Delta Tau Geo MACRO, User Manual And Reference Manual

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Geo MACRO Drive User Manual
104 Setting Up Discrete Inputs and Outputs
MS0,MI926=1010 ; Set back end compare in B
MS0,MI923=0 ; No auto-increment
MS0,MI929=0 ; Prepare initial value of 0
MS0,MI928=1 ; Enable direct write (resets immediately to zero)
{Command to start the move}
Setting up for Multiple Pulse Outputs
By using the auto-increment feature, it is possible to create multiple compare pulses with a single software setup
operation. When the auto-increment register is a non-zero value, its value is added to or subtracted from one
compare register’s value automatically when the other compare value is matched. PMAC keeps track of the
direction of incrementing, so only positive values should be used in the auto-increment register, even if the
encoder will be counting in the negative direction.
The setup for multiple pulses is like the setup for a single pulse, except that a non-zero value must be entered
into the auto-increment register and the value entered for the back edge must be that of the first back edge minus
the auto-increment if the move will be positive or that of the first back edge plus the auto-increment value if the
move will be negative.
In other words, the starting values to the two compare registers must “bracket” the starting position. When either
compare value is matched by the encoder counter, the other compare value is incremented in the direction of
movement.
Starting Position
B
0
A
0
B
1
A
1
Auto-Increment
Example: Starting with the above example, the compare output should be between 1000 (A
0
) and 1010 (B
1
)
counts, but add an auto-increment value of 2000 counts with a starting position of about 100 counts. The
program code to start the sequence could be:
MS0,MI925=2000 ; Auto-increment of 2000 encoder counts
MS0,MI926=1000 ; First front edge (A0) at 1000 counts
MS0,MI923=(1010-1000) ;[1010-MS0,MI926]First back edge (B1) at 1010 counts
MS0,MI929=0 ; Prepare initial value of 0
MS0,MI928=1 ; Enable direct write (resets immediately to zero)