ADInstruments PowerLab 2/20, Руководство пользователя

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Appendix A — Technical Aspects 19
Note that for either mode the trigger signal must be present for at
least 5
µ
s to register as an event. When a trigger event occurs, the
trigger indicator light will glow yellow.
When set up through software to use a voltage level, a trigger event is
registered when the voltage exceeds 2.9 volts. The trigger input is
optically isolated when set up for a voltage level. In the external
contact closure mode, the trigger input will respond to a direct short
between the centre pin and outer ring of the BNC. This can be
Figure A–2
Block diagram of the
PowerLab 4/20.
PPC403 CPU
16-bit ADC
16-bit DAC
RANGE
CONTROL
Switching
Power
Supply
C
o
m
p
ar
at
o
r
F
LAS
H
ROM
1M
x
16 D
RA
M
MULTIPLEXER
System
Glue
Chip
+1 –1
2 Differential Input
Amplifiers
2 Single-ended Input
Amplifiers
Mu
lti
Po
rt
PO
D I C
±5
V
U
SB
C
on
tr
olle
r
1M
x
16 D
RA
M
30 MHz
XTAL
2
IEC Mains
Input USB Port Serial Port I C Port
2
REAR
PANEL
FRONT
PANEL
Analog Inputs Analog Output
External Trigger Input Input 1 Input 2 + – Input 3 Input 4