Make an HMI convert from inches to PUUs (numeric input) before writing to servo drive

[ivanbenitezmx]

Hello all,
I'm currently working on a servo motor linear positioning system (ball screw). I'm all set up regarding communication between my HMI and servo drive (RS-232), I can write and read parameters through the HMI to the drive.
Right now I'm setting the positioning command via PUUs, but I want to make the operators life easier by allowing him to input the positioning command in inches. I was thinking on using a macro command that can do this conversion but I'm not really sure how to accomplish this. So my main goal is to input the length to move in inches but make the HMI write the parameter to the servo drive in PUUs.

Any ideas/recommendations would be much appreciated!

System's equipment used:
HMI: Delta-DOP107EG
Servo Drive: ASDA2 0721 M
Servo motor: ECMA-C10807ES
PLC: DVP28SV11R2

 

[parky]

don't know the delta HMI but your post is a little unclear, however, the formula is as below
I do remember using this some time ago, I googled it then & put the formula into the comments of my PLC for reference

//step per inch = (motor steps * microstepping) / (travel at one turn of the motor in inches)
//if microstepping is set at 16 (1/16 on the driver) then and you are using a sprocket and chain with a pitch of .25 inches and 12 teeth on the drive sprocket
//= (200 * 16) / (12 * .25)
//= 3200 / 3
//= 1066.666 steps per inch

//For lead screw that has a travel of .5 inches at one turn like the 5 start 1/2 inch lead screw and using 4 microsteps per step (1/4):
//= (200 * 4) / (.5)
//= 800 / .5
//= 1600 steps per inch