Spectrum Controls 1756sc-CTR8 - Manual (Page 53)

Chapter 6: Ladder Program Examples
43
Installation
Recommendations
High Impedance Inputs
If the input device is an open collector type if may be necessary to use a
pull up or pull down resistor in order to achieve the proper threshold
crossover point. We recommend stating is a 1kohm resistor and typing it
between the input path and ground to pull down or the input path an a +12/
24V source for pull up.
Filter Frequency Settings
Use of digital filters will insure best possible performance.
Recommendations are as follows:
Maximum Signal Input Filter
65kHz No Filtering
25kHz 25kHz Digital Filter
12kHz 25kHz and 12kHz Filters
Debounce Filter
The debounce filter is best used when the gate input is connected to low
frequency input devices such as relays or proximity switches. These
devices do not typically have any on-board debounce circuitry.