Section 13: Model 3750 multifunction control card
Series 3700A Switch and Control Cards Reference Manual
13-8
3700AS-909-01 Rev. B / December 2011
Counter/totalizer
CAUTION
Do not exceed the maximum voltage and currents as listed on the Model 3750 specifications. Unused
inputs should not be left floating but should be tied to ground or an appropriate DC voltage.
There are four separate totalizer channels, numbered 6 through 9, on a Model 3750 card. The
threshold voltage is programmable and can be either 0 V or a TTL level (1.5 V). Counting occurs
when the rising or falling edge on the input signal passes through the defined threshold. The edge to
be counted can be programmed to be either rising or falling. The power on default is rising edge, TTL
level threshold.
NOTE
When setting up the edge to be detected or changing the threshold, any existing counts are cleared.
Using the card to count closures
The following examples demonstrate how to use the card to count closures of a door switch
connected to the first totalizer in Slot 1, using the Channel 1005.
Figure: Switch count example
Figure 69: Switch count example
