FASTER.CLOCK V01 RP AUTOMATION INC 11JAN89

DESCRIPTION

The programs in this file allow the VAL-II system clock to

be changed to interrupt the system faster than the standard

VAL-II operating system expects. This feature must be used

with extreme caution because VAL-generated motions WILL BE

AFFECTED BY THIS CHANGE.

PREPARATION

Load in the FASTER.CLOCK file from the floppy diskette.

PROGRAM EXECUTION

Execute the FASTER.CLOCK program, and the different clock

settings that can be obtained through this program will be

displayed on the CRT screen. After selecting one of the six

values, the program will proceed to make the desired change.

The clock rate values range from a high of 28.8 milliseconds

(normal VAL-II rate) down to 4.8 milliseconds.

NOTES

With any clock rate below 10 milliseconds, the Teach Pendant

will not work in the system. Actually, it will prevent arm

power from turning (or staying) on. So, the Teach Pendant

must be disconnected before selecting a clock rate below 10

milliseconds.

Any changes in the clock rate will cause all motions to act

differently. This is because the VAL-II system still thinks

that the clock rate is 28.8 milliseconds, but it is not. The

system plans the motions so that they will take a certain

number of clock ticks. When the clock speeds up, the motions

also get faster. This will happen until the arm gets some

kind of a SERVO ERROR (usually ENVELOPE or HIGH ACCELERATION

error).

Straight-line motions probably cannot be done with any clock

rates less than 20 milliseconds. This is because the VAL-II

calculations must be finished within a certain timeframe and

this amount of time may not be enough.

MESSAGE

*** ILLEGAL SELECTION ***

If an answer which is not 1-6 is given when selecting the

new clock rate, then this message gets displayed, and the

selection is made again.