Modifying Motion ON-THE-FLY

[tonomar]

Hello

How can I modify the motion (acceleration, velocity) on the fly using PCI 7344.

Some thing like this:

http://www.motioneng.com/trajectory_mod.html

Thank you

[Jochen]

Hi,

there are several ways to accomplish this:

1. Load new values for acceleration and velocity while your motor is moving. To commit these values call the flex_start() command again. The axis will accelerate/decelerate to the new velocity immediately. The move doesn't get interrupted by these commands.
   
   
2. If you don't need to vary the acceleration you could also use the flex_load_velocity_override() function. This function allows you to scale the velocity that you have loaded previously between 0 and 100 %. When you call this function, the velocity of an ongoing move changes with the previously loaded accel/decel values.

Method one is a bit more flexible as it allows you to adjust all move constraints on the fly, while the second method executes much faster (lower execution delay).
I have provided the C function names. If you are using LabVIEW you will find VIs with very similar names.

I hope this helps,

Jochen Klier
National Instruments Germany

[TulioB]

Those methods apply on contour mode movements?

[Jochen]

Hi Tulio,

no. As trajectory generation works differently in contour mode, you can't apply those methods to contour mode.
The best way to do something similar in contour mode is to download only small chunks of position data to the contouring buffer in a loop. This allows you to modify your contouring data on the fly but with some amount of delay.

Jochen