Junction Box
Type KPF-4 / KPF-6 / KPF-8 / KPF-10
T
EECCHHNNIICCAALL
T
M
AANNUUAAL
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Flintec GmbH
Bemannsbruch 9
74909 Meckesheim
GERMANY
www.flintec.com
RIGHTS AND LIABILITIES
All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by
any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of Flintec
GmbH
No patent liability is assumed with respect to the use of the information contained herein. While every
precaution has been taken in the preparation of this book, FLINTEC assumes no responsibility for errors or
omissions. Neither is any liability assumed for damages resulting from the use of the information contained
herein.
The information herein is believed to be both accurate and reliable. FLINTEC, however, would be obliged to
be informed if any errors occur. FLINTEC cannot accept any liability for direct or indirect damages resulting
from the use of this manual.
FLINTEC reserves the right to revise this manual and alter its content without notification at any time.
Neither FLINTEC nor its affiliates shall be liable to the purchaser of this product or third parties for damages,
losses, costs, or expenses incurred by purchaser or third parties a s a result of: accident, misuse, or abuse of
this product or unauthorized modifications, repairs, or alterations to this product, or failure to strictly comply
with FLINTEC operating and maintenance instructions.
FLINTEC shall not be liable against any damages or problems arising from the use of any options or any
consumable products other than those designated as Original FLINTEC Products.
NOTICE: The contents of this manual are subject to change without notice.
Copyright © 2007 by Flintec GmbH, 74909 Meckesheim, Bemannsbruch 9, Germany
SAFETY INSTRUCTIONS
CAUTION READ this manual BEFORE operating or servicing this equipment. FOLLOW
these instructions carefully. SAVE this manual for future reference. DO NOT allow untrained
personnel to operate, clean, inspect, maintain, service, or tamper with this equipment.
ALWAYS DISCONNECT this equipment from the power source before cleaning or performing
maintenance. CALL FLINTEC ENGINEERING for parts, information, and service.
WARNING ONLY PERMIT QUALIFIED PERSONNEL TO SERVICE THIS EQUIPMENT.
EXERCISE CARE WHEN MAKING CHECKS, TESTS AND ADJUSTMENTS THAT MUST BE
MADE WITH POWER ON. FAILING TO OBSERVE THESE PRECAUTIONS CAN RESULT
IN BODILY HARM.
WARNING FOR CONTINUED PROTECTION AGAINST SHOCK HAZARD CONNECT
TO PROPERLY GROUNDED OUTLET ONLY. DO NOT REMOVE THE GROUND PRONG.
WARNING DISCONNECT ALL POWER TO THIS UNIT BEFORE REMOVING THE
FUSE OR SERVICING.
WARNING BEFORE CONNECTING/DISCONNECTING ANY INTERNAL ELECTRONIC
COMPONENTS OR INTERCONNECTING WIRING BETWEEN ELECTRONIC EQUIPMENT
ALWAYS REMOVE POWER AND WAIT AT LEAST THIRTY (30) SECONDS BEFORE ANY
CONNECTIONS OR DISCONNECTIONS ARE MADE. FAILURE TO OBSERVE THESE
PRECAUTIONS COULD RESULT IN DAMAGE TO OR DESTRUCTION OF THE
EQUIPMENT OR BODILY HARM.
CAUTION OBSERVE PRECAUTIONS FOR HANDLING ELECTROSTATIC SENSITIVE
DEVICES.
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
Page 2 of 8
TABLE OF CONTENTS
RIGHTS AND LIABILITIES................................................................................................................................2
SAFETY INSTRUCTIONS ................................................................................................................................. 2
TABLE OF CONTENTS..................................................................................................................................... 3
INTRODUCTION AND TECHNICAL DATA...................................................................................................... 4
MECHANICAL INSTALLATION........................................................................................................................ 4
ELECTRICAL CONNECTIONS......................................................................................................................... 4
LOAD CELL CABLE CONNECTION ................................................................................................................ 5
OUTPUT CABLE CONNECTION...................................................................................................................... 5
CORNER CORRECTION AT SCALES WITH FLINTEC LOAD CELLS........................................................... 6
CLOSING THE JUNCTION BOX....................................................................................................................... 6
SUMMARY OF IMPORTANT SERVICE HINTS................................................................................................ 7
SERVICE MATERIAL ........................................................................................................................................ 8
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
Page 3 of 8
INTRODUCTION AND TECHNICAL DATA
The Polyester junction box is designed for the parallel connection of load cells. There a re 4 different types:
Type No. of load cells Housing size Inputs Output
KPF-4 up to 4 100 x 320 x 81 mm 4x M16 or 4x M12 1x M16
KPF-6 up to 6 100 x 320 x 81 mm 6x M16 or 6x M12 1x M16
KPF-8 up to 8 100 x 320 x 81 mm 8x M16 or 8x M12 1x M16
KPF-10 up to 10 100 x 360 x 90 mm 10x M16 1x M16
The junction box type KPF is special designed for weigh bridges and silos including surge arrestors for
lightning protection. It can be connected to the instrumentation with a shielded 6-wire signal cable.
The corner correction is done with resistors. Each junction box already contains 2.1 Ohm resistors for each
load cell from the factory. Therefore it is possible to decrease a load cell signal (use a higher resistance
value) or to increase a load cell signal (use a smaller resistance value).
Housing material: Polyester
Protection class: IP66
Cable connection: With clamping terminals
Corner correction: By exchangeable resistors
Other: Over-voltage protection by surge arrestors
MECHANICAL INSTALLATION
Look for a mounting location which is more or less dry and protected from environmental stress. The junction
box itself has to be mounted with the cable glands showing vertically to the bottom. A flooding or any tensile
load on the cable glands must be prevented.
All bottom parts of the cable glands are sealed to the housing with some gaskets. You have to check the
existence and the condition of these gaskets, the gaskets have to be replaced if required.
You have to check all bottom parts of the cable glands for a firm seat in the housing.
(Recommendation: use a 12-point ring spanner with a cut-out and metric size 19 mm, if the cable are already
installed).
ELECTRICAL CONNECTIONS
2
2
1
1
2
1
121
Figure 1: Dimensions in [mm]
The earth screw (see (2) in fig.1) has to be connected to protective earth or you must establish an electrical
connection to the weigh modules for potential equalisation. For doing this only the upper nut should be
loosened and tightened again. The lower nut (= counter nut) and the earth screw with washer must not be
rotated or loosened – the gasket is bonded! If loosened by accident the earth screw must be re-inserted and
locked with some Loctite.
The connection sequence of the load cells should correspond to the corners of the scale, i.e
Corner 1 = Load cell 1, Corner 2 = Load cell 2, etc.
2
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
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LOAD CELL CABLE CONNECTION
Only the cable gland nut (see (1) in fig.1) must be loosened. The bottom part of the cable gland must remain
tightened.
It is absolute necessary to check all the bottom parts of the cable glands for a firm seat in the housing!
Then you have to feed the load cell cable through the cable gland unless the shrink tube has fully
disappeared in the box, because sealing and strain relief must be done at the cable and not at the shrink
tube.
The conductor cables have to run below the printed circuit board and will be pulled back to the top at the
upper end of the printed circuit board. Afterwards you can connect the cables to the clamping terminals as
indicated below:
Cable coulour Description Terminal designation
yellow = Cable shield yellow / gelb
red = Signal – (Output –) red / rot
white = Signal + (Output +) white /weiss
black = Excitation – (Input –) black / schwarz
(if applicable brown)* = Sense – black / schwarz
green = Excitation + (Input +) green / grün
(if applicable blue)* = Sense + green / grün
* if load cell is equiped with 6-wire conductor cable
After all conductors have been clamped to the terminals, you must tighten the cable glands. The cable must
not run sloped in the cable gland during tightening the cable gland nut.
(Recommendation: use a 12-point ring spanner with a cut-out and metric size 19 mm)
A cable gland nut is tightened correctly if the cable gland constricts the cable jacket (not the shrink tube!)
significantly!
Unused cable inlets must be closed by the delivered blind plugs. If the cable gland nuts are correctly
tightened the sealing part of the cable gland must constrict the blind plug significantly!
Please verify that all cable glands are tight and the cables are fully stress relieved.
OUTPUT CABLE CONNECTION
Only the cable gland nut (see (1) in fig.1) must be loosened. The bottom part of the cable gland must remain
tightened.
It is absolute necessary to check all the bottom parts of the cable glands for a firm seat in the housing!
The signal cable (connection between junction box and the following electronics) should be a 6 – wire
shielded cable and has to be kept as short as possible. Because this cable usually has a larger diameter than
the load cell cable, you should use the larger cable gland in the middle of the box. Depending on type and
manufacturer signal cables may have different colours. Therefore make your own choice.
Cable colour, example Description / Terminal designation
outer cable screen = Shield
pink = Signal – (Output –)
white = Signal + (Output +)
grey = Sense –
brown = Excitation – (Input –)
yellow = Sense +
green = Excitation + (Input +)
After all conductors have been clamped to the terminals, the cable gland nut must be tightened. The cable
must not run sloped in the cable gland during tightening the cable gland n ut.
(Recommendation: use a 12-point ring spanner with a cut-out and metric size 19 mm)
The cable gland nut is correctly tightened if the cable gland constricts the cable jacket (not the shrink tube!)
significantly!
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
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CORNER CORRECTION A T SCALES WITH FLINTEC LOAD CELLS
Flintec load cells are manufactured with rather tight tolerances, so in most cases an additional corner
correction is not required. The best conditions are achieved if you use load cells of the same class
(Designation is done with capital letters A to I on the load cell package besides the type label).
Hint: Corner errors can have a mechanical background, e.g. sloped mounting surface of the load cell.
Procedure:
1. Get the display value for each corner. Use the highest possible display resolution (e.g. factor 10 or
higher) or, if this is not possible, measure the the digital weight increment using corresponding weights.
2. The corner with the lowest display value is the starting point for the corner correction. The differences of
the other corners are calculated with reference to this “basic corner”.
3. Calculate the correction resistance as follows:
Deviation in [kg]
Correction resistance [Ω]
* 1100 Ω input resistance for:
400 Ω input resistance for:
=
Test weight in [kg]
BK2, SB4, SB5, SB6, SB14, SLB, ZLB, UB1, UB5, UB6, PB, RC3
RC1, SB2
Example 1: 1100 Ω load cell
0.1 kg corner error with 500 kg test load
Example 2: 400 Ω load cell
10 kg corner error with 5000 kg test load
4. Install the correction resistor into the junction box for the corresponding load cell excitation.
New resistor = Correction resistance + 2.1 Ω (pre-installed resistor)
5. Check the corners again. If required repeat the procedure.
Hint:
50 ppm resistors for corner correction are available as a set of 14 values from 0.22 Ω to 4.7 Ω (10 pcs. for
each value; article no. 5200-030).
x
0.1 kg
500 kg
10 kg
5000 kg
Input resistance of the load cell [Ω] *
x
x
1100 Ω
400 Ω
=
0.22 Ω
=
0.8 Ω
CLOSING THE JUNCTION BOX
In the junction box there are two dry tablets in a plastic bag. Unbag these pills and leave them within the
junction box .They will absorb moisture up to a certain degree.
Before you will close the junction box you must check the cover and the cover sealing for any dirt or damage.
Replace the cover sealing if required, otherwise a proper sealing is not assured.
Generally you have to use the red sealing made of silicone. You can improve the quality of this silicone
sealing (it must be the red one!) by using a suitable grease (e.g. sanitary grease for fittings).
The cover screws always have to be tightened crosswise and equally unless the cover is attached to the
junction box.
Generally the inside of the junction box must be totally dry before you can close the cover.
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
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SUMMARY OF IMPORTANT SERVICE HINTS
At each re-calibration or repair following checks or actions have to be done:
1. All bottom parts of the cable glands are sealed to the housing with some gasket. You have to check
the existence and the condition of these gaskets, the gaskets have to be replaced if required.
2. You have to check all bottom parts of the cable glands for a firm seat in the housing.
(Recommendation: use a 12-point ring spanner with a cut-out and metric size 19 mm, if the cable are
already installed).
3. All cable gland nuts must be tightened. A cable gland nut is tightened correctly if the cable gland
constricts the cable jacket (not the shrink tube!) significantly! The cables must not run sloped in the
cable glands.
4. Unused cable inlets must be closed by a blind plug. If a cable gland nut is correctly tightened the
sealing part of the cable gland must constrict the blind plug significantly!
5. An eventually existing pressure compensating valve has to be removed. The corresponding hole
must be closed by a blind plug and a gasket.
6. The earth screw must be electrically connected with protective earth (potential equalisation).
For doing this only the upper nut should be loosened and tightened again. The lower nut (= counter
nut) and the earth screw with washer must not be rotated or loosened – the gasket is bonded!
If loosened by accident the earth screw must be re-inserted and locked with some Loctite.
7. Before you will close the junction box you must check the cover and the cover sealing for any dirt or
damage. Replace the cover sealing if required, otherwise a proper sealing is not assured.
Generally you have to use the red sealing made of silicone. You can improve the quality of this
silicone sealing (it must be the red one!) by using a suitable grease (e.g. sanitary grease for fittings).
8. Before you close the cover again you have to place 2 new dry tablets within the junction box.
9. The cover screws always have to be tightened crosswise and equally unless the cover is attached to
the junction box.
10. Generally the inside of the junction box must be totally dry before you can close the cover
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
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SERVICE MATERIAL
Service kit no.1 Article no.: 5200-U1
for load cells with maximum capacity above 30 t
with ring spanner
Parts list:
Description Article no. Quantity
KP cable gland M16 x 1,5, clamping range 6.5 – 9 mm 000163 9 pcs.
Silicone cover sealing (red) 10090 1 pc.
Silicon grease, 6 g 40110 1 pc.
Dry tablet 000075 2 pcs.
Gasket 22 x 16 x 1.5 mm 4400 9 pcs.
Gasket 18 x 12 x 1.5 mm 53159 1 pc.
Round cord, 6 mm black 10101007 0.01 m
Plastic blind plug M16 x 1.5 05282 1 pc.
Plastic blind plug M12 x 1.5 00326 1 pc.
Ring spanner for M16 cable glands SSG19 1 pc.
Service kit no.2 Article no.: 5200-U2
for load cells with maximum capacity above 30 t,
like service kit no. 1 but
Service kit no.3 Article no.: 5200-U3
for load cells with maximum capacity in the range from 7.5 t to 22.5 t
with ring spanner
Parts list:
Description Article no. Quantity
KP cable gland M16 x 1,5, clamping range 4 – 6.5 mm 000917 9 pcs.
Silicone cover sealing (red) 10090 1 pc.
Silicon grease, 6 g 40110 1 pc.
Dry tablet 000075 2 pcs.
Gasket 22 x 16 x 1.5 mm 4400 9 pcs.
Gasket 18 x 12 x 1.5 mm 53159 1 pc.
Round cord, 6 mm black 10101007 0.01 m
Plastic blind plug M16 x 1.5 05282 1 pc.
Plastic blind plug M12 x 1.5 00326 1 pc.
Ring spanner for M16 cable glands SSG19 1 pc.
Service kit no.4 Article no.: 5200-U4
for load cells with maximum capacity in the range from 7.5 t to 22.5 t
like service kit no. 3 but
without ring spanner SSG19
without ring spanner SSG19
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
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