Agilent Technologies 34970A manual Totalizer Errors

Chapter 8 Tutorial

Multifunction Module

•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.

Input Signal

(Rising Edge)

Gate Signal

(High True)

Totalizer Input

Add to Total

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.

+5 V	Switch	Noise cause by bounce
	Closed	creates a false count

Limit Switch

Totalizer

396