MOVEABSSEQSP type problem

MOVEABSSEQSP type problem

Work out how many points per second are being executed in the MOVEABSSEQSP.  If more than one per msec then that is not possible even with the MOVEABSSEQ type move.  The other consideration is the vector length in the buffer.  The LIMIT_BUFFERED value 64 is there to allow the system to calculate the deceleration position given the total vector length in the buffer.  The vector length (VECTOR_BUFFERED) must be greater than SPEED ^ 2 / (2 * DECEL)

Equation of motion used: v^2 = u^2 + 2*a*s
for decel distance, the u is 0
so v^2 = 2*a*s

s is the distance, so s = v^2 / 2 * a

v is SPEED, a is DECEL so minimum vector length for smooth movement is SPEED ^ 2 / (2 * DECEL)

Normally 64 moves in the buffer is enough.  You do not need to buffer 100 or 200 or 500 moves, the MOVEABSSEQSP will keep adding a new move to the buffer and the vector length will be maintained above the required value.

You can scope VECTOR_BUFFERED, VP_SPEED and MOVES_BUFFERED to see if buffer starvation is the problem or not.

    • Related Articles

    • Inconsistent speed

      The max speed of the axis might be acceleration limited. For example: SPEED = 800 ACCEL = 1200 DECEL = 1200 Say the vector length = 600 - 500 = 100. ie the MOVE length is 100. From the standard equation of motion: v^2 = u^2 + 2as u is 0 v = SQR(2 * ...

    • MOVEABS not ending in Target positon

      The cause the problem is that a MOVEABS takes ENDMOVE of the previous move as the start point. When we cancel the move in the MTYPE, it stops before ENDMOVE so it is not a valid start point any more. Here is a possible solution but it is not perfect. ...

    • 'Forward' speed change during move

      FORWARD commands do not need to buffer. Just set FORWARD once and leave it running. You can change SPEED any time on the fly. SPEED set to 0 will stop the axis. A negative SPEED value will make the axis move in reverse. You only need to CANCEL when ...

    • XYZ axes running slower than expected

      One of our customers faced a problem with Slow Speed on all Axes.  They just changed the Y axis Drives with a different type and changed the UNITS (higher) which seems good becasue they can move the Axis more precisely.  But now when running XYZ ...

    • MOVEABS and MOVABSSEQ AN-273

      The MOVEABSSEQ and MOVESEQ commands allow a sequence of 2 to 6 axis movements to be loaded via TABLE values. The moves can be automatically blended together using a circular or spherical arcs. The sequence of points is loaded as a sequence of MOVEABS ...