Delta Data Systems PMAC PCI, Справочник по аппаратуре

Страница: 45 / 80

PMAC-PCI Hardware Reference
Mating Connectors 35
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 provide 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 $FFC1. 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 PMAC1 PCI. 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.
In firmware versions 1.17C and below only Option 12 (ADC’s 1-8) was functional using setup variables
I60 and I61 for automatic data conversion. The I60 and I61 method of automatic data conversion can still
be used on 1.17D and above but the Option 12A (ADC’s 9-16) will not function. Two properly setup all
16 ADC’s on the PMAC1 PCI when option 12 and option 12A are ordered, the user must be using
firmware version 1.17D (and above) and use the setup methods that follow.
Hardware Characteristics
The analog inputs can be used as unipolar inputs in the 0V to +5V range, or bipolar inputs in the -2.5V to
+2.5V range. Each input has a 470

input resistor in-line, and a 0.033

F resistor to ground. This
provides a 16

sec time constant on each input line.
The analog-to-digital converters on PMAC1 PCI r5V and -12V supplies. These supplies are not
isolated from d5V circuitry on PMAC If the PMAC1 PCI is plugged into the bus (PC or VME),
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 ma12V supply voltages are available on the JANA connector to supply the analog
circuitry providing the signals. The +12V supply is not used by PMAC1 PCI; it is merely passed through
to the JANA connector for convenience. If use of this supply is desired, it must either come from the bus
supply through PMAC1 PCI’s bus connector, or from TB1.
Multiplexing Principle
Only one pair of analog-to-digital converter registers is available to the PMAC1 PCI processor at any
given time. The data appears to the processor at address Y:$FFC8. The data from the selected analog
input 0 to 7 (ANAI00-ANAI07) appears in the low 12 bits; the data from the selected analog input 8 to 15
(ANAI08-ANAI15) appears in the high 12 bits (this data is only present if Option 12A has been ordered).