User's Manual

Turbo PMAC PCI Lite
16 Machine Connections
Frequency Decode
When used in this fashion, Encoder 4 must be set up for pulse-and-direction decode by setting I915 to 0
or 4. Usually, a value of 4 is used because with CHB4 (direction) unconnected, a positive voltage causes
the counter to count up. The encoder conversion table can then take the difference in the counter each
servo cycle and scale it, providing a value proportional to frequency, and therefore to the input voltage.
Usually this is used for feedrate override (time base control), but the resulting value can be used for any
purpose.
Power Supply
For the V/F converter to work, PMAC must have +/-12V supply referenced to digital ground. If PMAC
is in a bus configuration, usually this comes through the bus connector from the bus power supply. In a
standalone configuration, this supply must still be brought through the bus connector (or the supply
terminal block), or it must be jumpered over from the analog side with E85, E87, and E88, defeating the
optical isolation on the board.
Thumbwheel Multiplexer Port (JTHW Port)
The Thumbwheel Multiplexer Port, or Multiplexer Port, on the JTHW (J3) connector has eight input lines
and eight output lines. The output lines can be used to multiplex large numbers of inputs and outputs on
the port, and Delta Tau provides accessory boards and software structures (special M-variable definitions)
to capitalize on this feature. Up to 32 of the multiplexed I/O boards may be daisy-chained on the port, in
any combination.
The Acc-18 Thumbwheel Multiplexer board provides up to 16 BCD thumbwheel digits or 64 discrete
TTL inputs per board. The TWD and TWB forms of M-variables are used for this board.
The Acc-34x family Serial I/O Multiplexer boards provides 64 I/O point per board, optically isolated
from PMAC. The TWS form of M-variables is used for these boards.
The Acc-8D Option 7 Resolver-to-Digital Converter board provides up to four resolver channels
whose absolute positions can be read through the thumbwheel port. The TWR form of M-variables is
used for this board.
The Acc-8D Option 9 Yaskawa
TM
Absolute Encoder Interface board can connect to up to four of
these encoders. The absolute position is read serially through the multiplexer port on power up.
If none of these accessory boards is used, the inputs and outputs on this port may be used as discrete, non-
multiplexed I/O. They map into PMAC’s processor space at Y address $78801. The suggested M-
variable definitions for this use are M40 to M47 for the eight outputs, and M50 to M57 for the eight
inputs. The Acc-27 Optically Isolated I/O board buffers the I/O in this non-multiplexed form with each
point rated to 24V and 100 mA.
Optional Analog Inputs (JANA Port)
The JANA port is present only if Option 12 is ordered for the PMAC. Option 12 provides eight 12-bit
analog inputs (ANAI00-ANAI07). Option 12A provides eight additional 12-bit analog inputs (ANA08-
ANAI15) for a total of 16 inputs. The analog inputs can be used as unipolar inputs in the 0V to +5V
range, or bi-polar inputs in the -2.5V to +2.5V range.
The analog-to-digital converters on PMAC require +5V and -12V supplies. These supplies are not
isolated from digital +5V circuitry on PMAC. If the PMAC is plugged into the PCI bus, these supplies
are taken from the bus power supply. In a standalone application, these supplies must be brought in on
terminal block TB1. The -12V and matching +12V supply voltages are available on the J30 connector to
supply the analog circuitry providing the signals.