Siemens Milltronics MMI User manual

Instruction Manual September 2006
MMI BELT SCALEMMI BELT SCALE
milltronics

© Siemens Milltronics Process Instruments Inc. 2006
Safety Guidelines: Warning notices must be observed to ensure 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.
Unit Repair and Excluded Liability:
•The user is responsible for all changes and repairs made to the device by the user or the user’s
agent.
•All new components are to be provided by Siemens Milltronics Process Instruments Inc.
•Restrict repair to faulty components only.
•Do not reuse faulty components.
Warning: This product can only function properly and safely if it is correctly transported, stored,
installed, set up, operated, and maintained.
Note: Always use product in accordance with specifications.
Copyright Siemens Milltronics Process
Instruments Inc. 2006. All Rights Reserved Disclaimer of Liability
This document is available in bound version and in
electronic version. We encourage users to purchase
authorized bound manuals, or to 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.
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 contents of
this manual are regularly reviewed and
corrections are included in subsequent
editions. We welcome all suggestions for
improvement.
Technical data subject to change.
MILLTRONICS®is a registered trademark of Siemens Milltronics Process Instruments Inc.
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: [e-mail]
•For a selection of Siemens Milltronics level measurement manuals, go to:
www. siemens.com/processautomation. Under Process Instrumentation, select
Level
Measurement
and then go to the manual archive listed under the product family.
•For a selection of Siemens Milltronics weighing manuals, go to:
www. siemens.com/processautomation. Under Weighing Technology, select
Continuous
Weighing Systems
and then go to the manual archive listed under the product family.

i
Table of Contents
Milltronics MMI Belt Scale ..............................................................................................1
Safety Notes .............................................................................................................................................1
The Manual ...............................................................................................................................................1
Specifications ......................................................................................................................2
Operation ..............................................................................................................................4
Installation ...........................................................................................................................5
Welding ......................................................................................................................................................5
Load Cell Handling ..................................................................................................................................5
Installation Precautions .........................................................................................................................5
Installation Procedure ............................................................................................................................6
General Installation Requirements for Legal for Trade Applications .......................................10
Calibration .......................................................................................................................... 11
Test Load .................................................................................................................................................11
Zero ...........................................................................................................................................................11
Span ..........................................................................................................................................................11
Material Test ...........................................................................................................................................12
Re-Rating .................................................................................................................................................12
Maintenance ...................................................................................................................... 13
Idler Mounting ................................................................................................................... 14
Troughed Idler With Channel Spine ................................................................................................14
Troughed Idler With Pipe Spine .........................................................................................................15
Flat Idler ..................................................................................................................................................16
MMI Wiring ....................................................................................................................... 17
Outline Dimensions .......................................................................................................... 18

ii

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 1
Milltronics MMI Belt Scale
Milltronics MMI belt scale is a heavy-duty, high-accuracy multiple idler scale for critical
process and load-out control. The MMI uses two Milltronics MSI belt scales in
succession. The scales are designed to be inserted into belt conveyors for continuous
weighing of dry bulk solids.
Each MSI includes:
• one weighbridge c/w two load cells with leads run in liquid-tite conduit and 150 cm
(5 ft.) of interconnecting cable terminated with lugs and conduit fitting
• Siemens Milltronics test weight(s)
The addition of an idler (supplied and installed by the customer) to each weighbridge
completes the weighing assembly. The MMI load cells provide an electronic signal,
proportional to load, which is fed to the integrator. Thus, weighing is accomplished
without interrupting the process and without affecting the process material. The MMI 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.
The MMI is an accurate and repeatable force sensor. Its performance is ultimately
dependent upon the conveyor system and the quality of the installation and alignment.
Safety Notes
Special attention must be paid to warnings and notes highlighted from the rest of the text
by grey boxes.
The Manual
This instruction manual covers the installation, operation and maintenance of the MMI
belt scale. Because the MSI belt scale is used in conjunction with an integrator and
optional speed sensor, the instruction manual covering these components must be read
as well.
Please refer to this manual for proper installation and operation of any component of the
weighing system including the MMI. Adhering to the installation and operating
procedures will ensure a quick, trouble-free installation and allow for the maximum
accuracy and reliability of your weighing system.
If you have any questions, comments, or suggestions about the manual contents, please
email us at [email protected].
For the complete library of Siemens Milltronics manuals,
go to www.siemens.com/processautomation.
WARNING means that failure to observe the necessary precautions
can result in death, serious injury, and/or considerable material
damage.
Note: means important information about the product or that part of the operating
manual.

Page 2 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
Specifications
Accuracy
• ± 0.25% of totalization over 5 to 1 operating range
Load Cell
• Construction: Stainless steel with superior moisture protection
• 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 (0 to +150 °F) compensated
Belt Width
• 18" to 96" in 1” increments to suit CEMA sizes, equivalent to 500 to 2000 mm in metric
sizes
• Refer to Outline Dimensions on page 18
Belt Speed
• Up to 4 m/s (800 fpm)
Capacity
• Up to 5000 t/h (5500 STPH) at maximum belt speed
Conveyor Incline
• ± 20° from horizontal, 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)

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 3
Weight
• See chart, Outline Dimensions on page 18
Hazardous Locations
• With the use of approved Intrinsically Safe barrier strips
Approvals
• CSA certified for general purpose
• Legal for Canadian Trade - Measurement Canada approved
• Legal for US Trade - NTEP approved

Page 4 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
Operation
Each MSI weighbridge is designed to react only to the vertical component of the force
being applied to it. Each MSI consists essentially of a fixed support frame (static) and a
live frame (dynamic).
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 belt, 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 when excited by voltage
from the electronic integrator and produces a signal proportional to weight, which is
returned to the integrator. The movement in each load cell is limited by the positive stop
incorporated in the design of the load cell.
idler bracket test weight bar
force
static beam
dynamic beam
scale mounting
bracket
idler clip
idler frame
weighbridge

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 5
Installation
The MMI is shipped from the factory as a single unit attached to a shipping frame for
protection. Each MSI weighbridge must be removed from its shipping frame and
inspected for physical damage.
Be sure the conveyor design meets the installation requirements for the Milltronics MMI
belt scale. The conveyor stringers must be rigid, straight, parallel to and square with the
belt line in the area of the scale installation. The idler to be used on the scale and at least
the next two approach and retreat idlers must be of the same style and manufacture and
in good condition.
Prepare the site in accordance with the Siemens Milltronics drawing(s) provided or by
referring to the Belt Scale Applications Guidelines (7ML19985GA01).
Welding
Load Cell Handling
The load cell can tolerate very little negative displacement without damaging the load
cell.
When handling the individual MSIs, install both shipping stops to their vertical position to
protect the load cells. Do not lift the MSI by the dynamic frame or subject it to shock from
blows of a hammer when trying to position it.
Installation Precautions
The following precautions should be observed when handling the scale.
• Do not pry on the idler, its mountings, or the cells directly.
• Do not stand or lean on the scale.
• Overloading, shock, and twisting of the scal can damage the load cells.
• Do not lift the MMI by its idler.
WARNING:: Use extreme care when arc welding in the area of the belt
scale. Ensure that no welding current can flow through the belt scale. Welding
currents passing through the scale can functionally damage the load cells.

Page 6 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
Installation Procedure
1. Remove the conveyor idler currently at the desired point of installation.
2. Remove the idler foot plate and modify the idler frame at both ends of the idler as
shown below.
12.7 mm
(0.5”)
100 mm
(4”)
customer’s idler
before after

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 7
3. Insert the MSIs in the place of the removed idler. The MSI is designed to use the
existing holes in the stringer and should not require further drilling. Install the
mounting bolts and nuts but do not tighten. Remove the idler clips from the (see
diagram below). Refer to
Outline Dimensions on page 18, for working dimensions.
4. Position the individual MSIs so that they are centered and square to the stringer.
Mount the modified idler so that it is centered on the scale using the idler clips.
Tighten all mounting hardware. Refer to
Idler Mounting on page14 for alternate idler
mounting arrangements.
Position the scale so that the large arrow on the scale mounting brackets is pointing
in the direction of material flow.
Note: Be sure there is sufficient clearance between the return belt, MSI, and its test
weight (when used during the calibration procedure).
material flow
location of
removed idler
MSI belt scale
test weight(s)
test weight(s)
conveyor stringer
(typical)
idler clips

Page 8 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
5. Release the shipping stops on each MSI in order to free the weighing mechanism.
Loosen screws ‘A’ and rotate both shipping stops inward until the underside slots
slide around the screws ‘B’. Tighten screws ‘A’ to secure in place.
6. The idlers in the weighing area must be properly aligned and leveled by shimming
the scale idler (S#), the two approach (A#) and the two retreat idlers (R#) until they
are within ± 0.8 mm (1/32") of each other. Be sure to check that the idlers are
centered and squared to the conveyor during the shimming process.
‘B’ shoulder bolts
shipping stop shipping stop
‘A’ screws
CC
90°
center of idle
r
to be in line
material flow
idlers must be square to stringers
alignment of idlers
A2 to R2 to be within
± 0.8 mm (1/32”)
R 2R 1
A 1A 2 S 1 S2

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 9
7. Precise idler alignment is very important if maximum accuracy of the weighing
system is to be achieved. Misaligned idlers will result in unwanted forces being
applied on each idler in the weighing area, causing calibration and measurement
errors. Use a good quality wire or string to check for alignment. The wire or string
must be able to withstand sufficient tension in order to eliminate any sag. Adjust
shims so that all rolls of the A2 through to the R2 idlers are in line within 0.8 mm
(1/32").
Although the accepted tolerance for idler alignment is ± 0.8 mm (1/32"), the scale
mounted idler should never be lower than the adjacent idlers. Establishing good
idler alignment is the most important part of the installation procedure. Scale
accuracy is directly affected by alignment.
R 2
MSI with
modified scale
idler
approach idlers
wire or string
(for alignment) R 1
A 1
A 2
retreat idlers
S 1
S 2

Page 10 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
General Installation Requirements for Legal for
Trade Applications
1. General Conveyor Requirements:
a. Conveyor must be permanent construction.
b. The conveyor length shall be no longer than 1000 ft (300 m) nor shorter than 40 ft
(12 m) from head to tail pulley.
c. The scale must be so installed, that the nearest weigh idler of the scale is at
least 20 ft or 5 idler spaces (whichever is greater) from either the end of the
loading skirt boards or the head pulley.
d. Scale must be mounted a minimum of 40 ft from the tangent point of any curves
in the conveyor.
e. The conveyor must have a Gravity type take-up and that take-up must be
operating properly.
f. Material feed to conveyor to be uniform and centered.
g. The conveyor belting shall be no heavier than is required for normal use.
h. The conveyor must be covered on the top and sides for a minimum distance of
30 ft each end of the scale idlers. The side covers must extend down to a
distance approximately 2 ft below the return belt line.
i. The electrical power to the scale equipment must remain on at all times.
j. The belt scale integrator must be located under cover, preferably in a control
room, not subject to direct sunlight.
2. Stringer Requirements:
a. The MMI Scale shall be located close to a vertical conveyor support where
conveyor stringer deflection is near zero.
b. The conveyor Stringers in the scale area should be strong enough to limit
relative deflection to 0.8 mm (1\32").
c. The conveyor stringers must be straight to prevent any belt tracking problems.
3. Conveyor Idler Requirements:
a. The user must purchase and Install "twelve (12) Scale Quality Idlers", two idlers
to be mounted on the MMI Weighbridge and 5 idlers to be mounted on the
approach and retreat side of the MMI Weighbridge.
b. Do not use Scale Service Idlers use Scale Quality Idlers.
i. Scale Quality idlers are high tolerance idlers; for roll run-out, frame deflection
and alignment; whereas
ii. Scale Service idlers are choice idlers selected from a production run having
the best roll run-out.
c. The two scale mounted idlers must be modified to ensure proper clearance for
belt scale deflection.
d. The twelve (12) Scale Quality Idlers must be aligned to within 0.5 mm (0.02") or
better of each other.
e. The belt must remain in contact with all three rollers (center and wing rollers) of
each of the aligned idlers.
f. Idlers must be flat, 20 or 35 degree trough angle. All idlers on the conveyor must
have the same trough angle.
g. Training idlers must not be located within 60 ft of any scale weigh idler.

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 11
Calibration
After the MSI has been properly installed, calibration of the weighing system must be
done in conjunction with the integrator. Refer to the integrator instruction manual for
programming and calibration. The calibration is initially done using the supplied test load.
Material tests are recommended to achieve maximum accuracy.
Test Load
The test load value for your MSI is given on the accompanying data sheet. The value is to
be entered into the dedicated programming parameter of the integrator, in kilograms per
meter or pounds per foot. An equal number and mass of weights must be applied to each
suspension during the span calibration function.
If the actual idler spacing differs from that recorded on the design data sheet, the test
load must be recalculated as follows. Failure to do so will cause the design test load
value to be in error.
test load = Total weight of all test weights Kg or lb
idler spacing m ft
The above calculation must be performed for each MSI scale suspension using the
weights designated for that particular suspension.
Enter the average value of the two calculations into the integrator’s Test Load Parameter
(test load value “A” + test load value “B”)/2 in kilograms per meter or pounds per foot.
Zero
Perform the zero calibration as described in the Calibration section of the integrator
manual.
Span
The test load used in the calibration procedure is the two sets of test weights ( 1 to 12 )
supplied, one for each MSI suspension.
Place each set of the test weights onto the calibration weight bar of the respective MSI
as shown. Perform the span calibration as described in the Calibration section of the
integrator instruction manual.
After the span calibration has been completed, remove the test load and store it.
test weight(s)
MSI
((
))

Page 12 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
Material Test
The MMI is guaranteed to be accurate to ± 0.25% when installed on a conveyor in
accordance with this manual and meeting the qualifications outlined in the Belt Scale
Applications Guidelines (7ML19985GA01). This guarantee is based on calibrations
performed using the test weights furnished with the scale and as referenced on the
previous page.
When the existing conditions are such that the installation of the scale cannot meet the
above mentioned requirements for an approved installation it is recommended that
Material tests be performed. This will enable the user to compare the present scale
results to the results of the material tests. The scale is then adjusted or factored so that
subsequent scale calibrations with test weights will agree with actual run of material.
Re-Rating
To be sure that proper design parameters are maintained, consult your Siemens
Milltronics representative for any significant change in rate, speed and /or idler spacing
from original design specifications.

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 13
Maintenance
Keep each weighbridge clean. Accumulation of material between the fixed support
frame (static) and the live frame (dynamic) as well as around each load cell could affect
the scale accuracy.
Periodically check the alignment of the stringers and idlers in the weighing area.
When a problem arises in the conveyor, it is possible that the scale will be affected.
Therefore, periodic conveyor maintenance is important to proper scale operation which
should include:
• lubrication of all pulleys and idlers
• proper belt tracking and training
• proper belt cleaning and scraping
• proper take up operation
• proper material feeding and spillage
•control.
You can observe the integrity of the load cells by performing zero and span calibrations. If
the zero and span deviations display a continuous unidirectional drift or the system
becomes uncalibratable for no apparent mechanical reason, the load cells may be
suspect.
Spare Parts
The only spare part recommended for the MSI is the load cell. Refer to the load cell
nameplate for the proper size and model number.
Re-balance any load cell that has been replaced. Refer to the Load Cell Balancing
Procedure For Four Load Cells in the integrator manual.
Maintenance Precautions
• When welding near the scale, do not allow current to pass through the belt scale.
• Reset the shipping stops to reduce physical shock to the load cells during
maintenance.
• Recalibrate the scale after maintenance and prior to use.

Page 14 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
Idler Mounting
The MSI is usually installed in conveyors employing conventional rigid structure idlers.
Within this type of idler, construction will vary depending on the manufacture and the
application. The idler depicted in the Installation Procedure section on page 6 uses an
angle iron spine. The following images depict alternate idler construction and tips on how
they should be modified and installed.
Troughed Idler With Channel Spine
idler modification
idler installation
gusset reinforcement if
required. See
Installation Procedure
on page 6.
12.7 mm
(0.5”)
100 mm
(4”)
customer’s idler
foot pads welded
to idler spine
before after before
customer bolts
(4 places)
idler clip

7ML19985DR02 Milltronics MMI Belt Scale – INSTRUCTION MANUAL Page 15
Troughed Idler With Pipe Spine
idler modification
idler installation
gusset reinforcement if
required. See
Installation Procedure,
on page 6.
12.7 mm
(0.5”)
100 mm
(4”)
customer’s idler
f
oot pads welded
t
o idler spine
after
before
customer bolts
(4 places)
idler clip
welded to idler pipe
(be sure idler is square to
scale & conveyor frame)

Page 16 Milltronics MMI Belt Scale – INSTRUCTION MANUAL 7ML19985DR02
Flat Idler
idler modification
idler installation
In most applications standard
conveyor manufacturers’
brackets cannot be used,
replacement brackets (as
shown) are needed.
12.7 mm
(0.5”)
customer’s idler
after
before
customer bolts
(4 places)
idler clip