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For those inquiring about creating math channels:

Verifying software level

In order to create math channels, your software level must be level 4 and above. To verify the level at which your software is currently at, follow the below steps.

1. Open the Datalink II software on your PC
2. Select Security>Show/Edit Security Key List form the menu bar across the top
3. Locate your recorders serial number in the list of Currently Installed Serial Numbers (G2X units are 256, IQ3 units are 258, Sportsman units are 259)
4. Note the level associated with this number.

Should you have lower than 4, your’ll need to purchase the Datalink II Standard Upgrade part number 890-DL-STD in order create/add math channels.


Creating a math channel.

You can create math channels in either the downloaded run file, or in the main config file. The difference will be whether you wish for the math channel to continue to show up automatically in later uploaded run files or just in that one run file.

In order to have the math channel appear in future downloaded runs, the math channel must be created and saved in the config file. The downside to this is, to verify if the math channel works you are required to take a recording and download it to the PC.

As a good habit to get into, always start in a downloaded run file to ensure the math channel works as intended. Once this is verified, then create/copy this to the config file.

For this example, we’ll create a math channel to calculate slippage percent between two RPM channels. We’ll create this in a file downloaded from a drag race application. Other applications may find use this math channel by changing the source channels in it to match their needs.

Example: (('Engine RPM'-'DS RPM')/'Engine RPM')*100

The RPM source channels must already be in the file and in working order.

Well start by opening a saved run file on the PC.

Open the Datalink II software and select a run file to view by go to File>Open> select a run and click OK.

With the run file open, go to Edit>Channel Maintenance.

This opens the IO Channel Edit Window.

In this window, we’ll need to familiarize ourselves with the below areas,

List of Channel Names (left side of screen)
If you are going to edit an existing data channel select the channel to modify from the list of channel names by left clicking on the channel name. The name will become highlighted. If you a going to create a new math channel select the channel name in the list directly below where you want the new channel to appear.


Easy Insert Channel Command (button on right)
The Easy Insert Channel command is used to add new math channels to the car configuration and/or run data files. When the Easy Insert command is selected from the Channel Maintenance dialog box HID_CHANNEL_MAINTENANCE the Select Driver Name <and Type> selection box is displayed opened.

To add a new channel, first we’ll need to select a location in the channel listing to place this new channel. Ensure the location you select is below the source channels you plan to use in the math channel. If the location is higher than the source channels, the math channel may not operate correctly.

Select a location in the channel list.

Next select the Easy Insert Channel button on the right side of the screen.

The Select Driver Name <and Type> selection box will now open.

In this window, we’ll select the Calculation Driver, EXPR type. Click OK

The calculation driver allows a mathematical expression to be entered as a new channel. The expression can be any valid mathematical formula including parentheses for controlling the order of evaluation.

The Simple Expression Channel Parameters dialog box will now open.

This dialog box is used to enter the parameters required to define the new channel. The dialog box requires the following inputs:

Name
Enter the name of the channel being added. The name must contain an alpha character as the first letter in the name and must be unique. Two data channels can not be given the same name.

Expr
Enter the mathematical formula to be calculated. Named channel used in the expression such as ENGINE RPM must be enclosed in single quotes. To include a named channel in the expression, find the channel in the Currently Defined Channel list and double click on the channel name. The channel will automatically be inserted in the list at the current cursor position. The single quotes will automatically be placed around the name. You can also type the name and single quotes. At least one channel from the currently defined channel list must be included in the expression.

You can also use the Built in Functions as part of the expression. Select the function from the list by double clicking on the function name. Replace the x in the function call with the appropriate expression for evaluation.

The order of calculation is not guaranteed. Use parenthesis () in the expression to insure the calculations occur in the proper order.

Currently Defined Channels
List of currently defined channels. To select an item from this list double click on the desired channel. The channel name will be inserted in the expression at the current cursor position.

Built in Functions
This is a list of the supported math functions that can be used as part of the expression to be evaluated. Not used for this example.

Display _4_Digits before decimal points _2_after
Sets how the channel value will be displayed. The above example will display as 1234.12

Result Units
The engineering units associated with the channel. This is simple a label for future reference. (i.e. , RPM, DegF).

Minimum result Value
The value of the channel at the bottom of the graphics display. To display the Temp Average channel from 0 to 2000 degrees enter 0 as the minimum 2000 as the maximum.

Maximum
The value of the channel at the top of the graphics display.

Do not Display
Check this box to inhibit the channel from displaying in the channel list. This is useful to avoid displaying intermediate calculations used in a second calculation.


To enter in our calculation (calculate slippage percent between two RPM channels), type the following:

Name: Conv%Slip

Expr: (('Engine RPM'-'DS RPM')/'Engine RPM')*100

Display 4 Digits before decimal points 2 after

Result Unit: %

Minimum result value 0 Maximum: 200

Select OK

Assuming no errors in the process, the new channel will now be located in the channel listing located across the top of the run… Make sure the channel works in your run file. If everything looks good, go to File>Save to save the updated run file.

If you now wish to copy this to your config file, simply go to Edit>Copy Math Channels

Now open the config file by selecting File>Open Car Configuration, select your config file.

Once the config file is opened, go to Edit> Paste Math Channels

Go to File>Save to save the updated config file






Adding other math channels are done in similar fashion. Below are some other examples of math channels with their


Simple Expression Channels Examples(EXPR:)
Name: Tire RPM
Expr: 'DS RPM’ / final drive ratio
Minimum result value 0 Maximum: 1000

Name: Tire MPH
Expr: ( 'Tire RPM’ * (TireCircumference/12) * 60 ) / 5280
Minimum result value 0 Maximum: 200


Derivative Channels Examples
Name: DS RPM/Sec
Expr: 'DS RPM’
Minimum result value -1000 Maximum: 10000

Name: RPM/Sec
Expr: 'Enging RPM’
Minimum result value -1000 Maximum: 10000


Integrator Channels Examples
Name: Total Engine Turns
Expr: 'Engine RPM’/60
Minimum result value 0 Maximum: 1500