8
Input Pull-ups
A 10K ohm resistor is available as a pull-up to a +5 VDC source voltage for
passive or ‘dry” inputs on each input circuit. The resistor is switched “On” or
“Off” using the two dip-switches at the top of the controller. The top switch is
associated with the first 8 inputs and the lower switch is associated with the last 8
inputs. Illustration 5 shows on of these switches in greater detail.
The default setting for each input is the “On” position. In this position, the
controller will p5 VDC to the input device.
If the input is an active input, that is it has it’s own current source, the pull-up for
that input must be switched to the “Off” position.
End-of-Line Switches
Illustration 6 shows the position of the End-of-Line switches associated with the
RS–485 terminal. You must remove the lower blank cover to gain access to these
switches
Illustration 5. Typical Input Pull-Up Switch (1 of 2)
OFF ON
OFF
ON
Illustration 6. RS–485 End-of-Line Switches
Installation
KMD-5831 PLC-28 Direct Digital Controller Installation & Operation Guide
End-of-Line Switches
