Overall Block Diagram - Keithley SourceMeter 3A 2420 Service Manual

Figure 4-1
Overall block
diagram
Front
Display,
Panel
Controller
Keyboard
Digital
I/O Trigger,
Digital
Trigger
I/O
Link
Figure 4-2
Analog circuitry block diagram
V DAC
I DAC
Control
Analog Section
Output
Clamps
DACs
Stage
Feedback
A/D
Converter
RS-232
Microcomputer
GPIB
Interface
Digital Section
FB
V Clamp
I Clamp
IFB
VFB
VFB
IFB
+7
A/D
MUX
S
Output
Guard
Guard
Buffer
To Analog
Circuits
±15V +5V
RS-232 I/O
Analog
Power
Supply
GPIB I/O
+42
-42
+85
-85
Error Output
Amp Stage
O
Remote
+
O
-
Troubleshooting 4-5
To To
Output Stage Digital Circuits
±42V ±85V
+5V +12V
Output
Digital
Stage
Power
Power
Supply
Supply
Line In
Power Supply
Sense Output
Resistors HI
S+
Output
LO
O
S-
Protection
Guard
Out
Protection
Guard
Sense