Controlling The System Channel - Keithley 2750 User Manual

2-8 Close/Open Switching Module Channels
Figure 2-2
4-wire system channel connections to Model 2750 DMM
System Channel Operation:
Close Channel 101

Controlling the system channel

When a measurement channel is closed, a previous system channel (and, for a 4-wire func-
tion, its paired channel) is first opened. The closed measurement channel becomes the sys-
tem channel. When a 4-wire function is selected, the paired channel for the system
channel also closes.
and
These front panel keys
ment channel as the system channel. If there are no measurement channels available, one
of the following messages will be briefly displayed when one of these keys is pressed:
NO SCAN CARD — This message indicates that there are no switching modules (or
pseudocards) installed. All five slots are empty.
NO MEAS CARD — This message indicates that none of the installed switching mod-
ules (or pseudocards) have measurement channels. For example, the Model 7705 switch-
ing module does not have any measurement channels. Those channels cannot be internally
connected to the DMM.
Model 7700 Switching Module
Channel 1
HI
Channel 1
LO
(Closed Position
Channel 11
HI
Channel 11
LO
keys
(Figure
Model 2750 Multimeter/Switch System User's Manual
Model 2750
Relay Channel 25
Backplane
Channel
23
2-Pole/4-Pole
Shown
)
Relay Channel 24
Backplane
2-3) can be used to select the next or previous measure-
Slot 1
DMM
HI
Input
LO
Isolation
Relay
Relay
HI
Sense
LO
Isolation
Relay