Data

  

Description

Persistent Numbers are retained through controller power cycles. Persistent information is used to preserve information such as taught locations and cycle counts over the lifetime of a machine. Persistent Numbers retain double precision floating point values. Persistent Numbers are created with the "Add Variable" button in found in the Data Category and checking the "Persistent" checkbox.

Escapes

Reading the value of a Persistent Number does not generate any escapes

Examples

This block list performs a transfer operation using taught persistent numbers for pickup and placement locations:

If information is retained in Persistent Numbers it is a good idea to save those values in a file so that if the controller is field replaced the persistent values could be restored into the replacment controller. This list of blocks saves some persistent variables to a file:

This is a simple homing procedure that concludes by setting the actual position:

This alternative procedure avoids use of the abrupt abort command and is just as accurate:

Although accurately homed a position display would show that the axis is not at 0 but at a number which corresponds to the decel distance after the sensor edge was found. Seeing the position after homing not be "0" is for some applications unexpected. If that is a concern the motor can be moved back to zero:

There are additional considerations for homing. Review the Homing topic to see what pertains to the current application.