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PRINCO L3520 Instruction Manual

Point level controllers with null-kote
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Instrumentation designed
with the user in mind
INSTRUCTION MANUAL
PRINCO MODELS L3520 & L3521
POINT LEVEL CONTROLLERS
with NULL-KOTE™
PRINCO INSTRUMENTS INC.
1020 INDUSTRIAL BLVD.
SOUTHAMPTON, PA 18966
TEL: 800-221-9237, 215-355-1500
FAX: 215-355-7766
WEB SITE: www.princoinstruments.com
E-MAIL: info@princoinstruments.com
Rev. 1, 16 Oct 01

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Summary of Contents for PRINCO L3520

  • Page 1 Instrumentation designed with the user in mind INSTRUCTION MANUAL PRINCO MODELS L3520 & L3521 POINT LEVEL CONTROLLERS with NULL-KOTE™ PRINCO INSTRUMENTS INC. 1020 INDUSTRIAL BLVD. SOUTHAMPTON, PA 18966 TEL: 800-221-9237, 215-355-1500 FAX: 215-355-7766 WEB SITE: www.princoinstruments.com E-MAIL: info@princoinstruments.com Rev. 1, 16 Oct 01...

  • Page 2: Table Of Contents

    Section 1. Description A. General Description B. Functional Description C. L850, L860 & L870 Series Probe Description Section 2. Specifications A. 1. L3520 & L3521 Level Controllers A. 2. L850, L860 & L870 Series Probes Section 3. Installation A. Inspection B. Grounding C.
  • Page 3 Table of Contents Figure 3-6. Electrical Connections, 24 Vdc Figure 3-7. Typical Integral FM Approved System Figure 3-8. FM Approved Model Numbers Figure 4-1. L3520/21 Adjustment and Indicator Locations Figure 4-2. Conductive Process Calibration Procedure Figure 4-3. Non-Conductive Process Calibration Procedure...

  • Page 4: Section 1. Description

    B. Functional Description The Models L3520 and L3521 are part of a new generation of point level control switches that incorporates advanced technology to bring forth enhanced features and performance. The basic function of the device is to detect the presence or absence of process material within a storage tank or holding vessel, and to announce the process material detection in the form of an “alarmed”...
  • Page 5 Two sets of Form C (DPDT) contacts are provided via a six position terminal block (TB1) located on the top printed circuit board of the L3520/21. For the L3520, both contacts are rated at 10 amps at 115 Vac; for the L3521, one set of contacts is rated at 2 amps and the other at 10 amps at 115 Vac.

  • Page 6: L850, L860 & L870 Series Probe Description

    The L3520/21 provides a Dead Band adjustment. A single turn DEAD BAND pot is provided on the top of the unit. The Dead Band is the span between the level at which the L3520/21 recognizes the change from absence to presence, and the level at which it recognizes the change from presence to absence.
  • Page 7 The guard contact is made by means of a ½ inch diameter spring which projects from the bottom of the L3520/21 bottom circuit board. This spring fits concentrically around the spring-loaded pin and touches the guard contact on the probe. The hub of the probe serves as the ground element.
  • Page 8 Section One Description Figure 1-2 Standard L853 Probe, Descriptive Drawing Figure 1-3 Standard L870 Probe, Descriptive Drawing...

  • Page 9: Section 2. Specifications

    • CONTROL RELAY CONTACTS L3520: Two sets of form C contacts, rated at 10 amperes, 115 Vac or 26 Vdc, resistive load. L3521: Two sets of form C contacts; one rated at 10 amperes, 115 Vac or 26 Vdc; the other rated at 2 amperes, 115 Vac or 26 Vdc, resistive load.

  • Page 10: 2. L850, L860 & L870 Series Probes

    Specifications • FM APPROVAL Factory Mutual Approved when used with any one of Princo Probe Models L853, L854, L855, L857, L861, L862 or L863 and various L100 Series Probes. See Fig. 3-8 for details. 2. L850, L860 & L870 SERIES PROBES •...

  • Page 11: Section 3. Installation

    Installation A. Inspection The L3520/21 Level Controller is normally supplied with one of the Princo L850, L860, or L870 Series Level Probes. The L3520/21 and probe are shipped in separate packages. Carefully remove each package's contents and check each item against the packaging list.
  • Page 12 Continuity should exist between the storage vessel and the equipment electronic housing. Less than 1 ohm resistance should exist between these two points. See Figure 3-4. Figure 3-1 L3520/21 Dimensional Drawing...

  • Page 13: Electrical Connections

    Extended Guard Installation D. Electrical Connections Remove the lid of the L3520/21 electronic housing in preparation for connection of input and output wires. Before drawing wires into the equipment housing, it may be necessary to remove the electronic chassis. To do so, unfasten the two 8-32 mounting screws which are located on...
  • Page 14 Section Three Installation either side of the terminal strips. Once screws are unfastened, the chassis may be lifted or removed from the housing. The power and relay contact wires may now be pulled through the one inch NPT wiring port. Connect the 115 Vac or 230 Vac power line wires: Hot (H), Neutral (N), and Ground (G) respectively, to the right terminal strip (TB2) as shown in Figure 3-5.
  • Page 15 Section Three Installation Figure 3-5 Electrical Connections, 115 Vac and 230 Vac Figure 3-6 Electrical Connections, 24 Vdc...
  • Page 16 Section Three Installation E. Installation in Hazardous Areas The outline which follows points out some of the major requirements of the NEC's (National Electric Code) Section 501, as it relates to typical level control installations. WARNING ! For applications which MUST BE explosion-proof and/or weatherproof, it is the customer's responsibility to install the required conduit, seals, wiring, etc., which meet national, as well as applicable local and plant safety codes.
  • Page 17 Figure 3-8. FM Approved Model Numbers...

  • Page 18: Section 4. Adjustments And Operation

    A. Initial Checkout 1. Refer to Figure 4-1 for L3520/21 adjustment and indicator locations. 2. Install the L3520/21 Level Controller with Probe as presented in Section 3 of this manual. 3. Apply power to the unit. 4. Perform Section Four, step H.1: Basic Electronic Checks.
  • Page 19 Section Four Adjustments and Operation but the process material, contacts the probe. A clip lead must be connected from the L3520/21 metal housing to the metal wall of the vessel used. Whether adjustments are made under simulated conditions, or in the actual proper installation, the following procedure must be performed: 1.
  • Page 20 Section Four Adjustments and Operation Figure 4-2 Conductive Process Calibration Procedure...
  • Page 21 Horizontal probe mounting is preferred (see Section 3C). The procedure must be done with the L3520/21 properly installed in the intended storage tank, and with the intended process material. All or most of the probe may need to be covered. The angle between the adjustment marks may be quite small with non-conductive process materials.
  • Page 22 Section Four Adjustments and Operation Non-conductive Process Calibration Procedure Figure 4-3...

  • Page 23: Alarm Action

    Adjustments and Operation C. Alarm Action The L3520/21 is in the normal “non-alarmed” state when it’s control relay is energized. The unit is in the “alarm” state when its internal control relay is de-energized. Hence, if the unit lost power, the internal control relay would de-energize, and an “alarm” condition would occur.

  • Page 24: Relay Test Function (L3520 Only)

    Although the L3520/21 is not designed as a zone controller, it may be used as such in some applications. The on/off zone can be established experimentally by varying the DEAD BAND pot.

  • Page 25: Troubleshooting Guide

    ü The LED should switch crisply from Green to Red or from Red to Green. It should never hang in between in an orange color. If the unit fails any of the above checks, return the L3520/21 electronic chassis to the factory for repair or replacement.
  • Page 26 Section Four Adjustments and Operation ü There may have been a change in the dielectric constant of the process material. This would change the flow of RF current through the probe, effectively shifting the switch point. Solution: RF impedance technology is designed to operate with materials having a constant dielectric constant (therefore, a constant RF conductivity).

  • Page 27: Section 5. Equipment Service

    8. Person to contact at your Company 9. Return (Ship to) Address Princo level instruments are covered by a 10 year limited warranty. You will not be charged if it is determined that the problem is covered under warranty. Please return your equipment with freight charges prepaid.

This manual is also suitable for:

L3521

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