Filter
Top Products
• You can control when the totalizer actually records counts by providing
a gate signal (
G and G terminals on the module). A TTL high signal
applied to the “
G” terminal enables counting and a low signal disables
counting. A
TTL low signal applied to the “G” terminal enables counting
and a high signal disables counting. The totalizer only counts when
both terminals are enabled. You can use either the
G terminal, the G
terminal, or both. When a gate is not connected, the gate terminal
floats to the enabled state, effectively creating a “gate always” condition.
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.
Input Signal
(Rising Edge)
Add to Total
Totalizer Input
Gate Signal
(High True)
Totalizer
Limit Switch
Noise cause by bounce
creates a false count
Switch
Closed
+5 V
Chapter 8 Tutorial
Multifunction Module
396