VXI VT1422A, User Manual

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120 Programming the VT1422A for Data Acquisition and Control Chapter 4
Setting Output
Drive Type
The VT1533A and VT1534A use output drivers that can be configured as
either active or passive pull-up. To configure this, use the command
OUTPut:TYPE <
mode >,(@< ch_list >). This setting is valid even while the
specified channel in not an output channel. If and when the channel is configured
for output (an output FUNCtion command), the setting will be in effect.
•
The < mode > parameter can be either ACTive or PASSive. When set
to ACT (the default), the output provides active pull-up. When set to
PASS, the output is pulled up by a resistor.
•
The < ch_list > parameter specifies the channels to configure.
The VT1533A has two channels of 8 bits each. All 8 bits in a channel
take on the configuration specified for the channel. The VT1534A has
8 I/O bits that are individually configured as channels.
To configure the higher 8-bit channel of a VT1533A for passive pull-up:
OUTP:TYPE PASS,(@109)
SCP in SCP position 1
To configure the upper 4 bits of a VT1534A for active pull-up:
OUTP:TYPE ACT,(@132:135)
SCP in SCP position 4
Setting Output Functions
The VT1533A Digital I/O SCP, VT1534A, and VT1538A Frequency/
Totalizer SCPs can output static digital states. The Frequency/Totalizer
SCPs can also output single pulses per trigger, continuous pluses that are
width modulated (PWM) and continuous pulses that are frequency
modulated (FM).
Static State (CONDition) Function
To configure digital channels to output static states, use the
SOURce:FUNCtion:CONDition (@<
ch_list >) command. Examples:
To set the upper 8-bit channel of a VT1533A in SCP position 4 to output
SOUR:FUNC:COND (@133)
To set the lower 4 channels (bits) of a VT1534A in SCP pos 2 to output states
SOUR:FUNC:COND (@116:119)
Variable Width Pulse Per Trigger
This function sets up one or more VT1534A or VT1538A channels to output
a single pulse per trigger (per algorithm execution). The width of the pulse
from these channels is controlled by Algorithm Language statements.
Use the command SOURce:FUNCtion[:SHAPe]:PULSe (@<
ch_list >).
Example command sequence:
To set VT1534A/38 channel 2 at SCP position 4 to output a pulse per trigger
SOUR:FUNC:PULSE (@134)
Example algorithm statement to control pulse width to 1 ms
O134 = 0.001;