Chapter 5
Calibration
©
National Instruments Corporation
5-15
When calibrating an E-series board for either unipolar or bipolar analog
output or input, make sure that all calibration constants for that particular
mode are loaded. For example, if you want to calibrate the PCI-6031E for
bipolar analog output, be sure to load the constants stored in EEPROM
memory location 414, 415, 416 and 417 into the MB88341 CALDAC.
The Serial Command Register has five bits—SerClk (bit 0), SerData (bit 1),
SerDacLd0 (bit 3), SerDacLd1 (bit 4), and SerDacLd2 (bit 5)—that are
connected to the serial DAC clock, data in, load for the CALDAC.
The format for writing to all of the serial DACs is similar to the EEPROM.
The basic write cycle consists of shifting an address/data pair into the DAC,
then pulsing the appropriate SerDacLd pin. The timing diagram for the
write cycle for each DAC is shown in Figure 5-2 (a, b, c, d).
The serial DAC interface is relatively slow compared to the PCI bus. In
order to meet the timing specifications of the serial DAC, you must double
write the clock bit. In other words, when setting the clock bit low, you must
write 0 twice, and when setting it high, you must write 1 twice.
Note
Review the timing diagram and specifications very carefully before attempting to
write code.
PCI-6023E
✓
—
—
—
PCI-6024E
✓
—
—
—
PCI-6025E
✓
—
—
—
PCI-6031E
—
✓
✓
✓
PCI-6032E
—
✓
✓
✓
PCI-6033E
—
✓
✓
✓
PCI-6052E
3
✓
—
—
✓
1
When writing to this CALDAC an address is not necessary.
2
Used for analog triggering.
3
This board uses two MB88341 CALDACs.
Table 5-7.
Type of CALDAC Used on Board (Continued)