PMAC Product Guide Ix90 C.S. x Feedrate Time Units : This parameter determines the units of time used for either the Ix89 I- variable or the F motion program parameter in compare to milliseconds. The default value of 1000 defines the federate in units per second. Encoder/Flag Setup I-Variables I900, I905,.. Encoder 0 Decode Control : This variable determines how an increase in the encoder feedback counter will be interpreted when translated into position. An increase in the encoder counter can be interpreted as an increase or a decrease in the position counter, thus determining the proper direction of motion.
Typical values are either 3 or 7 which respectively determine a clock-wise or counter-clockwise direction of decoding. I902, I907,.. Encoder 0 Capture Control : This variable determines the trigger condition that results in the completion of the home search command. For example, the trigger condition could be a combination of the home sensor being activated and the encoder C channel rising high. I903, I908,.. Encoder 0 Flag Select : This variable determines which flag will be used for the home trigger condition, selected from the home flag, the end-of-travel limits or the amplifier fault flag. Note:
The EZ-PMAC Setup Software has a dedicate screen for the configuration of the homing I-Variables. Encoder Conversion Table The PMAC Encoder Conversion table is a method to adapt the different kind of feedback information into a standard format that PMAC can use for its servo calculations. For example, the information provided by a regular quadrature encoder might be different than that of a parallel feedback sensor. However, the feedback information provided by these two different sensors would have the same format after the encoder conversion table processes it. For most PMAC users with quadrature encoders, this process can be virtually transparent with no need to worry about the details.
To set the encoder conversion table for using regular quadrature encoders for motors 1-4, enter these commands on the terminal window: WY:$720,$00C000 WY:$721,$00C004 WY:$722,$00C008 WY:$723,$00C00C WY:$724,$000000 Jogging Moves Jog Acceleration Jog/home acceleration time is specified by Ix20 for motor x, and the S-curve time by Ix21. If Ix20 is less than two times Ix21, the acceleration time used will be twice Ix21. The acceleration limit for jog/home moves is set by Ix19 (in counts/msec 2 ). If Ix20 and Ix21 are so small that Ix19 would be exceeded, Ix19 controls the acceleration time (without changing the profile shape).
To specify the acceleration by rate instead of time, simply set the acceleration time parameters small enough that the limiting acceleration rate parameter is always used. To specify the acceleration by rate, do not set both acceleration time parameters Ix20 and Ix21 to zero. This will cause a division-by-zero error in the move calculations that could cause erratic movement. The minimum acceleration time setting should be Ix20=1 and Ix21=0. Programming PMAC 55