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A
Switch/Load Unit And Card Specifications
Relay Characteristics (Agilent E8782A and E8783A)
Parameter
Type
Switching Speed
Switching Characteristics
Life Time
Relay Life
End-of-Life Detection
A-14
Specification
Dry reed
Close: 500 µs
Open: 300 µs
1.0A carry
0.5A while switching
200VDC Switching voltage
@ No load: 1x10
@ Full load: 1x10
Electromechanical relays are subject to normal wear-out. Relay
life depends on several factors including loading and switching
frequency.
Relay Load. Higher power switching, capacitive/inductive
loads, and high inrush currents (e.g. turning on a lamp or
starting a motor) reduces relay life. Exceeding specified
maximum inputs can cause catastrophic failures.
Switching Frequency. Relay contacts heat when switched. As
switching frequency increases, the contacts have less time to
dissipate heat. The resulting increase in contact temperature
reduces relay life.
Use preventative maintenance routine to reduce problems
caused by relay failure. Use the methods below to determine
when a relay may be near failure. The best method (or
combination of methods) and the failure criteria depend on the
application in which the relay is used.
Contact Resistance. As relays wear out, contact resistance
increases. For the E8792A 32-Pin Matrix Card, the total
resistance measured through an external instrument connector
to an analog bus connector is less than 1 , mostly trace
resistance. An increase of 1-2 s indicates relay deterioration.
Stability of Contact Resistance. The stability of contact
resistance decreases with age. Measure the contact resistance
several (5 - 10) times and note the variance. Increased variance
indicates deteriorating performance.
8
operations
5
operations
E6198B Switch/Load Unit User Manual
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