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PMAC 2 Software Reference

156 PMAC I-Variable Specifiation

Specifically, I998 controls how many times the SERVO clock frequency is divided down

from the PHASE clock, whose frequency is set by I992 and I997. The SERVO clock

frequency is equal to the PHASE clock frequency divided by (I998+1). I998 has a range

of 0 to 15, so the frequency division can be by a factor of 1 to 16. The equation for I998

is:

)kHz(ServoFreq

)kHz(PhaseFreq

998I −=

The ratio of PHASE Clock Freq. to SERVO Clock Freq. must be an integer.

Note:

If jumper E1 is ON, PMAC2 Ultralite gets its SERVO clock signal

externally from a serial-port input, and I998 is not used.

For execution of trajectories at the proper speed, I10 must be set properly to tell the

trajectory generation software what the SERVO clock cycle time is. The formula for I10

is:

)kHz(ServoFreq

608,388,8

10I =

In terms of the variables that determine the SERVO clock frequency on a PMAC2 Ultralite

board, the formula for I10 is:

()()()

1998I1997I3992I*2

640

10I +++=

Example

With a 6.67 kHz PHASE Clock frequency established by I900 and I997, and a desired 3.33

kHz SERVO Clock frequency:

I998 = (6.67 / 3.33) - 1 = 2 - 1 = 1

I999 (Reserved for Future Use)

MACRO Software Setup I-Variables

I1000 MACRO Node Auxiliary Register Enable

Range

0 .. $FFFF (0 .. 65,535)

Units

none

Default

Remarks

This parameter controls which MACRO nodes PMAC performs automatic copying into

and out of the auxiliary registers. Enabling this function for a node is required to use the

auxiliary register as the flag register for a motor.

I1000 is a 16-bit variable. Bits 0 to 15 control the enabling of this copying function for

MACRO nodes 0 to 15, respectively. A bit value of 1 means the copying function is

enabled; a bit value of 0 means the copying function is disabled.

If the copying function is enabled for Node n (where n = 0 to F hex or 0 to 15 decimal),

during each background “housekeeping” software cycle, PMAC copies the contents of

Y:$0F7n to the Node n auxiliary write register, and copies the contents of the Node n

auxiliary read register into X:$0F7n.

The copying function enabled by I1000 permits PLC and on-line-command auxiliary read

and write functions plus use of the auxiliary registers for command and status flags.