Zilla FAQ18 Feb 2008 10:24 pm

The best diagnostic tool when a car under-performs is to read the “Operating Status” that the Hairball can spit out using the DAQ (Data Acquisition) display. The DAQ display is a diagnostic tool that was originally only made for development so it is not terribly user-friendly, but many people have learned to use it despite that.
To view DAQ data, you need a serial terminal connected to the Hairball that you can carry with you while driving.
The DAQ display, when running, feeds out ten new lines of data per second. By watching the display line on the bottom of the screen it will look like one string of values that automatically updates. If the the issue of concern happens while driving (such as low power) then this should be done with a helper to view the DAQ while another person drives.

When using the Palm Pilot to view the DAQ with the original setup, the lines can get longer than 32 characters (especially when using other that DAQ4) and will line-wrap, making it hard to read the display. In order to avoid this, the line width setting in the Ptelnet Terminal menu can be set from 32 to 64. When this has been done then the screen will scroll left, center and right by tapping on the left, center and right side of the display. When switching to a 64 character line with, the screen will go blank if you tap the right side of the screen when the data displayed is not long (such as a menu), so, if the screen is unexpectedly blank, be sure to tap the left side of the main display to return to the left side of the display.

Basics of using the DAQ are covered in the owners manual where it says this:
Start the DAQ in the Special menu by typing “Q1” or “Q2” etc., followed by a return.
DAQ data is displayed 10 lines per second in Hex format with spaces between data. Data is approximate and the scaling values vary.
Press the space bar to exit DAQ mode. DAQs may change with new code versions.

For our purposes of diagnosis we will use DAQ4. When starting DAQ4 with the car off, it will display something like this:

State: 1311
How may I help you?Q4
41 00 01 00 00 0B 00 1E 20 SFSV
41 00 01 00 00 0B 00 1E 20 SFSV
41 00 01 00 00 0B 00 1E 20 SFSV
41 00 01 00 00 0B 00 1E 20 SFSV
And so on, until the whole screen is full of lines of data.
The 9th value, 20, just before the jumble of letters at the end is the Operating Status. This is the most important number to us. If we look up 20 in the Diagnostic Trouble Codes in the Hairball manual we will see that it equates to “waiting for key”.

Next we turn on the key and the data on DAQ4 changes to:
41 00 01 00 00 0B 00 1E 21 SMFSV
Again, the 9th value concerns us, it is 21 which equates to “waiting for start signal”, So we turn the key to start and get this:
41 00 01 C8 00 93 00 1F 23 SOMFS
where the 23 indicates that it is waiting for throttle input. Unless we happen to have a faulty throttle potentiometer or are resting our foot on the throttle in which case we get:
51 00 01 C8 00 93 00 1F 22 SOMFS
where the 22 indicates that it has not yet seen a zero pot and therefore will not run. This is a feature that protects the vehicle from driving away uncontrolled on startup if the potbox is maladjusted.
As we get underway on the road, we may see something like this:
55 0B 07 C8 07 8E 07 27 30 OMFS
The 30 indicates that there are no active limits on the controller aside from the duty cycle requested by the pedal position.
As we drive we will likely see some of this:
A0 07 58 C8 22 86 1B 29 27 OMFS
where the 27 indicates that a standard motor current limit is active. This is either because the motor is drawing the amount of the motor current limit setting, or if we are at low throttle positions then the throttle current limit is insuring a smooth driving experience.
Another common mode is this:
BF 08 64 9E 26 83 1E 29 26 OMFS
The 26 indicates that the battery voltage limit is active. In this case the battery voltage has sagged to the limit set in the battery menu. If the car is running slower than expected at this point then either the batteries are soft, or the voltage setting is too conservative. Of course, trying to get too much power out of batteries can destroy them, so adjust with care.
Other codes are also possible, those should be self explanatory when looked up in the Hairball manual.

The other values in the DAQ can also be useful but being in hexadecimal format are a bit more confusing to decipher. For more details of the value scaling, please see the FAQ entry titled “What are the details for using data from the DAQ?”

2 Responses to “The car won’t start or runs slowly. How to use the DAQ.”

  1. on 07 Oct 2010 at 2:11 am Peter Travers

    I cannot get into the DAQ at the special menu. I try and type Q1 or Q2 but the menu is redisplayed when I type the Q and before I can type the 1 or do the return. I am running hyperterm on a windows 7 laptop

  2. on 07 Oct 2010 at 7:29 am Otmar

    Try uppercase Q