Models 707B and 708B Switching Matrix Reference Manual
Section 4: Theory of operation
707B-901-01 Rev. B / January 2015
4-3
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Double insulate all electrical connections that an operator could touch. Double insulation ensures
the operator is still protected even if one insulation layer fails. Refer to IEC 61010-1 for specific
requirements.
•
Make sure all connections are behind a locked cabinet door or other barrier. This protects the
system operator from accidentally removing a connection by hand and exposing hazardous
voltages.
•
Use high reliability fail-safe interlock switches to disconnect power sources when a test fixture
cover is opened.
•
Where possible, use automatic handlers so operators are not required to access the DUT or other
potentially hazardous areas.
•
Provide training to all users of the system so they understand all potential hazards and know how
to protect themselves from injury.
•
In many systems, during power on, the outputs may be in an unknown state until they are
properly initialized. Make sure the design can tolerate this situation without causing operator
injury or hardware damage.
Of course, read and follow all safety warnings provided with the specific instruments to keep system
users safe.
For Model 707B or 708B, also see
(on page 1-1).
Instrument fan (Model 707B only)
The Model 707B includes an internal fan that operates continuously when power is applied to the
mainframe. The fan keeps the internal power supply and other electronics cool during operation.
AC power entry
The Model 707B or 708B is powered from standard AC mains supply through a power entry module
that is located on the rear panel of the instrument.
Universal power supply
All the power for the internal electronics and relay cards is provided by a switched-mode power
supply which is located inside the mainframe. The power supply offers improved power efficiency
compared to earlier versions of the Models 707A and 708A products.
Total power consumption requirements are listed on the rear panel of the instrument.
Microprocessor board
At the heart of the Model 707B or 708B instrument is a microprocessor board that processes all
communications. It outputs information and status messages, and executes operational commands
supplied by the operator.
For information on the commands that can be sent to the instrument, see
