Milltronics MCS User manual
Instruction Manual February 2009
MCS BELT SCALE
milltronics
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© Siemens Milltronics Process Instruments Inc. 2009
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: Cardboard shipping package provides limited humidity and moisture protection. This product
can only function properly and safely if it is correctly transported, stored, installed, set up, operated, and
maintained.
This product is intended for use in industrial areas. Operation of this equipment ina residential area
may cause interference toseveral frequency based communications.
Note: Always use product in accordance with specifications.
Copyright Siemens Milltronics Process
Instruments Inc. 2009. 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 European Authorized Representative
at the following address:
Technical Publications Siemens AG
Siemens Milltronics Process Instruments Inc. Industry Sector
1954 Technology Drive, P.O. Box 4225 76181 Karlsruhe
Peterborough, Ontario, Canada, K9J 7B1 Deutschland
Email: techpubs.smpi@siemens.com
•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.
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 1
English
Milltronics MCS Belt Scale
The Milltronics MCS belt scale is a compact, rugged belt scale with stainless steel load
cells for use in mobile crushers and aggregate screening plants.
The Milltronics MCS belt scale includes a left and a right weigh beam, with one load cell
each. The addition of an idler (supplied and installed by the customer) completes the
weighing assembly. The MCS load cells generate an electrical signal proportional to load,
which is fed to the Siemens Milltronics belt scale integrator.
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 MCS
belt scale. Because the MCS 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 MCS. 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
For the complete library of Siemens Milltronics manuals,
go to www.siemens.com/processautomation.
Note: The Milltronics MCS belt scale is an accurate and repeatable force sensor. Its
performance is ultimately dependent on the conveyor system, the quality of the
installation, and the accuracy of the alignment.
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.
WARNING:
• The Milltronics MCS Belt Scale is to be used only in the manner outlined in
this manual, otherwise protection provided by equipment may be impaired.
Note: This product is intended for use in industrial areas. Operation of this equipment in
a residential area may cause interference to several frequency based communications.
Page 2 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Specifications
Accuracy1
• ± 0.5 to 1% of totalization over 25 to 100% operating range, application dependent
• ± 2% of totalization over 25 to 100% operating range, for mobile crusher applications
Load Cell
• construction stainless steel
• enclosure IP65 rated
• 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 25, 50, 100, 2502, 500 lb stainless steel
• overload safe 150% of rated capacity, ultimate 300% of rated
capacity
• temperature -40 to +75 °C (-40 to +167 °F) operating range
-18 to +65 °C (0 to +150 °F) compensated
Belt Width
• up to 1600 mm (60” CEMA) width (See
Outline Dimensions
on page 7 )
Belt Speed3
• up to 3 m/s (600 fpm)
Capacity
• up to 2400 t/h (2640 STPH) at maximum belt speed
Conveyor Incline
• ± 20° from horizontal, fixed incline
• up to ± 30° with reduced accuracy
1. Accuracy subject to: On factory approved installations the belt scale system’s totalized
weight will be within the specified accuracy when compared to a known weighed material
test sample. The test rate must be within the specified range of the design capacity and
held constant for the duration of the test. The minimum material test sample must be
equivalent to a sample obtained at the test flow rate for three revolutions of the belt or at
least ten minutes running time, whichever is greater.
2. Size normally used for mobile crusher applications.
3. Contact Siemens application engineering for consideration of higher belt speeds.
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 3
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Idler Profile
• flat to 35°
• up to 45° with reduced accuracy
Idler Diameter
• 100 to 150 mm (4 to 6”)
Idler Spacing
• 0.6 to 1.2 m (2.0 to 4.0 ft )
Weight
• up to 20 kg (44 lb), 20 kg (22 lb)/side
Interconnection (to integrator)
• < 150 m (500 ft) 18 AWG 6 conductor shielded cable
• > 150 m (500 ft) to 300 m (1000 ft.) 20 AWG 8 conductor shielded cable
Approvals
• US/Canada CSA/FM Class II, Div. 1, Groups E,F,G and Class III
• Europe ATEX II 2D Ex tD A21 IP65 T90 ºC
CE
• International IECEx Ex tD A21 IP65 T90 ºC
• Australia C-TICK
Page 4 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Operation
MCS belt scale works with an existing troughed conveyor and a Siemens integrator. As
material moves along the conveyor belt and travels over the belt scale, it exerts a force
proportional to the material load through the belt and suspended idler to the load cells.
MCS reacts only to the vertical component of the applied force. The resulting movement
in each load cell is sensed by its strain gauges. When the strain gauges are excited by
voltage from the electronic integrator, they produce an electrical signal proportional to
weight, which is then returned to the integrator. The vertical movement of the load cells is
limited by the positive overload stop incorporated into the MCS design.
calibration
weigh arm
optional
junction
box
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 5
English
Installation
The MCS is shipped from the factory as a single unit attached to a shipping frame for
protection. Each MCS 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 MCS
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) 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 MCS, install both shipping stops to their vertical position to protect
the load cells. Do not lift the MCS by the dynamic frame or subject it to shock from blows
of a hammer when trying to position it.
Notes:
• Installation shall be performed only by qualified personnel in accordance with
local governing regulations.
• Use only approved conduit and conduit fittings or cable glands to maintain NEMA
or IP rating, as applicable.
• For hazardous area installations, use only approved junction boxes, metal conduit
and conduit fittings or cable glands. Adapter supplied for ½” NPT to M20x1.5.
Discard if using ½” NPT conduit fitting.
• Adjust conveyor stringers to be rigid, straight, parallel to, and square with the belt
line in the area of the scale installation.
• Adjust pulleys to ensure that the conveyor belt tracks straight and centrally from
the head to the tail pulley.
WARNING: Use extreme caution 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 MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Installation Precautions
Scale Handling
Observe the following precautions when handling the scale.
• Do not pry on the idler, its mountings, or the load cells directly.
• Do not stand or lean on the scale.
• Lift the scale by the weigh blocks only. Do not lift the scale by the idler or idler
mounting brackets.
• Never subject the scale to sudden impacts or shocks.
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 7
English
Outline Dimensions
Note: A minimum of 2 approach and 2 retreat idlers should be aligned with the weigh
idler to within +1/32” (0.75 mm) to -0” (0 mm).
belt direction
View A-A
View A-A
150 mm
(5.91”)
75 mm
(2.95”) 300 mm
(11.81”)
160mm
(6.30”)
idler
clamping
bracket
mounting
flange
Plan View Side View
124 mm
(4.90”)
apply optional
flat bar weight
optional flat bar
weigh arm1)
227 mm
(8.95”)
1) Not recommended for inclined conveyor applications
standard base CEMA
idler or equivalent
(customer supplied)
shipping brackets
150 mm
(5.91”)
to suit
up to 1600 mm (60”) belt width
101 mm
(3.98”)
16 mm
(0.63”)
75 mm
(2.95”)
customer
supplied
stringer
Front View
Page 8 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Installation Location
The ideal placement of the Siemens Milltronics belt scale depends on the conveyor
system. This section provides guidelines to determine MCS placement.
Mobile Crushers
The MCS is installed on mobile crushers because of its durability and low profile. A belt
scale can be used effectively in a conveyor of this type, but it requires special
consideration.
Control Gates
Conveyor Belting
Variations in the number of belt plies, the cover thickness, and the type and number of
splices in a given belt can cause considerable change in the weight per unit length of the
belt. During the course of zero calibrations, belt scales average the weight of the belt over
one complete circuit of the belt. Large deviations from the average adversely affect zero
calibrations.
Recommendation: Consult your Siemens Milltronics representative to discuss
using the MCS with mobile crushers.
Note: Ensure steady and uniform material loading to the belt at or near the same
speed as the conveyor belt. The installation of a material feed control gate or similar
device improves uniform flow of material.
belt scale
control gate
uniform material
distribution
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 9
English
Head Pulley
Use caution when installing a scale in a short conveyor or when locating the scale near
the head pulley. Since head pulleys are flat-faced and carrying idlers are generally
troughed, the belt profile must change from troughed to flat in a short distance. To
accommodate this, the conveyor manufacturer designs a built-in vertical displacement of
the head pulley above the top of the center roll of the adjacent idler. To further ease this
transition, idlers of decreasing trough angles are inserted between the head pulley and
the normal run of idlers. If these measures are not taken, a considerable amount of stress
is exerted on the belt edges and the idlers adjacent to the head pulley. In turn, this stress
is transmitted to the scale causing an unreliable measurement.
Recommendation: On conveyors with 20° trough idlers throughout, install the
scale idler a minimum of two fixed 20° idlers away from the head pulley.
Recommendation: On conveyors with 35° trough idlers throughout, install the
scale a minimum of two 35° and one 20° retreat idler away from the head pulley.
belt scale
20° idlers
minimum 3 idler spaces
head pulley
belt scale
35° idlers
minimum 4 idler spaces
head
pulley
35° idlers
20°
idler
Page 10 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Recommendation: On conveyors with 45° trough idlers throughout, install the
scale a minimum of two 45°, one 35°, and one 20° retreat idler away from the head
pulley.
Recommendation: The vertical displacement of the head pulley relative to the
adjacent retreat idler is normally higher than acceptable for belt scale installations.
We therefore suggest that when you install the scale close to the head pulley, allow a
maximum of 13 mm (½”) vertical displacement between the top of the head pulley and
the top of the center roll of the adjacent roll.
belt scale
35° idlers
minimum 5 idler spaces
head
pulley
35° idler
20°
idler
45° idlers
20° idler,
center roll
13 mm (1/2”)
maximum
head pulley
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 11
English
Conveyor Curvature
Vertical curvature, whether concave (internal) or convex (external), disturbs the idler
alignment if the scale is installed in the area of curvature. Of the two types of curvature,
concave curvature is more difficult to manage because it may lift an empty belt off the
idlers around the curve, preventing a good empty belt zero balance for the scale. The
diagrams below illustrate the minimum distance the belt scale should be from the
curvature to obtain accurate results.
Concave
Convex
Belt Ploughs
We do not recommend the use of belt ploughs or any conveyor or material control device
that changes the profile of the carrying belt in or near the scale area. These devices have
a detrimental effect on the belt scale idler alignment and usually create drag on the belt
that the scale senses as a material force of load.
Recommendation: Avoid locating the scale within the tangents of scale curvature.
Recommendation: Do not install the scale within 9 m (30 ft.) of belt ploughs or
similar devices that contact the material or belt.
belt scale belt scale
minimum 12 m
(40 ft)
tangents
minimum 12 m
(40 ft)
minimum 6 m
(20 ft) minimum 12m
(40 ft)
belt scale
tangents
belt scale
Page 12 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Stacker Conveyors
Avoid installing the belt scale in any conveyor that is not a permanent structure. Because
stacker conveyors usually vary in incline, elevation, or profile, the accuracy of the belt
scale can be compromised under these conditions. A belt scale can be used effectively in
a conveyor of this type, but it requires special consideration.
Conveyor Trippers
Not as common as a conveyor with a vertical curvature, trippers can still be troublesome
to scales.
Skirt Boards and Sealing Strips
In some applications it is necessary to extend the infeed skirt boards and sealing strips
the full length of the conveyor. This can create problems in weighing accuracy caused by
the effects that the sealing strips exert when contacting the belt and indirectly upon the
idlers, especially where pinching occurs. In particular, this situation adversely affects the
zero calibrations.
Recommendation: Consult your Siemens representative to discuss using the MCS
with stacker conveyors.
Recommendation: On a conveyor with a tripper car, locate the scale using the
recommendations for vertical curves, but with the tripper fully retracted.
Recommendation: If possible, remove the skirting in the scale area. If this is not
possible, adjust the skirting to ensure the sealing strip does not put excess force on
the belt or allow pinching of material.
skirt board
pinching can
occur here
sealing strip
idler
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 13
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Installation Procedure
1. Remove the idler at the chosen location on the conveyor.
2. Remove the idler mounting brackets and cut the spine as shown.
Notes:
• Cut the idler support as shown to allow clearance when the load is applied.
• Maximum allowable idler spine for fitting to an MCS is:
Angled spine: 75 mm (3”)
Channel spine: 100 mm (4”)
before after
Page 14 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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3. Position the weigh beams so that the center of the scale idler is centered between
the adjacent approach and retreat idlers.
Ensure that the scale is centered and square to the stringers.
4. Mark the position of the weigh beams and make new mounting holes suited for M12
or ½” bolts. (Refer to
Outline Dimensions
on page 7.)
5. Place the scale on the conveyor stringers with the arrows on the weigh blocks
pointing in the direction of belt travel (retreat idlers). Mount the modified idler onto
the scale using the idler clamping brackets.
nn
belt
travel
belt
travel
approach idlers
location of removed idler
retreat idlers
A3 A2 A1 R1 R2 R3
idler
clamping
brackets
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 15
English
6. Position the weigh blocks so that they are square to the stringer.
• Shim as required between the weigh block mounting flange and the conveyor
stringer.
• Level the weigh blocks to one another and tighten the bolts sufficiently to keep
the weigh blocks in place until final adjustment.
Idler Alignment
Precise alignment is very important for maximum accuracy of the weighing system.
Improperly aligned idlers could apply undesired forces onto the weighing idler, resulting
in measurement errors.
Alignment Procedure
1. Remove the shipping stops to free each weigh block mechanism.
• Keep the stops and screws stored in a convenient place for use during
maintenance or at times when protection of the load cells is necessary.
Note: Off-center or off-square installation can result in poor belt tracking and scale
inaccuracy.
reference
idlers must be square to
stringers belt
travel
belt
travel
center
of idlers
to be in
line
A2 to R2
±0.8mm
(1/32”)
adjust idler last, leaving the
MCS 0.75 mm (1/32”) high
nn
A3 A2 A1 R1 R2 R3
load cell mounting
screws
shipping stop in
run position
overload stop clearance
0.5 mm (0.02”)
Page 16 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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2. Align and level the idler in the weighing area by raising or lowering the weigh blocks
in their mountings.
• The weighing area includes the scale and at least two idlers on each side of the
scale. For conventional flat idler roll conveyors, two additional idler rolls should
be included in the alignment procedure.
3. Adjust idlers vertically until they are all within ±0.75 mm (1/32") of each other.
• Stretch a line across the top surface of each idler roll in the scale area
approximately 25 mm (1") from each end of each side idler roll and at the centre
roll.
• Use good quality wire [0.5 mm (0.020") diameter] or equivalent nylon line to
check for alignment. The wire or string aligning lines must be able to withstand
sufficient tension to eliminate sag in the line.
4. Check that the idlers are centered and squared to the conveyor as in step 6 of the
installation procedure on page 15.
5. Tighten the weigh blocks’ mounting bolts (34 to 40.8 Nm or 25 to 30 ft lbs).
6. Install the speed sensor as described in the speed sensor instruction manual.
7. Connect the speed sensor and the MCS to the belt scale integrator. Refer to the
integrator manual and its system interconnection diagram.
Note: Off-center or off-square installation can result in poor belt tracking and scale
inaccuracy.
R2
R1
S1
A1
A2
retreat
approach
belt travel
MCS with
modified idler
wire or string for
alignment
7ML19985HN63 Milltronics MCS Belt Scale – INSTRUCTION MANUAL Page 17
English
Wiring
Notes:
• Installation shall be performed only by qualified personnel in accordance with
local governing regulations.
• Use only approved conduit and conduit fittings or cable glands to maintain NEMA
or IP rating, as applicable.
• For hazardous area installations, use only approved junction boxes, metal conduit
and conduit fittings or cable glands. Adapter supplied for ½” NPT to M20x1.5.
Discard if using ½” NPT conduit fitting.
belt direction
loadcell
‘A’ load cell
‘B’
red
loadcell
‘A’ load cell
‘B’
black
white
green
shield
red
black
white
green
shield
red
black
white
green
green
white
shld
+exc
-exc
-sig A
+sig A
-sig B
+sig B
stringer
mounted
junction box
(by customer)
Page 18 Milltronics MCS Belt Scale – INSTRUCTION MANUAL 7ML19985HN63
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Calibration
After the MCS, the speed sensor, and the integrator have been properly installed and
wired, calibration of the weighing system must be done in conjunction with the integrator.
Refer to the integrator instruction manual for programming and calibration. All instruction
manuals are available for free download at www.siemens.com/processautomation. The
calibration is initially done using the test weight(s). Material tests are recommended to
achieve the greatest accuracy. For more information about material tests, refer to the
integrator manual.
Balancing
For applications where the conveyor loading does not repeat in locations across the
width of the belt, such as side-to-side loading, electronic balancing of the two load cells
is recommended. Balancing is completed during the initial start-up, but should be
repeated if either load cell is reinstalled or replaced. Refer to the associated integrator
manual to complete the balancing procedure.
Permanently fix the test weight bracket toward the centre of the idler on the most
accessible side of the conveyor. When balancing load cells, apply a test weight to the
extreme sides (side A or B), as required. For use with optional flat bar, apply weights to
optional idler clamping brackets as illustrated on page 7.
weigh arm with standard
calibration weights
(optional flat bar weights
available)
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