User's Manual

PMAC User Manual
10 Getting Started with PMAC
There are many combinations of amplifier types, motor types and feedback device types that can be
connected to PMAC, each requiring a somewhat different procedure. The easiest connection is that of a
DC motor and amplifier with an incremental encoder. That is what is described first here. Other options
will be discussed later, or in other sections.
Typically, connections are made to a terminal block that is attached to the JMACH connector by a flat
cable (Acc- 8D or 8P). The pinout numbers on the terminal block are the same as those on the JMACH
connector for PMAC PC. Make sure PMAC is un-powered while the connections are being made. Leave
any loads disconnected from the motor at this point.
Machine Connectors
The primary machine interface connector is JMACH1 (J8 on PMAC PC, J11 on PMAC Lite, P2 on PMAC
VME, J4 on PMAC STD top board). It contains the pins for four channels of machine I/O: analog outputs,
incremental encoder inputs, and associated input and output flags, plus power-supply connections. These
four channels can be used for two to four motors, depending on the configuration. Our example will use
this connector.
The next machine interface connector is JMACH2 (J7 on PMAC PC, P2A on PMAC VME, J4 on the
middle board of an 8-channel PMAC STD, not available on a PMAC Lite). It is essentially identical to the
JMACH1 connector for two to four more axes. It is present only if the PMAC card has been fully
populated to handle eight axes (Option 1), because it interfaces the optional extra components.
Note:
While the numbering scheme for the pins on machine connectors on PMAC VME is
different from that for PMAC PC, the physical arrangement is the same, and PMAC
VME can use the same terminal numbers on the terminal block board.
Connecting the Analog Power Supply
The analog output circuitry on PMAC is optically isolated from the digital computation circuitry, and so
requires a separate power supply. This is brought in on the JMACH connector. The positive supply (+12
to +15 volts) should be brought in on the A+15V line on pin 59. The negative supply (-12 to -15V) should
be brought in on the A-15V line on pin 60. The analog common should be brought in on the AGND line on
pin 58.
Typically, this supply can come from the servo amplifier. Many commercial amplifiers provide such a
supply. If this is not the case, an external supply may be used. Even with an external supply, the AGND
line should be tied to the amplifier common.
As mentioned before, it is possible to get the power for the analog circuits from the bus, but doing so
defeats optical isolation. In this case, no new connections need to be made. However, be sure jumpers
E85, E87, E88, E89, and E90 are set up for this circumstance as explained previously in the Preparing the
Card section. (The card is not shipped from the factory in this configuration.)
Incremental Encoder Connection
Each JMACH connector provides two +5V outputs and two logic grounds for powering encoders and other
devices. The +5V outputs are on pins 1 and 2; the grounds are on pins 3 and 4. The encoder signal pins are
grouped by number: all those numbered 1 (CHA1, CHA1/, CHB1, CHC1, etc.) belong to encoder #1. The
encoder number does not have to match the motor number, but usually does. If the PMAC is not plugged
into a bus and drawing its +5V and GND from the bus, use these pins to bring in +5V and GND from the
power supply.