Dwyer ULL - Manual (Page 5)

Installing the Unit Via Extension Pipes
If the level of the measured surface falls within the dead-zone, (blind zone) area,
you should use an extension pipe to mount the unit.
When using an extension pipe, ensure that:
• The sensor is positioned in the center of the pipe.
• The pipe extension is exactly perpendicular to the surface
of the target.
• The internal pipe diameter is at least 3.0˝ (76.2 mm) wide.
• The pipe is preferably made of plastic and must have a
smooth interior surface.
• The pipe should not protrude inside the tank.
• The tank opening should be at least the size of the internal
pipe diameter and have a smooth edge.
When installing the unit with extension pipes, measure from sensor’s lower edge
and follow these specifications:
NOTE:
1. It is always recommended to use the interference signal feature (Pr03) to locate
interfering signals when using an extension pipe.
2. The sensor's lower edge may be
a) aligned with the extension pipe's upper edge or
b) protrude it by up to 2.56˝ (6.5 cm). See Figure 3 below:
Figure 3: Extension Pipe Recommendation
Using a Conduit Adapter
1. Remove the four retaining screws from the conduit adapter cover.
2. Pull the electrical wires through the 1/2˝ NPT conduit connection or gland.
3. Connect the -24 V wire to Terminal 1, connect the +24 V wire to Terminal 2 on
the wiring block.
4. Return the adapter's cover to its place properly. Make sure that the O-ring is
placed correctly. Fasten the four retaining screws.
Figure 4: Conduit Adapter
NOTE: The conduit adapter should not exceed a torque of 50 lb-in.
To maintain a proper seal, make sure that conduit is firmly screwed to the conduit's
adaptor.
Non-Intrinsically Safe Connections
Figure 5: Non-Intrinsically Safe Positive Ground Connection
Figure 6: Non-Intrinsically Safe Negative Ground Connection
Power Supply and Load Resistance Recommendations
The following table specifies the recommended resistance range for each power
supply voltage (Non-Intrinsically Safe).
NOTE: The resistance value is the total sum of the series resistor (or PLC
resistance) and the lines resistance. The minimum voltage level on terminals
should not be less that 18 VDC.
To maintain a proper seal, make sure that conduit is firmly screwed to the conduit's
adaptor.
Ripple/Noise Parameters Recommended for the Power Supply
The following ripple/noise parameter is recommended for the power supply:
• 100 mV p-p max.
Power Supply Types Recommendations
• Prefer a regulated switching power supply.
• A rectified power supply is not recommended.
• When powering by a battery, avoid the using of switched charger.
Feeding Via PLC
• Verify that the voltage level on the unit’s terminals is at least 18 VDC.
• Check PLC specifications for grounding options.
• It is good practice to add a 150 Ω series resistor between the unit's positive
terminal and the PLC.
Pipe Length
1.64 ft (0.5 m) Internal Pipe Diameter
≥ 3.0˝ (76.2 mm)
Power Supply
Voltage
18 V
24 V
28 V Minimum
Resistance Value
0 Ω
41 Ω
68 Ω Maximum
Resistance Value
272 Ω
545 Ω
727 Ω
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