Delta Data Systems PMAC PCI, Справочник по аппаратуре

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PMAC-PCI Hardware Reference
Mating Connectors 31
This magnitude-and-direction mode is suited for driving servo amplifiers that expect this type of input,
and for driving voltage-to-frequency (V/F) converters, such as PMAC’s Acc-8D Option 2 board, for
running stepper motor drivers.
If you are using PMAC to commutate the motor, you will use two analog output channels for the motor.
Each output may be single-ended or differential, just as for the DC motor. The two channels must be
consecutively numbered, with the lower-numbered channel having an odd number (e.g. you can use
DAC1 and DAC2 for a motor, or DAC3 and DAC4, but not DAC2 and DAC3, or DAC2 and DAC4). For
our motor #1 example, connect DAC1 (pin 43) and DAC2 (pin 45) to the analog inputs of the amplifier. If
using the complements as well, connect DAC1/ (pin 45) and DAC2/ (pin 46) the minus-command inputs;
otherwise leave the complementary signal outputs floating. If you need to limit the range of each signal
to +/- 5V, you will do so with parameter Ix69. Any analog output not used for dedicated servo purposes
may be utilized as a general-purpose analog output. Usually this is done by defining an M-variable to the
digital-to-analog-converter register (suggested M-variable definitions M102, M202, etc.), then writing
values to the M-variable. The analog outputs are intended to drive high-impedance inputs with no
significant current draw. The 220

output resistors will keep the current draw lower than 50 mA in all
cases and prevent damage to the output circuitry, but any current draw above 10 mA can result in
noticeable signal distortion.
Example:
Amplifier Enable Signal (AENAx/DIRn)
Most amplifiers have an enable/disable input that permits complete shutdown of the amplifier regardless
of the voltage of the command signal. PMAC’s AENA line is meant for this purpose. If not using a
direction and magnitude amplifier or voltage-to-frequency converter, you can use this pin to enable and
disable your amplifier (wired to the enable line). AENA1/DIR1 is pin 47. This signal is an open-
collector output with a 3.3 k

pull-up resistor to +V, which is a voltage selected by jumper E100. The
pull-up resistor packs are RP43 for channels 1-4 and RP-56 for motors 5-8. For early tests, you may wish
to have this amplifier signal under manual control.
This signal could be either sinking or sourcing as determined by chips U37 and U53 (see jumpers E100-
E102 and E114-E115). For 24V operation, E100 must connect pins 2-3 and a separate power supply must
be brought on pins 9-7 of the J9 JEQU connector. The polarity of the signal is controlled by jumpers
E17A to E17H. The default is low-true (conducting) enable. The amplifier enable signal could also be
manually controlled setting Ix00=0 and using the suggested definition of the Mx14 variable.