Milltronics MMI-2 Instruction Manual

MMI-2

2 IDLER BELT SCALE

Instruction Manual PL-327 January 2001

33453270
Rev. 2.3

Safety Guidelines

Warning notices must be observed to ensur e personal safety as well as that of others, and to protect the product and the connected equipment.
These warning notices are accompanied by a clarification of the level of caution to be observed.

Qualified Personnel

This device/system may only be set up and operated in conjunction with this manual. Qualified personnel are only authorized to install and
operate this equipment in accordance with established safety practices and standards.

Warning

Note

This product can only function prope r ly and saf ely if it is correctly transported, stored, installed, set up , operated, and maintained.

:

Always use product in accordance with specifications.

:

Copyright Siemens Milltronics Process

Disclaimer of Liability

Instruments Inc. 2000. All Rights Reserved

This document is available in bou nd version and in
electronic version. We encourage user s to purchase
authorized bound manuals, or t o view electronic versions as
designed and authored by Siemens Milltronics Process
Instruments Inc. Siemens Milltronics Process Instruments
Inc. will not be responsible for the contents of partial or
whole reproductions of either bound or electronic versions.

MILLTRONICS®is a registered trademark of Siemens Milltronics Process Instruments Inc.

While we have verified the contents of this
manual for agreement with the instrumentation
described, variations remain possible. Thus we
cannot guarantee full agreement. The content s of
this manual are regularly reviewed and
corrections are included in subsequent editions.
We welcome all suggestions for improvement.

Technical data subject to change.

Contact SMPI Technical Publications at the following address:

Technical Publications
Siemens Milltronics Process Instruments Inc.
1954 Technology Drive, P.O. Box 4225
Peterborough, Ontario, Canada, K9J 7B1
Email: techpubs@milltronics.c om

For the library of SMPI instruction manuals, visit our Web site:

© Siemens Milltronics Process Instruments Inc. 2001

www.milltronics.com

TABLE OF CONTENTS

Title Page

ABOUT THIS MANUAL 1
ABOUT THE MMI-2 1
SPECIFICATIONS 2
OPERATION 3
INSTALLATION

CALIBRATION

Preamble 4
Welding 4
Load Cell Handling 4
Installation Procedure 5

General 8
Test Load 8
Zero 8
Span 8
Material Test 9
Re-Rating 9

MAINTENANCE AND SPARE PARTS 9

IDLER MOUNTING

Troughed Idler with Channel Spine 10
Troughed Idler with Pipe Spine 11
Flat Idler 12

MSI WIRING 13

OUTLINE DIMENSIONS-CEMA 14

OUTLINE DIMENSIONS-METRIC 15

PL-327 i

ABOUT THIS MANUAL

This instruction manual, PL-327, covers the installation, operation and maintenance of the MMI-2 belt scale.
It is imperative that this manual be read and understood before installation and start up of any component of

the weighing system to which the MMI-2 is being applied. Adhering to the installation and operating
procedures will insure a quick, trouble free installation and allow for the maximum accuracy and reliability of
your weighing system to be achieved.

As the MMI-2 belt scale is used in conjunction with an integrator and optional speed sensor, the instruction
manuals covering these components must be read as well.

ABOUT THE MMI-2

The Milltronics Multiple Idler (MMI-2) is a belt scale application using two Milltronics Single Idler (MSI) belt
scales in succession. The scales are designed to be inserted into belt conveyors for continuous weighing of
dry bulk solids.

Each MSI is comprised of the following: - one weighbridge c/w two load cells with cables run in a

common flexible conduit

- test weight(s)

The addition of an idler (supplied and installed by customer) to each weighbridge completes th e weighing
assembly. The MMI load cells provide an electronic signal, proportional to load, which is fed to the Milltronics
CompuScale series integrator. Thus, weighing is accomplished without disturbing the process and without
affecting the process material.

The MMI-2 is used where conveyor belt speeds or belt loading charactistics result in conditions that
necessitate extending the weighing time beyond the capibilities of a single idler scale. It is also well suited for
applications that require higher sustained accuracies, such as production control inventory accountability or
where certification for trade purposes is required.

It is important to understand that the MMI-2 is an accurate and repeatable force sensor. Its performance is
ultimately dependent upon the conveyor system and the quality of the installation and alignment.

PL-327 1

SPECIFICATIONS

Accuracy: » ± 0.25% of totalization over 5 to 1 operating range

in factory approved installations

Belt Width: » 18" to 96" in CEMA sizes

» 500 to 2000 mm in metric sizes
» refer to Outline and Dimensions

Belt Speed: » up to 4 m/s (800 fpm)

Capacity: » up to 5000 TPH at maximum belt speed

Conveyor Incline: » ± 20° from horizontial, fixed incline

» up to ± 30° with reduced accuracy

Conveyor Idler: » flat to 35°

» up to 45° with reduced accuracy

Idler Diameter: » 50 to 180 mm (2 to 7")

Idler Spacing: » 0.5 to 1.5 m (1.5 to 5.0 ft)

Load Cell: » excitation: » 10 V DC nominal

» 15 V DC maximum
» output: » 2 mV / V excitation at rated load cell capacity
» non-linearity: » 0.02% of rated output
» hysteresis: » 0.02% of rated output
» non-repeatability: » 0.01% of rated output
» capacity: » maximum ranges: 50, 100, 250, 500, 750,1000 lb
» overload: » maximum 1000% of rated capacity
» temperature: » – 40 to 85 °C (– 40 to 185 °F) operating range

» – 15 to 65 ° C ( 5 to 150 °F) internally compensated

Approvals: › CSA certified for general purpose

Hazardous Locations: › with the use of approved intrinsically safe barrier strips

Weight: › see chart, Outline and Dimensions

PL-327 2

OPERATION

Each MSI weighbridge is designed to react to the vertical component of the force being applied to it. Each MSI
consists essentially of a static assembly and a weighing assembly.

The static assembly is used to mount each MSI between the conveyor stringers and supports the weighing
assembly via its load cells.

The weighing assembly supports the scale idler and transfers the weight of the material to the load cells.
These are the active components in the weighing assembly.

As the material travels along the conveyor, a force is exerted through the suspended idler onto the weighing
assembly. The weighing assembly is forced down proportionally. The movement in each load cell is sensed
by its strain gauges. These modulate the excitiation signal from the electronic integrator to produce a signal
proportional to weight, which is returned to the integrator. The movement in the load cell is limited by the
positive stop incorporated in the design of the load cell.

idler bracket

test weight bar

Force

idler clip

idler frame

scale mounting bracket

dynamic beam

static beam

weigh
bridge

PL-327 3