Totalizer
The HP 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.
Input Signal
(1V to 42V)
Gate
Input
Signal
Conditioning
Counter
Data
Threshold Jumper
+
–
Totalizer
On / Off
G
G
TTL AC
Software
Reset
GND
2.5 V Threshold (TTL)
0 V Threshold (AC)
Module Reference
8
Chapter 8 Tutorial
Multifunction Module
395
