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Agilent E8462A Specifications
Relay Life
Electromechanical relays are subject to normal wear-out. Relay life depends
on several factors. The effects of loading and switching frequency are briefly
discussed below.
Relay Load.
In general, higher power switching reduces relay life. In
addition, capacitive/inductive loads and high inrush currents (for example,
turning on a lamp or starting a motor) reduces relay life. Exceeding specified
maximum inputs can cause catastrophic failure.
Switching Frequency.
Relay contacts heat up when switched. As the
switching frequency increases, the contacts have less time to dissipate heat.
The resulting increase in contact temperature also reduces relay life.
End-of-Life Detection
A preventative maintenance routine can prevent problems caused by
unexpected relay failure. The end of the life of the relay can be determined
by using one or more of the three methods described below. The best method
(or combination of methods), as well as the failure criteria, depends on the
application in which the relay is used.
Contact Resistance.
As the relay begins to wear out, its contact resistance
increases. When the resistance exceeds a predetermined value, the relay
should be replaced.
Stability of Contact Resistance.
The stability of the contact resistance
decreases with age. Using this method, the contact resistance is measured
several (5 - 10) times, and the variance of the measurements is determined.
AN increase in the variance indicates deteriorating performance.
Number of Operations.
Relays can be replaced after a predetermined
number of contact closures. However, this method requires knowledge of
the applied load and life specifications for the applied load. Typical relay life
is 10 x 10
5
relay closures with no load or 10 x 10
4
relay closures switching
full load.
Replacement Strategy
The replacement strategy depends on the application. If some relays are used
more often, or at a higher load, than the others, the relays can be individually
replaced as needed. If all relays see similar loads and switching frequencies,
the entire circuit board can be replaced when the end of relay life
approaches. The sensitivity of the application should be weighed against the
cost of replacing relays with some useful life remaining.
Note
Relays that wear out normally or fail due to misuse should not be considered
defective and are not covered by the product’s warranty.
Summary of Contents for E8462A
Page 2: ...x...
Page 10: ...8 Notes...
Page 11: ...9 Notes...
Page 12: ...10 Notes...
Page 15: ...Configuring the Agilent E8462A Multiplexer 13 Figure 1 1 Agilent E8462A Simplified Schematic...
Page 68: ...66 Using the Multiplexer...
Page 104: ...102 Agilent E8462A Relay Multiplexer Command Reference...
Page 118: ...116 Agilent E8462A Relay Multiplexer Command Reference...
Page 126: ...124 Agilent E8462A Scanning Voltmeter Application Examples Chapter 4 Notes...
Page 146: ...144 Register Based Programming...
Page 156: ...154 Index...