User's Manual

PMAC User Manual
Getting Started with PMAC 7
If using single-ended encoders, have the jumpers set up for non-differential. If using differential encoders
with open-collector drivers on each channel (this is rare), have the jumpers set up for differential (pins 2
and 3 connected, providing an effective 500 ohm pull-up on the complementary line). If using encoders
with differential line drivers, the jumpers can be set either way, although it is preferable to have them set
for differential to balance the lines.
Note:
If not using a certain encoder input, it is better to leave it jumpered for single-ended
input; otherwise it is much more likely to pick up extraneous noise as count
information.
Analog Circuit Jumpers
On PMAC, the analog output circuitry can be optically isolated from the digital logic circuitry for noise
reduction purposes. PMAC is shipped from the factory with the circuits optically isolated (E85, E87, and
E88 OFF). It is recommended that the card be used in this configuration, but it is possible to jumper the
bus supply voltage (+/- 12V) over to the analog circuitry by putting these jumpers ON, defeating the optical
isolation, but eliminating the need for an separate power source.
Isolated Setup
With the optical isolation in effect, it is necessary to provide separate power supply to the analog output
circuitry. On the JMACH connectors, the A+15V analog supply should be brought in on pin 59, the A-15V
analog supply on pin 60, and the analog ground (AGND) on pin 58. (Jumper E89 should be ON, and
Jumper E90 should connect Pins 1 and 2 to permit this +15V to pull up the limit-switch and other optically
isolated inputs, which is required for PMAC to command motion. PMAC is shipped with E89 and E90 in
this configuration.) Most amplifiers provide supply outputs for this purpose. Alternatively, an external
supply may be used.
Non-Isolated Setup
The +12V and -12V bus supplies may be used to power the analog output circuitry by jumpering them
across to the analog side with E85 (+12V), E87 (Analog GND), and E88 (-12V); however, this defeats the
isolation and connects the whole computer electrically to the amplifier. This is not recommended and
should only be done for low power systems. To power the flags from the bus +12V supply as well, Jumper
E90 must be moved to connect Pins 2 and 3, so the +12V can pull up the limit-switch and other optically
isolated inputs.
Re-initialization Jumper
If the card powers up or resets with jumper E51 in its default state (OFF for PMAC PC, Lite, and VME;
ON for PMAC STD), PMAC will go through its normal reset cycle, utilizing the setup parameters (such as
I-variables that were previously saved in EAROM.
Standard and Option 5 PMACs
If a PMAC with the Standard or Option 5 CPU powers up or resets with E51 in the non-default state (ON
for PMAC PC, Lite, and VME; OFF for PMAC STD), PMAC will re-initialize as it resets, utilizing the
factory default parameters. Usually, this setting will be used only if the card software and parameters are
so confused that even basic communications is impossible. For startup, make sure this jumper is in its
default state.