Agilent Technologies 34901A User Manual page 399

Chapter 8 Tutorial
Multifunction Module
• You can control when the totalizer actually records counts by providing
a gate signal ( G and
applied to the " G " terminal enables counting and a low signal
disables counting. A TTL low signal applied to the "
counting and a high signal disables counting. The totalizer only
counts when both terminals are enabled. You can use either the G
terminal, the
gate terminal floats to the enabled state, effectively creating a
"gate always" condition.
Input Signal
(Rising Edge)
Gate Signal
(High True)
Totalizer Input
Totalizer Errors
• Noise on the totalizer input can be a problem, especially on signals
with a slow rise time. This noise can create a false indication of a
threshold crossing. For more information on cabling noise, see page 335.
• Contact bounce on external switches can create false counts.
All mechanical switches bounce when they open and close. Use an
external capacitor to filter the contact bounce.
Limit Switch
396
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terminals on the module). A TTL high signal
G
terminal, or both. When a gate is not connected, the
G
Add to Total
+5 V Switch Noise cause by bounce
Closed creates a false count
" terminal enables
G
Totalizer