Dwyer PBLT2 - Manual

Series PBLT2 Submersible Level Transducer
Specifications - Installation and Operating Instructions
Bulletin L-27
The PBLT2 Submersible Level Transducer is manufactured for years of trouble
free service in the harshest applications. The PBLT2 measures the height of liquid
above its position in the tank referenced to atmospheric pressure. The transducer
consists of a piezoresistive sensing element, encased in a 316 SS housing. Perfect
for wastewater and slurry applications with features to protect the unit from these
demanding applications. Superior lightning and surge protection utilizing dual
arrestor technology, grounded to case, eliminating both power supply surges and
lightning ground strike transients (surge protection is not guaranteed and is not
covered by warranty). Large diameter 316 SS diaphragm seal is non-clogging and
damage resistant to floating solids.
Comes equipped with a 270-pound tensile strength, shielded, vented cable.
Ventilation tube in the cable automatically compensates for changes in atmospheric
pressure above the tank. The vent tube has a filter attached to the end that will
block particles, such as dust, dirt, and water droplets, from entering the tube.
APPLICATIONS
• Wastewater: sludge pits, clarifiers, digesters; Alum tanks; Chemical storage tanks;
Oil tanks; Lime slurry; Sumps; Reservoirs.
ELECTRICAL INSTALLATION
An external power supply delivering 13-30 VDC with minimum current capability of
40 mA DC (per transmitter) is required to power the control loop. See figure below
for connection of the power supply, transmitter and receiver.
The maximum receiver load resistance (RLmax) for the DC power supply voltage
(Vsup) is expressed by the formula:
RLmax = Vsup – 13V
0.02A
Shielded cable is recommended for control loop wiring.
©Copyright 2013 Dwyer Instruments, Inc. Printed in U.S.A. 12/13 FR# M2-443430-00 Rev. 7
MERCOID DIVISION
DWYER INSTRUMENTS, INC.
P.O. BOX 258 • MICHIGAN CITY, IN 46360 U.S.A.
Phone: 219/879-8000 www.dwyer-inst.com
Fax: 219/872-9057 e-mail: [email protected]
ш3-7/16 [ш87.31]
60°
TYP
ш1/4 [ш6.35] x THRU
6 PLCS
ON A ш1-39/64 [ш40.88] B.C.
7-51/64 [198.04]
SUBMERSIBLE
CABLE
BREATHER TUBE
2
[50.80]
ш1
[ш25.40]
1/2 NPT ø1/4 x THRU
[ø6.35 x THRU]
RECEIVER PRESSURE
TRANSDUCER
RED
BLACK
SHIELD
POWER
SUPPLY
13-30 VDC mA
Example
Construction
Range
Cable Length
Options
PBLT2
PBLT2 20
XXX
40
XXX
PU
PBLT2-20-40
Cage style submersible level
transmitter, ETFE cable
In psi (5000 psi maximum)
In feet (1500 feet maximum)
Polyurethane cable
Model Number Guide
SPECIFICATIONS
Service: Compatible liquids.
Wetted Materials: 316 SS, 316L SS, epoxy adhesive; Cable: Polyether polyurethane
or ETFE.
Accuracy: ±.25% full scale.
Temperature Limits: 0 to 200ºF (-18 to 93°C).
Compensated Temperature Range: 0 to 180ºF (-18 to 82°C).
Thermal Effect: Less than ±.02%/°F.
Pressure Limit: 2X full scale.
Power Requirement: 13 to 30 VDC.
Output Signal: 4 to 20 mA DC, two wire.
Response Time: 50 msec.
Loop Resistance: 850 ohms at 30 VDC.
Electrical Connection: Wire pigtail.
Mounting Orientation: Suspended in tank below level being measured. Can be
placed on the bottom of the tank on its side.
Weight: 4.3 lb (2.0 kg).
Electrical Protection: Lightning and surge protection.
WARNING:
A voltage potential between the ground wire of the unit and the ground of other
equipment can lead to electrolytic corrosion. Always ensure the grounding system
provides an equipotential between the transmitter and the earthing ground connection.
Avoid using the power system protective ground since this will often have a significant
potential difference to the transmitter ground. Also note that dissimiliar metals in the
ground system may cause electrolysis corrosion of the transmitter or other components
in the ground system.
During installation, connect a voltmeter or ammeter between the shield ground wire
and the grounding connection. If there is a measurable voltage or current electrolytic
corrosion may be a serious possibility. If there is a potential difference then some
isolation system will be required. Improper grounding may lead to damage or poor
signal integrity.