Keithley 7037, Инструкция по эксплуатации

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Card Connections and Installation
4-2
Handling precautions
To maintain high impedance isolation, care should be taken
when handling the relay and connector cards to avoid con-
tamination from such foreign materials as body oils. Such
contamination can substantially lower leakage resistances,
thus degrading performance.
To avoid possible contamination, always grasp the relay and
connector cards by the side edges or shields. Do not touch
the board surfaces or components. On connectors, do not
touch areas adjacent to the electrical contacts. Dirt buildup
over a period of time is another possible source of contami-
nation. To avoid this problem, operate the mainframe and
card in a clean environment.
If a card becomes contaminated, it should be thoroughly
cleaned as explained in Section 6.
Digital I/O connections
Voltage source jumper
Digital output high uses the in5V source as the high
logic level. If higher voltages are required, a user-supplied
voltage can be used (42V maximum). At the factory, the
internal jumper is set to use the in5V source.
CAUTION
Failure to set J201 to the Vext position
when using external pull-up voltages
may result in damage to the output
drivers.
A plug-in jumper for the bank allows you to select the inter-
nal +5V source or an external source. In Figure 4-1, the
banks are using the external voltage source.
Figure 4-1
Voltage source jumper for output channels
The voltage source jumper is located on the connector board
as shown in Figure 4-2. Figure 4-3 shows how the plug-in
jumper is installed on J201.
Pull-up resistors
When interfacing outputs to high-impedance devices (i.e.,
logic devices), pull-up resistors are used to achieve the
appropriate logic level. These resistors are installed at the
factory.
31
34
U203 U201 U202
J201
5V
V
ext
32
33
35
38
36
37
39
40