4.4 The Settling Time
If the
channel number
or
gain factor
is changed, the hardware need
extra time for
signal ready
. This is called the settling time. This limitation will apply both to the
Fixed-
channel mode
and
MagicScan mode
AD conversions. So the user must take care to avoid the
settling error. In the MagicScan mode, the MagicScan controller will control all details. The
MagicScan controller will change the channel number and gain control just after every pacer
trigger signal.
Therefore the limitation is
“
settling time <= pacer timer
"
in MagicScan
mode.
4.5 How to Delay the Settling Time
In the software trigger mode, the software operation is given as follows:
1.
send software trigger pulse
2.
delay the settling time
3.
read the A/D data
The
P180X_DelayUs(...)
is a machine independent timer function. Therefore this
function is suitable to delay the settling time. In the pacer trigger mode, the software does
not have to call P180X_DelayUs(...) The only limitation is that the pacer timer must be
longer than the settling time. Refer to Sec. 4.1 for settling time details.
PCI-1202/1602/1800/1802 Hardware User’s Manual
(
Ver.4.2, Dec/2009, PMH-014-42)---- 68