APG MLS Operating Manual

AUT OMATION

Operator’s Manual

PRODUCTS

GROUP, INC.

MLS Series

Mechanical Float Level Sensors

Rev. B1, 4/07

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MLS Series Rev. B1, 4/07

Table of Contents

Warranty .............................................................................................................3

Introduction ......................................................................................................4

Speci cations ....................................................................................................4

Operating Principle.........................................................................................5

Installation .........................................................................................................6

Wiring ..................................................................................................................8

Technical Notes ................................................................................................8

Maintenance/Inspection ..............................................................................8

Adjustment Procedure ..................................................................................9

Troubleshooting ........................................................................................... 10

Dimensions .....................................................................................................11

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Rev. B1, 4/07 MLS Series

• Warranty and Warranty Restrictions

APG warrants its products to be free from defects of material and workmanship
and will, without charge, replace or repair any equipment found defective
upon inspection at its factory, provided the equipment has been returned,
transportation prepaid, within 24 months from date of shipment from factory.

THE FOREGOING WARRANTY IS IN LIEU OF AND EXCLUDES
ALL OTHER WARRANTIES NOT EXPRESSLY SET FORTH HEREIN,
WHETHER EXPRESSED OR IMPLIED BY OPERATION OF LAW OR
OTHERWISE INCLUDING BUT NOT LIMITED TO ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.

No representation or warranty, express or implied, made by any sales
representative, distributor, or other agent or representative of APG which is
not specifi cally set forth herein shall be binding upon APG. APG shall not be
liable for any incidental or consequential damages, losses or expenses directly
or indirectly arising from the sale, handling, improper application or use of the
goods or from any other cause relating thereto and APG’s liability hereunder, in
any case, is expressly limited to the repair or replacement (at APG’s option) of
goods.

Warranty is specifi cally at the factory. Any on site service will be provided at
the sole expense of the Purchaser at standard fi eld service rates.

All associated equipment must be protected by properly rated electronic/
electrical protection devices. APG shall not be liable for any damage due
to improper engineering or installation by the purchaser or third parties.
Proper installation, operation and maintenance of the product becomes the
responsibility of the user upon receipt of the product.

Returns and allowances must be authorized by APG in advance. APG will
assign a Return Material Authorization (RMA) number which must appear
on all related papers and the outside of the shipping carton. All returns are
subject to the fi nal review by APG. Returns are subject to restocking charges as
determined by APG’s “Credit Return Policy”.

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3

MLS Series Rev. B1, 4/07

• Introduction

The MLS series mechanical  oat level sensor is designed to be used in any
open tank or vessel for top mounting and with all liquids compatible with
stainless steel. This model is intended to provide emptying and  lling control.

• Specifi cations

Electrical Characteristics

Max. Contact Rating ........... 250 V, 10 AC / 250 V, 0.3 A DC

Withstand Voltage .............. 1500 VAC 1 minute or more. (Between each

terminal and non-charge part)

Insulation Resistance ......... 100 Mý or more (measured with 500 VDC megger

between each terminals and non-charge part)

Mechanical Characteristics

Buoyancy of Float ...............Approx. 2.10 N (SG = 1)

Allowable Impact ................ 100 m/s

2

Operational Characteristics

Control Width ....................... 0.6 ~ 850 mm (see  gure on page 6)

Speci c Gravity ....................0.85 or more

Float Submersion ................ 51 mm

Gap Between Rod

and Float ................................4.5 mm

Environment

Working Temperature ........ 0 to 80°C

Application ............................Leave open tank

Other

Construction ......................... IP42

Terminal Box .........................Phenol (Cover: Polypropylene)

Wetted Parts.......................... 304 Stainless Steel (Bellows: Polycholoroprene

Rubber)

Cable Inlet ..............................Equivalent JIS F 20a (G 3/4)

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Rev. B1, 4/07 MLS Series

• Operating Principle

The  oat travels between both
 oat stops. The microswitch does not
actuate until it reaches either stops. The
lower level is actuated by the weight
of the  oat. The upper level is actuated
by the force against buoyancy of the
 oat. Hence, the hystereis established
between stops.

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MLS Series Rev. B1, 4/07

• Installation

Unpacking

The MLS Series has been thoroughly inspected and carefully packed at the
factory to prevent damage during shipment. When unpacking, exercise due
care not to subject the instrument to mechanical shock. After unpacking,
visually check the instrument exterior for damage.

Note the following points:

• Do not bend and pull the shaft extremely during installation.

• Make sure that the  oat type level switch is according to ordering
speci cations.

• Protector of metal made is put between tip of shaft and microswitch to
avoid mechanical shock during shipment. Remove the protector certainly
before using.

Installation Location

This switch should be installed in an area where the following conditions:

• Provide ample space for maintenance/inspection.

• Low relative humidity and no exposure to moisture.

• No corrosive gases (such as NH

, SO2, Cl2 and so on.)

3

• No excessive vibration

Assembly

Usually, the MLS is set to speci ed measuring length before shipment.
When not speci ed, each parts are packed severally. In that case, proceed to
assemble as follows.

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Rev. B1, 4/07 MLS Series

Notes:

• Setting length is adjusted at SG = 1.
When SG of liquid is not 1, reset both  oat travel-stops due to changing
the actuation level according to length of the actual level.

• Do not cut and do not join the rod. Otherwise the level switch may
malfunction.

Installation Method

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MLS Series Rev. B1, 4/07

• Wiring

Note:

• This switch contact is S.P.D.T. by
microswitch.

• Do not exceed the contact
ratings.

• Install solderless lugs  tted to M3

• Technical Notes

• This switch shall be mounted vertically.

• When there are surface wave motion, install stilling tube.

• Maintenance/Inspection

The following annual servicing tasks should be carried out on the switch:

• Visually check the switch exterior for damage.

• If sediment or other foreign matter are stained on wetted parts of switch,
keep wetted parts of switch clean.

• Connect ohmmeter or electronic buzzer to terminals, check the switch
actuation corresponding to  oat operation.

Reinstall and rewiring the switch after maintenance/inspection in

accordance with the Installation and Wiring sections of this manual.

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Rev. B1, 4/07 MLS Series

• Adjustment Procedure

The tension adjuster is located on one end of the shaft (see the dimension
drawing in this manual). The spring operating tension is factory set, but may
require adjustment on site, especially if the length of the operating rod is
changed. Correct operation should be checked and the spring tension should
be adjusted if necessary.

• If the switch operating position is higher than the desired level, lower the
adjuster a litte.

• If the switch operating position is lower than the desired level, raise the
adjuster a little.

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MLS Series Rev. B1, 4/07

• Trouble Shooting

Use the following information to troubleshoot the malfunctioning sensor. If

the remedies are unsuccessful, ask APG for repair or replacement.

Problem

Liquid exceeds the actuation level, but switch does not activate

Possible Causes Remedies
SG is larger than 0.85 Choose another technique
Miswiring Wire correctly
Set for improper  oat travel-stop Adjust position according to “Assembly”
Liquid immerse in  oat Replace the switch
A ected by deposit Clean the switch
Microswitch is damaged Replace the microswitch

Problem

Liquid does not exceed the actuation level, but switch activate

Possible Causes Remedies
Miswiring Wire correctly
Set for improper  oat travel-stop Adjust position according to “Assembly”
A ected by deposit Clean the switch
Microswitch is damaged Replace the microswitch

10

Automation Products Group, Inc.

APG...Providing tailored solutions for measurement applications

Tel: [phone] • Fax: [phone] • www.apgsensors.com • [e-mail]

Rev. B1, 4/07 MLS Series

• Dimensions – in./mm

Automation Products Group, Inc.

APG...Providing tailored solutions for measurement applications

Tel: [phone] • Fax: [phone] • www.apgsensors.com • [e-mail]

11

AUT OMATION

PRODUCTS

GROUP, INC.

APG...Providing tailored solutions
for measurement applications

Automation Products Group, Inc.

Tel: [phone]
1/435/753-7300
Fax: [phone]

e-mail: [e-mail]

www.apgsensors.com

Automation Products Group, Inc.

1025 W. 1700 N.

Logan, UT 84321