User`s guide

317
Chapter 7 Tutorial
Multifunction Module
4
7
Totalizer
The 34907A module has a 26-bit totalizer which can count pulses at a
100 kHz rate. You can manually read the totalizer count or you can
configure a scan to read the count.
• You can configure the totalizer to count on the rising edge or falling
edge of the input signal.
• Using the hardware jumper labeled “Totalize Threshold” on the
module, you can control the threshold at which an edge is detected.
Move the jumper to the “AC” position to detect changes through 0
volts. Move the jumper to the “TTL” position (factory setting) to
detect changes through TTL threshold levels.
• The maximum count is 67,108,863 (2
26
-1). The count rolls over to “0”
after reaching the maximum allowed value.
Signal
Conditioning
Threshold Jumper
+
_
G
GND
Totalizer
On/Off
TTL
AC
Counter
Software
Reset
Data
Gate
Input
Gate
Input
Input Signal
(1V to 42V)
G
0 V Threshold (AC)
2.5 V Threshold (TTL)
34970A Refresh UG.book Page 317 Wednesday, February 17, 2010 12:34 PM