Dwyer Instruments AN24 Series, Instruction Manual

Page: 9 / 21

AN24 & AN28 Annunciators Instruction Manual
9
Power Connections
Power connections are made to a two-terminal
connector labeled POWER. See
Connectors Labeling
on page 8 . The instrument will operate regardless of
DC polarity connection. The + and - symbols are only a
suggested wiring convention.
AC or DC
POWER
Recommended External Fuse:
5 A max, Slow Blow
POWER CONNECTOR
+ -
Figure 8. Power Connections
Signal Connections
Input signal connections are made to a 14-terminal
connector at terminals labeled INPUT CHANNELS.
See
Connectors Labeling on page 8 . 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
12 ). 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 9. 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 cuto
ff or “off” state. For normally
active/saturation state or “on” transistors, program
inputs for normally closed input operation; see page
12 .
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.
COM
SIGNAL CONNECTOR
CH3 CH1 CH2 CH4
NPN
Transistor
C
B
E C
B
E
Figure 10. Open Collector NPN Transistor Inputs
Logic Level Inputs
Each logic level input is connected to an input channel
with common as the return.
Logic level inputs are factory set for normally high
active logic level inputs. For normally low input logic
levels, program inputs for normally closed input
operation, see page
12 .
Logic Level Low: 0 to 1.4 VDC
Logic Level High: 1.5 to 28 VDC
Input Impedance: Approximately 47 k
Ω
Relays and 24 V Output Connections
Relay connections are made to a six-terminal
connector labeled RELAY1 and RELAY2. See
Connectors Labeling on page 8 . The COM (common)
terminals of the relays should not be confused with
the COM (common) terminal of the signal connector.
The 24 VDC output is available at the connector
labeled 24V OUT, next to the relays connector.
24V OUT
P+ P-
RELAY 2 RELAY 1
NC NC C NO C NO
Figure 11. Relay & 24 V Output Connections