Agilent Technologies E6198B, User Manual

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Switch/Load Unit and Plug-In Cards
3
E6198B Switch/Load Unit User Manual 3-5
Built-in USB interface
Digital I/O
Current Sense
Power Bus Sense
Two DAC Channels
+5, +12V, -12V, and Spare Power
Each of the above features is described in detail in the following
sections.
USB Interface
The Switch/Load Unit switching and data transfer is controlled
by a built-in USB interface.
Figure 4-13 shows the location of
the USB interface.
Digital I/O
The Switch/Load Unit provides 8-bits of digital input, 8-bits of
digital output (Open Drain Out), and 8-bits of TTL-level digital
output (Spare Digital Out). There is no handshaking capability
in the digital I/O. Typical usage of the digital I/O includes:
Automation control
Digital control of circuitry on the Agilent E8794A Custom Card
Digital switches (for example, to indicate door open/closed)
Actuator control
Fixture ID
Digital Input
The digital input bits have TTL thresholds (0.55 Vdc for low, 3.0
Vdc for high) and are protected to ±24 Vdc. These includes the
Fixture IDs that also use standard TTL inputs, but are not
protected to ±24 Vdc.
Figure 3-3 is a typical example showing
the usage of a digital input bit.