User's Manual

PMAC User Manual
Getting Started with PMAC 13
Encoder I-Variables
Several I-variables are linked to particular encoder inputs, regardless of which motor the encoder is
assigned to. These control how the encoder signal is interpreted. They are numbered in the 900s: I900-
I904 belong to Encoder 1, I905-I909 belong to Encoder 2, and so on, to I975-I979 belonging to Encoder
16. Initially we will only concern ourselves with the first encoder I-variable.
I900, I905, I910, Etc.
These control the decoding of the encoder signal into counts. Quadrature x1, x2, and x4, plus pulse and
direction decode, are all possible. PMAC is shipped with counterclockwise x4 decode set up (I900, I905,
... = 7). Check this value for Encoder 1 (I900), and change it to 7, if it is different.
I901, I906, I911, etc.
Encoder digital filter disable – This controls whether the digital delay filter for noise spike elimination is
turned on. PMAC is shipped with the filters on (I901, I906, ... = 0).
I902, I907, I912, etc.
Encoder position capture control – This controls which transitions of those associated encoder signals
trigger a position capture for that encoder. This must be used for homing moves. It can also be used for
other purposes. It specifies an edge of the encoder third channel, the edge of one of the encoder flags, or
the edge of a logically combined signal from both. If it uses a flag, also set the next variable. The default
value for this variable is 1 specifying the rising edge of the third channel.
I903, I908, I913, etc.
Encoder flag select control – This controls which of the encoder flags is used to trigger a position capture
if the previous I-variable has specified that a flag be to be used. Usually, this is set to 0 to specify the home
flag (HMFLn).
Motor I-Variables
PMAC can be attached to up to eight motors, called 1 to 8. A motor is defined in PMAC by setting up I-
variables that tell the I/O addresses of the input and output data (where to look for the feedback position,
and where to send the output command).
The I-variables for motor 1 are in the 100s (I100-I184); for motor 2 in the 200s, and so on, to the 800s for
motor 8. As a shorthand to refer to a particular variable independent of a particular motor, the hundreds
digit is replaced with the letter x. For instance, Ix20 refers to I120 for motor 1, or I220 for motor 2, and so
on.
In this example, set up motor 1. In preparation, disable motor 1 by cutting power to the amplifier.
Motor Activation
The first thing to do in the software setup of a motor is to activate the software algorithms for the motor by
setting Ix00 to 1. For Motor #1, set I100 to 1.
For PMAC-Commutated Motors Only
If using PMAC to commutate this motor, set up the commutation algorithm I-variables at this point. First,
set I101 to 1 to tell PMAC that motor 1 is to be commutated by PMAC.
Analog Outputs
Tell PMAC which pair of analog outputs are being used to command the amplifier. Do this by setting Ix02
to the lower address of the pair of outputs that have been wired to the amplifier. To tell motor 1 to use
DAC1 and DAC2 in the example, set I102 to $C002 (49154).