Milltronics MMI-2 Instruction Manual

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MMI-2
2 IDLER BELT SCALE
Instruction Manual PL-327 January 2001
33453270 Rev. 2.3
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Safety Guidelines
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
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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
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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
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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
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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
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INSTALLATION
PREAMBLE
The MMI-2 is shipped from the factory, attached to a frame for protection. Each MSI weighbridge must be removed from its shipping frame and inspected for physical damage.
Insure that the conveyor design meets the installation requirements for the Milltronics MMI-2 scale. The conveyor stringers must be rigid, straight, parallel to and square with the belt line in the area of the scale installation. The idlers 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 Milltronics drawing(s) provided or by reference to Milltronics instruction manual PL-328, Applications Guidelines.
WELDING
Extreme caution should be used when arc welding in the area of the belt scale. Insure that no welding current can flow through the belt scale. Welding currents through the scale are sufficient to functionally destroy the load cells.
LOAD CELL HANDLING
The load cell can tolerate very little negative displacement, otherwise the load cell will be functionally destroyed. When handling the individual MSI’s install both shipping stops to their vertical position to protect the load cells.
Do not lift the MSI’s by the weighing assembly or subject it to shock from blows of a hammer when trying to position it.
DO NOT STAND OR WALK ON THE SCALE.
OVERLOADING, SHOCK AND TWISTING OF THE SCALE CAN ALL
FUNCTIONALLY DESTROY THE LOAD CELLS.
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INSTALLATION PROCEDURE
1. Remove the conveyor idlers currently at the desired points of installation.
2. Remove the foot plates and modify the idler frame at both ends of the idlers as shown .
customer’s idler
12.7 mm (0.5")
100 mm (4")
before
after
3. Insert the MSI’s in the place of the removed idlers. 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. Refer to Outline and Dimensions.
location of removed idlers
material flow
test weight(s)
test weight(s)
MSI belt scales
Insure that there is sufficient clearance between the return belt and the MSI and test weight (when used during the calibration procedure).
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4. Position the individual MSI’s such that they are centered and square to the stringer. Mount the modified idlers such that they are centered onto the scale using the idler clips. Tighten all mounting hardware. Refer to Idler Mounting for alternate idler mounting arrangements.
Orient the scale so that the large arrow on the scale mounting brackets is pointing in the direction of material flow.
idler clips
conveyor stringer (typical)
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 shoulder bolts ‘B’. Tighten screws ‘A’ to secure in place.
‘A’ screws
shipping stop
‘B’ shoulder bolts
PL-327 6
shipping stop
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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.
Center of idlers to be in line
90°
CC
idlers must be square to stringers
R 1
R 2
alignment of idlers A 2 to R 2 to be within
±
0.8 mm (1/32")
A 2
material flow
S 1
S 2A 1
7. Precise idler alignment is very important if maximum accuracy of the weighing system is to be achieved. Misaligned idlers will result in unequal 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 as to eliminate any sag. By shimming, make the necessary adjustments to bring all the rolls of the A2 through to the R2 idlers in line within 0.8 mm(1/32").
A 2
approach idlers
A 1
S 1
S 2
MSI with modified scale idler
wire or string (for alignment)
PL-327 7
R 1
retreat idlers
R 2
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Although the accepted tolerance for idler alignement is ±0.8 mm (1/32"), the scale mounted idlers 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. Proper attention must be given here.
CALIBRATION
GENERAL
After the MMI-2 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 each MSI is the same and 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 feet. 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 per MSI kg lb
idler spacing m ft
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.
( )
OR
( )
MSI
PL-327 8
test weight(s)
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MATERIAL TEST
The MSI is guaranteed to be accurate to ±0.25% when installed on a conveyor in accordance with this manual and meeting the qualifications outlined in Manual PL-328 "MMI Applications Guidlines". This guarantee is based on calibrations performed using the test weights furnished with the scale and as previously referenced.
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.
At least 3 samples of a minimum of 10 minutes duration at normal capacity should be taken to insure repeatability. Refer to "Material Test" and subsequent "Factoring" sections of the integrator manual.
RE-RATING
Any significant change in rate, speed and /or idler spacing from original design specifications should be referred to your local Milltronics office to insure that proper design parameters are maintained.
MAINTENANCE AND SPARE PARTS
Each weighbridge should be kept clean. Accumulations of material between the weighing assembly and static assembly as well as around each load cell can be detrimental to the weighing accuracy.
Periodically check the mechanical integrity of the scale and alignment of the stringers and idlers within the weighing area.
The integrity of the load cells can be seen when zero and span calibrations are performed. 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.
Replacement of load cell(s) will require a re-balancing of the load cells. Refer to the load cell balancing procedure for four load cells in the integrator manual.
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.
Precautions :
» when arc 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 after maintenance and prior to use.
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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 uses an angle iron spine. The following depicts alternate idler construction and tips on how they should be modified and installed.
TROUGHED IDLER WITH CHANNEL SPINE
gusset reinforcement if required, see Installation Procedure
customer’s idler
12.7 mm (0.5")
foot pads welded to idler spine
before after
100 mm (4")
idler modification
idler clip
idler installation
PL-327 10
customer bolts (4 places)
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TROUGHED IDLER WITH PIPE SPINE
customer’s idler
12.7 mm (0.5")
foot pads welded to idler spine
before after
100 mm (4")
idler modification
idler clip
idler installation
PL-327 11
customer bolts (4 places)
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FLAT IDLER
customer’s idler
before after
in most applications standard conveyor manufacturers’ brackets cannot be used, replacement brackets (as shown) are needed
12.7mm (0.5")
idler modification
customer bolts (4 places)
idler installation
PL-327 12
idler clip
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MMI-2 WIRING
load cell ‘A’ (‘C’)
see detail ‘A’
load cell ‘A’
MSI #2
belt travel
MSI #1
load cell ‘B’ (‘D’)
load cell ‘B’
DETAIL ‘A’
conduit and connector
load cell
‘A’
+
E X E
E X E
MSI #1
+
S
S
I
I
G
G
A
A
to integrator
belt travel
load cell
‘B’
load cell
‘A’
MSI #2
load cell
‘B’
customer
junction
box
+
S
S
S
I
G
B
H
I
I
G
E L
B
D
+
E
E
X
X
E
E
+
S
S
I
I
G
G
A
A
+
S
I
G B
S
S
H
I
I
G
E L
B
D
to integrator
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OUTLINE DIMENSIONS - CEMA
‘C’
178 mm (7")
‘D’
‘A’
‘B’
conveyor mounting scale minimum drop-in ‘C’ ‘D’ weight belt width width ‘A’ width ‘B’
18 " 27 " 24.5 " 9.5 " 5.5 " 82 lb 20 " 29 " 26.5 " 9.5 " 5.5 " 85 lb 24 " 33 " 30.5 " 9.5 " 5.5 " 90 lb 30 " 39 " 36.5 " 9.5 " 5.5 " 99 lb 36 " 45 " 42.5 " 9.5 " 5.5 " 107 lb 42 " 51 " 48.5 " 9.5 " 5.5 " 116 lb 48 " 57 " 54.5 " 12 " 8" 162 lb 54 " 63 " 60.5 " 12 " 8" 174 lb 60 " 69 " 66.5 " 12 " 8" 185 lb 72 " 81 " 78.75 " 12 " 8" 235 lb 84 " 93 " 90.75 " 12 " 8" 261 lb 96 " 105 " 102.75 " 12 " 8" 288 lb
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LINE DIMENSIONS - METRIC
‘C’
178 mm (7")
‘D’
‘A’
‘B’
conveyor mounting scale minimum drop-in ‘C’ ‘D’ weight
belt width width ‘A’ width ‘B’
500 650 800
800 1000 1000 1200 1200 1400 1600 1800 2000
mm mm mm mm
mm mm mm mm mm mm mm mm
740
mm
890
mm
1040
mm
1090
mm
1240
mm
1290
mm
1450
mm
1540
mm
1650 / 1740 1900 / 1940 2100 / 2140 2300 / 2340
mm mm mm mm
677
mm
827
mm
977
mm
1027
mm
1177
mm
1227
mm
1387
mm
1477
mm
1587 / 1677 1837 / 1877 2037 / 2077 2237 / 2277
mm mm mm mm
241 241 241 241 241 305 305 305 305 305 305 305
mm mm mm mm mm mm mm mm mm mm mm mm
140 140 140 140 140 203 203 203 203 203 203 203
mm mm mm mm mm mm mm mm mm mm mm mm
37 kg 40 kg 44 kg 48 kg 52 kg 73 kg 78 kg 83 kg 88 kg 93 kg 98 kg
103 kg
PL-327 15
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Siemens Milltronics Process Instruments Inc. 1954Technology Drive, P.O. Box 4225 Peterborough, ON.Canada K9J 7B1 Tel: (705) 745-2431 Fax: (705) 741-0466 www.milltronics.com
c
Siemens Milltronics Process Instruments Inc. 2001
Subject to change without prior notice
*7ML19981dr01*
Printed in Canada
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