PD154 & PD158 Vigilante
®
II Annunciators
Instruction Manual
14
Signal Connections
Input signal connections are made to a 14-terminal connector at
terminals labeled INPUT CHANNELS on Figure 2. The COM (common)
terminal is the return for all types of input signals.
Normally Open (NO) or Normally Closed (NC) Switches
The following figure shows an example of normally open or normally
closed contact inputs.
Programming a channel for a normally open or normally closed contact is
done with the front panel pushbuttons (see page
22
). All channels are
initially set for normally open contacts. Each contact is wired across an
input channel and common.
COM
SIGNAL CONNECTOR
CH3
CH1
CH2
CH4
NO
CONTACT
NC
CONTACT
Figure 4. NO/NC Contact Inputs
Open Collector NPN Transistor
Each transistor collector is connected to a separate input channel and all
emitters connected to common. All channels are factory set for transistor
inputs normally in the cutoff or ”off” state. For normally active/saturation
state or “on” transistors, program inputs for normally closed input
operation; see page 22.
Open circuit voltage is approximately 3.3 VDC provided by a 47 k
Ω
internal pullup resistor.
The following figure shows an example of open collector NPN transistor
inputs.
