SPECIFICATIONS
RELAY PROTECTION AND
EMI SUPPRESSION
When switching inductive loads,
maximum relay life and transient EMI
suppression is achieved using exter-
nal protection (see Figures 2
and 3). Place all protection devices
directly across the load and minimize
all lead lengths. For AC inductive
loads, place a properly-rated MOV
across the load in parallel with a
series RC snubber. Use a 0.01 to
CALIBRATION
1. After configuring the DIP switches,
connect the input to a calibrated DC
source and apply power. Refer to the
terminal wiring (Figure 7).
Note: To maximize thermal stability, final
calibration should be performed in the op-
erating installation, allowing approximately
1 to 2 hours for warm up and thermal
equilibrium of the system.
2. Setpoint: set deadband at its mini-
mum (fully counter clockwise) before
adjusting the setpoint. With the de-
sired trip voltage or current input ap-
plied, adjust setpoint until the relay
trips. For HI trip calibration, start with
the setpoint above the desired trip (full
clockwise). For LO trip calibration,
start below the desired trip (full counter
clockwise).
3. Deadband: Set deadband to its
minimum (fully counter clockwise).
Set the setpoint to desired trip. Adjust
voltage/current input until relay trips.
Readjust deadband to 5% (fully clock-
wise). Set voltage/current input signal
to desired deadband position. Slowly
adjust deadband until relay untrips.
Table 1: DRG-AR-DC Input Range
switch settings (SW1 through 4)
KEY = ON
0.1
µ
F pulse film capacitor (foil polypro-
pylene recommended) of sufficient
voltage, and a 47
Ω
, 1/2W carbon
resistor. For DC inductive loads, place
a diode across the load (PRV > DC
supply, 1N4006 recommended) with
(+) to cathode and (-) to anode (the RC
snubber is an optional enhancement).
Load
Load
Diode
(optional)
Power
Power
MOV
0.1uF
Film
0.1uF
Film
Figure 3: AC Inductive Loads
Figure 2: DC Inductive Loads
47 ohm
1/2W
47 ohm
1/2W
Relay
Contacts
Relay
Contacts
+
-
Note1: All DRG Series modues are designed and tested to operate in ambient temperatures from 0
to
55
°
C, when mounted on a horizontal DIN rail. When five or more modules are mounted on a vertical
rail, circulating air or model DRG-HS01 Heat Sink is recommended.
Figure 4: DRG-AR-DC Input Range/Function
Selection (SW1) Factory Default Settings
Warning: Do not attempt to
change any switch settings
with power applied. Severe
damage may occur!
Figure 5: DRG-AR-DC Factory Calibration;
0-20mA, A-HI/B-LO, Non-Failsafe
Figure 6: Typical connections of voltage or
current inputs for DRG-AR-DC
DIMENSIONS
Figure 8: Mechanical Dimensions for DRG-AR-DC
Figure 7: Terminal Wiring Diagram for DRG-AR-DC
