Using a Time Axis

This article refers to G&L PiC application note document AN000004 and describes how to use a time axis.

1. The time axis can only be used when a STRTSERV funtion is active. 
2. The following functions can be used with a time axis.

               READ_SV           VAR 1   Current position

                                             VAR 6    Current velocity counts/sec                                       

                                             VAR 12  Current rollover position

                                             VAR 26 Axis defined for Synchronized start

               WRITE_SV          VAR 1    Set the poition

                                             VAR 6    Set the velocity in counts/second.               Do not use with SCURVE

                                             VAR 12  Set rollover position

                                             VAR 26 Define Axis for Synchronized start

     With SCURVE additional functions can be used.

               DISTANCE          Move the time axis a distance at defined rate.

               VEL_STRT          Move the time axis at a defined rate

               VEL_END           End the VEL_STRT, DISTANCE, or POSITION move

               POSITION            Position the time axis to a specific count.

               NEWRATE          Change the rate of the VEL_STRT, DISTANCE, or POSITION move

               INPOS?                Check to see if no time axis moves are active.

3. The time axis can be the master axis for all ratio move functions.
4. The time axis cannot be a slave axis.
5. The last move called controls the time axis, there are no ques.
6. If multiple distance moves are called the distances are summed.
7. The time axis will always follow the defined Accel and Jerk when changing speeds if SCURVE is active. 
8. Master start can be used.
9. Registration and Referencing moves cannot be used.
10. The time axis is not declared in SERVO SETUP.
11. When using WRITE_SV (var 6)  the velocity rate is in counts/sec.  When using a DISTANCE, VEL_STRT, or POSITION move the velocity rate is in counts/min.
12. FU = LU, (Feedback units = Ladder units).
13. VEL_END can be used to abort  VEL_STRT, POSITION, and DISTANCE moves.