User`s guide

Universal Library User's Guide Analog Input Boards - USB-1408 Series
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*Although cbCIn() and CIn() are valid for use with this counter, cbCIn32() or
CIn32() may be more appropriate, since the values returned may be greater than
the data types used by cbCIn() and CIn() can handle.
**cbCLoad(), cbCLoad32(), CLoad() and CLoad32() only accept Count=0. These
functions are used to reset the counter.
Counter I/O argument values
CounterNum 1
Count 2
32
-1 when reading the counter.
0 when loading the counter.
cbCLoad() and cbCLoad32() / CLoad() and CLoad32()are only used to reset the
counter for this board to 0. No other values are valid.
The ―Basic signed integers‖ guidelines on page 140 apply when using cbCIn() or
CIn() for values greater than 32767, and when using cbCIn32() or CIn32() for
values greater than 2147483647.
RegNum LOADREG1
Event notification
Event notification functions and methods supported
UL: cbEnableEvent(), cbDisableEvent()
UL for .NET: EnableEvent(), DisableEvent()
Event types: ON_SCAN_ERROR (analog input), ON_DATA_AVAILABLE, ON_END_OF_AI_SCAN,
ON_END_OF_AO_SCAN and ON_SCAN_ERROR (analog output)
Hardware considerations
Acquisition Rate
Since the maximum data acquisition rate depends on the system connected to the USB-1408FS, it is possible
to "lose" data points when scanning at higher rates. The Universal Library cannot always detect this data loss.
Maximum rates may be lower in Windows operating systems that predate Windows XP. Most systems can
sustain rates of 40 kS/s aggregate in BLOCKIO mode, and 1 kS/s aggregate in SINGLEIO mode.
EXTCLOCK
By default, the SYNC pin is configured for pacer output and provides the internal pacer A/D clock signal. To
configure the pin for pacer input, use the EXTCLOCK option.
If you use the EXTCLOCK option, make sure that you disconnect from the external clock source when you test
or calibrate the device with InstaCal, as the SYNC pin drives the output.
RETRIGMODE
When using cbAInScan()/AInScan(), you can use RETRIGMODE to set up repetitive trigger events.
Resolution
When configured for single-ended mode, the resolution of the data is 13 bits (data values between 0 and
8191). However, the Universal Library maps this data to 14-bit values, so the range of data is no different
from the differential configuration. Consequently, the data returned contains only even numbers between 0
and 16383 when the NOCALIBRATEDATA option is used.