Technical FAQs

# I need help understanding scaling in Lexium 32

Understanding scaling can be a little tricky for first time users of Lexium 32.

The usr_a and usr_p refer to the factory units for acceleration and position respectively.

The factory scaling for positioning is based on 16384 increments per revolution of the motor shaft.
16384 increments = 1 motor shaft revolution

Position scaling can be can be changed to meet your system needs

The factory scaling for acceleration is a change in acceleration based on the selected target velocity of 1 motor shaft revolution per minute per second.

Acceleration scaling can also be changed but you should use the same units of measure as the units you choose for position scaling.
Note, this is also true for velocity scaling.

When you are connected to the drive with SoMove the icon for "Graphical Representation" will be available.
Clicking on this icon will open up the scaling window which allows you to change the units of measure to meet your needs.

For example:   If the motor was directly driving a Schneider Electric linear motion products such as a PAS43.
The Schneider Electric linear axis PAS has a pulley diameter that equals 205mm of linear travel for 1 rotation of the pulley (one rotation of the motor shaft)
In this instance we have set the position scaling to mm and the acceleration and velocity are also based on mm

When we want our linear motion to move 1 mm, we simply enter "1" as our position value and the scaling is handled within the drive.
The motor turns the requires distance to move the linear motion 1mm
This way we do not have to send a position value of 79.92xxxxxxx to move a distance of 1 mm
16384 / 205 = 79.921951xxxxxxxx     or 79.921xxxx for each mm of travel

Scaling makes life easier when mechanical motion is involved and we want to work with "real" values.

Setting the scaling as seen below in attached image 1.

Turn on the drive and set the home position to zero and then tell the drive to move to 410mm.  The motor shaft moves exactly 2 full rotations.  Therefore if we were actually using a linear slide PAS43, we can use "real" numbers for our position commands as compared to working in motor increments per revolution.  "16384"

If we wanted more resolution we would have simply chosen um as our units instead of mm and set our position scaling at 205000

This should help you to understand how to use scaling in Lexium 32 to simplify your applications.