Keithley 7707, Руководство пользователя

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15
Figure 9
Voltage connections (AC or DC)
Digital I/O
The Model 7707 has four digital input/output channels (11, 12, 13, and 14). Each I/O channel can be set as either a digital
input port or a digital output port. As shown in
Figure 10 , each port has 8 lines (bits 0 through 7).
When an I/O channel is used as an input port, the state (high or low) of each input line (bit) can be read. When an I/O channel
is used as an output port, each line (bit) can be set high or low to control external circuitry.
Figure 10
Block diagram of digital I/O channels
Digital outputs
Digital outputs are used to control logic devices, indicators, fixtures, switches, solenoids, loads, relays, etc. With one I/O
channel set as an output port, eight output lines (bits) are available. With two channels set as output ports, 16 output lines (bits)
are available. With three channels set as output ports, 24 output lines (bits) are available. And finally, with all four channels set
as output ports, 32 output lines (bits) are available.
Channel 1
HI
LO
Channel 10
HI
LO
(Channels 2–9)
+
+
DC Voltage AC Voltage
Port 1
(In or Out)
Port 2
(In or Out)
Port 3
(In or Out)
Port 4
(In or Out)
Bit
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
1-16
Channel 11
Channel 12
Bit
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
17-32
Channel 13
Channel 14