Measurement Computing PCIM-DAS1602/16 - Manual (Page 14)

PCIM-DAS1602/16 User's Guide Installing the PCIM-DAS1602/16
DAC0 and DAC1 Range Select jumper (D/A Converter Reference)
The PCIM-DAS1602/16 has an on-board precision voltage reference at jumper P7 that you can use to select the
output ranges of the digital to analog converters. Both of the board's D/A outputs are factory-configured with a
range of
−5 to +5 volts ( .) Figure 2-5
Figure 2-5. D/A0 and D/A1 Range jumper
Figure 2-5
Analog output is provided by two 12-bit multiplying D/A converters (DAC1 and DAC). This type of converter
accepts an input reference voltage, and provides an output voltage which is both inverse to the reference voltage
and proportional to the digital value in the output register. The proportion is controlled by the D/A output code
(0 to 4095). Each bit represents 1/4096 of full scale. For example, in unipolar mode, the supplied reference of
−5 V provides a +5V output (actually 4.9988 V) when the value in the output register is 4095 (full scale at 12
bits of resolution). It provides a value of 2.5 V when the value in the output register is 2048.
A precision −5 V and −10 V reference provides onboard D/A ranges of 0 to 5 V, 0 to 10 V, ±5 V, ±10 V. Other
ranges between 0V and 10V are available when you provide a precision voltage reference at pin 10 (D/A0) or
pin 26 (D/A1) of the board's main connector.
Bipolar/Unipolar Select jumpers
Code Function (default jumpers shown)
5
10
SH
User supplied D/A reference U
5 Volt Range
10 Volt Range
Sample & Hold Trigger
1 S 1
0 H 0 5 U U 5
D/A0 and D/A1 Range jumper block
B
U
DAC1
B
U
DAC0
P6 P5
Simultaneous sample and hold (SSH) trigger
When the DAC1 reference is supplied on-board, pin 26 of the 37-pin connector is unused ( ). You can
enable this pin as a SSH (simultaneous sample & hold) trigger for use with the CIO-SSH16 board. To configure
this, place the jumper between the two pins labeled SH, as shown in
.
Figure 2-7
Clock Select jumper
Jumper P2 configures the frequency of the square wave used as a clock by the A/D pacer circuitry. This pacer
circuitry controls the sample timing of the A/D.
You can configure the frequency for 10 MHz or 1 MHz. The Clock Select jumper is factory-configured for 1
MHz, as shown in
. Figure 2-6
2-5