User`s guide

Operation Theorem  19
4.3 Current Output and Range Control
The current output is implemented by a precision voltage-to-current
converter XTR110. The current output channel n (An) is control by
the voltage of channel n (Vn). The block diagram of the current output
channels is shown in Fig 4.1.
XTR110
50 Ohm
On Board +15V
Vn
An
External Load
(Resister R
L
= 250 Ohm typical)
A.GND
Io
Current Output
Range Control
Figure 4.1 Current output circuit
The PCI-6308A provides an on board +15V power supply. Each
current output channel is a current source, which is controlled by the
voltage of the corresponding voltage output channel. For example,
voltage output channel 3 control the current source channel 3.
The output current range is programmable. All the 8 current channels
on PCI-6308A are controlled by current range control register. There
are three kinds of output current range. Refer to the following table
and Section 5.2.9 for programming the current range by
_6308_I2V_Control function.
Mode
Input Voltage
Range
Output Current
Range
0 0~10V 0~20 mA
1 0~10V 5~25 mA
2 -- --
3 0~10V 4~20 mA