User`s guide

Universal Library User's Guide Analog Output Boards - USB-3100 Series
138
Counter I/O
Counter I/O functions and methods supported
UL: cbCIn()*, cbCIn32(), cbCLoad()**, cbCLoad32()**
UL for .NET: CIn()*, CIn32(), CLoad()**, CLoad32()**
*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.
LoadValue 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
Hardware considerations
Scan options
The SIMULTANEOUS scan option can only be used with cbAOutScan() / AOutScan().
Simultaneous mode
Set the direction of the SYNCLD pin (pin 49) with the Simultaneous Mode option in InstaCal to be either
Master (output) or Slave (input).
 Specify the SIMULTANEOUS scan option and set the Simultaneous Mode option to Master to output the
internal D/A LOAD signal on the SYNCLD pin.
 Specify the SIMULTANEOUS scan option and set the Simultaneous Mode option to Slave to configure the
SYNCLD pin to receive the D/A LOAD signal from an external source. Output channels are updated
simultaneously when the SYNCLD receives the signal.
In slave mode, analog outputs may either be updated immediately or when a positive edge is seen on the
SYNCLD pin (this is under software control.) The SYNCLD pin must be at a low logic level for DAC
outputs to update immediately. If an external source is pulling the pin high, no update will occur.
When you do not specify SIMULTANEOUS, the analog outputs are updated in sequential order, and the SYNCLD
pin is ignored.
External current limiting may be required for high drive devices (USB-3110, USB-3112, USB-3114)
The voltage outputs on the USB-3110, USB-3112, and USB-3114 incorporate high-drive current output
capability. The high drive current outputs allow each of the voltage outputs to sink/source up to 40 mA
(maximum) of load current.
The voltage outputs should not be kept in a short-circuit condition for longer than the specified 100 ms. For
those applications that may potentially exceed the 40 mA maximum current limit or the 100 ms short-circuit
condition, external current limiting must be used to prevent potential damage to the USB-3100 series device.