICU parameters for this car are replicated to PCM).