Reference Manual

PMAC 2 Software Reference

PMAC I-Variable Specification 61

Ix05 Motor x Master (Handwheel) Position Address

Range

Legal PMAC X addresses

Units

Legal PMAC X addresses

Default

$073F (1855) (= zero register at end of conversion table)

Remarks

Ix05 tells the PMAC where to look for the position of the master, or handwheel, encoder

for Motor x. Usually this is an entry in the Encoder Conversion Table that holds processed

information from an encoder channel. The instructions for setting this parameter are

identical to those for Ix03, except the extended bits mean different things. The default

value permits handwheel input from the JPAN connector (jumpered into the ENC2 counter

with E22 and E23).

Following

Modes: The source address of the position information occupies bits 0 to 15 of

Ix05 (range $0000 to $FFFF, or 0 to 65535). With bit 16 equal to zero – the normal case –

position following is done with the actual position reported for the motor reflecting the

change due to the following. With bit 16 – value 65536 – equal to one, the actual position

reported for the motor does not reflect the change due to the following (“offset” mode).

This mode can be useful for part offsets, and for superimposing programmed and

following moves. For example, to have motor #1 following encoder 2 in offset mode, I105

should be set to $10721.

Note:

In the extended version, it is easier to specify this parameter in

hexadecimal form. With I9 at 2 or 3, the value of this variable will

be reported back to the host in hexadecimal form.

Note:

It is important not to have the same source be both the master and

the feedback for an individual motor. If this is the case, with

Ix06=1 to enable following, the motor will run away (it is like a

puppy chasing its tail – it cannot catch up to its desired position,

because its desired position keeps moving ahead of it).

If you want to ensure that following cannot occur by accident, you may want to change

Ix05 so it points to a register that cannot change. This way, even if the following function

gets turned on, for instance by the motor selector inputs on the JPAN connector, no

following can occur. The best registers to use for this purpose are the unused ones at the

end of the conversion table. With the default table setup, you can choose any register

between $072A and $073F (1834 to 1855 decimal). If you extend the table, choose a