Delta Tau Universal PMAC Lite, Справочник по аппаратуре

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Universal PMAC Lite
Machine Connections 36
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
Ω
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, use this pin to enable and disable
the amplifier (wired to the enable line). AENA1/DIR1 is pin 47. The polarity of the signal is controlled
by jumper E17 and the default is conducting enable.
The amplifier enable signals are controlled by chip U50. If jumper E100 connects pins 1 and 2, U50 will
be supplied from the analog A+15V supply, which can be isolated from the digital circuitry. If E100
connects pins 2 and 3, U50 will be supplied from a separate A+V supply brought in on pin 9 of the J8
JEQU connector. This supply can be in the +12V to +24V range, and can be kept isolated from the
digital circuitry.
By default, the PMAC Lite is provided with a sinking output driver IC (ULN2803A or equivalent) in
U50. In this configuration, jumpers E101 and E102 must connect pins 1 and 2 to supply the IC correctly.
If this IC is replaced with a sourcing output driver IC (UDN2981A or equivalent), E101 and E102 must
be changed to connect pins 2 and 3 to supply the new IC correctly. A wrong setting of these jumpers will
damage the associated output IC.