Adam CBC-M Series User manual

.
Adam Equipment
CBC-M SERIES
Service Manual
Software rev.: 3.06A & above
ADAM EQUIPMENT CO. LTD.
P.N. 8227, Rev. B5, October 2007
© Adam Equipment Company 2007

© Adam Equipment Company 2007

© Adam Equipment Company 2007 1
CONTENTS
1.0 INTRODUCTION.......................................................................................................2
2.0 SPECIFICATIONS....................................................................................................3
3.0 TROUBLESHOOTING..............................................................................................4
4.0 ERROR CODES .......................................................................................................5
5.0 CBC-M DESCRIPTION.............................................................................................6
6.0 LOAD CELL DAMAGE..............................................................................................6
7.0 CALIBRATION..........................................................................................................9
7.1 CALIBRATION PROCEDURE...............................................................................9
7.2 SECURITY SEALS..............................................................................................10
7.3 CALIBRATION PROCEDURE.............................................................................10
8.0 SERVICE PARAMETERS.......................................................................................11
8.1 USING “0000” TO ENTER THE CALIBRATION PARAMETER............................11
8.2 USING “2006” TO ENTER THE SERVICE PARAMETERS..................................12
8.2.1 F1 -CALIBRATION............................................................................................12
8.2.2 F2 -RESOLUTION ............................................................................................13
8.2.3 F3 –CAPACITY................................................................................................13
8.2.4 F4 -INITIAL ZERO RANGE ...............................................................................14
8.2.5 F5 -RE-ZERO RANGE......................................................................................14
8.2.6 F6 -SUCCESSIVE TARE..................................................................................14
8.2.7 F7 -A/D COUNT.................................................................................................15
8.2.8 F8 –ZERO.........................................................................................................15
8.2.9 F9 –PIN.............................................................................................................15
8.2.10 F10 –LOW VOLTAGE DETECTION..................................................................16
9.0 WIRING DIAGRAM.................................................................................................17
10.0 MECHANICAL ASSEMBLY ....................................................................................18
10.1 LIST OF MECHANICAL ASSEMBLY...................................................................19
11.0 DISPLAY ASSEMBLY.............................................................................................20
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1.0 INTRODUCTION
•The CBC-M series of scales provide an accurate, fast and versatile counting
and check-weighing scales.
•CBC-M scales are kilogram only scales
•There are 4 models of approved scales with capacities up to 30kg.
•They all have stainless steel weighing platforms on an ABS base assembly.
•All scales are supplied with a RS-232 bi-directional interface and real time
clock (RTC)
•All scales have sealed keypad with colour coded membrane switches and
there are three large, easy to read liquid crystal type displays (LCD). The
LCD’s are supplied with a backlight.
•The scales include automatic zero tracking, audible alarm for pre-set
weights, automatic tare, an accumulation facility that allows the count to be
stored and recalled as an accumulated total.
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© Adam Equipment Company 2007 3
2.0 SPECIFICATIONS
CBC-M SERIES
Model CBC 3M CBC 6M CBC 15M CBC 30M
Maximum
Capacity 3 kg 6 kg 15 kg 30 kg
Readability 0.001 kg 0.002 kg 0.005 kg 0.01 kg
Tare Range -3 kg -6 kg -10 kg -30 kg
Repeatability
(Std Dev) 0.001 kg 0.002 kg 0.005 kg
0.01 kg
Linearity ± 0.002 kg 0.004 kg 0.01 kg
0.02 kg
Common Specifications
Stabilisation
Time 2 Seconds typical
Operating
Temperature 0°C - 40°C
32°F - 104°F
Power supply 230 VAC 50/60 Hz.
120 VAC available.
Battery Internal rechargeable battery
(~90 hours operation)
Calibration Not available
Display 3 x 6 digits LCD digital displays
Balance
Housing ABS Plastic, Stainless Steel platform
Pan Size 225 x 275mm
8.9” x 10.8”
Overall
Dimensions
(wxdxh)
315 x 355 x 110mm
12.4” x 14” x 4.3”
Net Weight 4.1 kg / 9 lb
Applications Counting Scales
Functions Parts counting, weighing, accumulating memory,
pre-set count with alarm
Interface RS-232 bi-directional interface
Date/Time Real Time Clock (RTC),
To print date and time information.
(Dates in year/month/day, day/month/year or
month/day/year formats- Battery backed)

© Adam Equipment Company 2007 4
3.0 TROUBLESHOOTING
1. Unit does not
turn on Check whether the scale is plugged into the power supply properly.
Check the operation of the charging circuit.
Check whether the battery is charged- LED should turn to green from red.
Check the adapter output.
.
2. The scale
weighs but is
unstable
Air drafts or vibration or unstable table.
Pan rubbing against case or not installed correctly.
Scale not installed properly.
Improper connections on ADC circuit.
3. Scale shows
wrong weight Scale not installed correctly.
Check the Calibration.
To check whether a part of product weighed is trapped between the pan
and the scale.
Incorrect adjustment of the mechanical stops.
4. An error “E4”
displays on
the screen
Load cell damage.
Scale not installed properly.
Incorrect adjustment of the mechanical stops.
Factory calibration has been tampered with- check the ADC counts and
re-calibrate.

© Adam Equipment Company 2007 5
4.0 ERROR CODES
ERROR CODE DESCRIPTION POSSIBLE CAUSES
Err 4 Initial Zero is greater than
allowed (4% of maximum
capacity) when power is turned
on or when the [Zero/Enter] key
is pressed.
Weight on the pan when turning
the scale on.
Excessive weight on the pan when
zeroing the scale.
Improper calibration of the scale.
Damaged load cell.
Damaged Electronics.
Err5 Keyboard error. Improper operation of the scale.
Err6 A/D count is not correct when
turning the scale on. Platform is not installed.
Load cell is damaged.
Electronics is damaged.
Err7 Scale is not stable when setting
the percentage weighing. The scale is not stable.
Improper operation of the scale.
FAILHor FAILL Calibration error. Improper calibration (should be
within +10% of the factory
calibration). The old calibration
data will be retained until the
calibration process is complete.
Err9 Scale is unstable. There is vibration or draft making
the scale unstable.
Electronics may be damaged.

© Adam Equipment Company 2007 6
5.0 CBC-M DESCRIPTION
The CBC-M scales have an enclosure with all components mounted within it. To gain
access to the components remove the 5 screws securing the cover to the base.
The basic unit consists of:
9Base
9Load Cell frame
9Power switch
9Main PCB assembly
9Battery
9Display PCB assembly
9Keypad
All models of CBC-M are similar except the selection of load cells and the program.
Normally if a problem is found with a circuit board the most cost effective method of
solving the problem is to replace the circuit board.
The main PCB assembly includes:
9A/D converter (AU1),
9Microprocessor (DU1) and
9Power supply/battery charger circuits (DU5, T2).
6.0 LOAD CELL DAMAGE
The most common reason a scale fails is that the load cell has been damaged. The
damage can be from 2 primary causes. The first is physical damage due to an overload or
an impact from the side and the second is damage due to the environment, such as
moisture, extreme heat or a cut cable if the cables are exposed.
PRINCIPLE OF OPERATION
The stain gauge load cell is a method of measuring the amount of stress put onto a metal
structure due to a weight being supported by the structure. The stress is measured using
4 strain gage sensors mounted in a particular way on the metal structure.
These 4 strain gauges are connected in such a way that they form a wheatstone bridge.
See figure below. In the simplest load cells there are only the 4 resistances of the strain

gages to consider. Normally without a load on the load cell all the resistances are the
same. However when the load cell has a weight on it 2 of the strain gages will be in
compression (A and D) and the resistance will decrease and 2 will be in tension (B and C)
and their resistance will increase.
350 ohm
350 ohm
350ohm
350ohm
AB
CD
+E
-S
-E
+S
BALANCED BRIDGE
10 VOLT POWER
SUPPLY
Vout = O VOLTS,
BETWEEN +S AND -s
351ohm
349ohm
351ohm
349ohm
AB
CD
+E
-S
-E
+S
UNBALANCED BRIDGE
FULL CAPACITY LOAD
ON THE LOAD CELL
10 VOLT POWER
SUPPLY
Vout = 0.028 VOLTS (28mv),
BETWEEN +S AND -s
This will cause the bridge to become unbalanced. When the bridge has a voltage across it
from +E to -E then the signal output at +S and -S will show a voltage of zero volts with no
load and a small voltage proportional to the load as the load is increased. Typical load
cells show 20-30mv of signal if the excitation voltage is 10volts and the load cell is fully
loaded.
Most load cells used in scales are not as simple as this example. They have additional
resistance elements added to compensate for temperature variations and to set the
outputs to correct voltages. The circuit of a typical load cell is shown below-
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© Adam Equipment Company 2007 8
A method to check the basic function and integrity of a load cell can be done using a
ohmmeter and voltmeter with up to a 10volt power supply.
Before the load cell is connected to the power supply use the ohmmeter to measure the
resistance between the wires. Typical resistance values are:
+E to -E 410 ohms ±30 ohms
+S to -S 350 ohms ± 2 ohms
+E to +S or any other combination similar approximately 270 ohms.
If the load cell has Sense connections in addition they are connected to the excitation
internal to the load cell.
Connect the load cell +E and -E to a power supply, typically 10 volts. Never use more
than 12 volts as it may damage the load cell.
Measure the voltage between +S and -S.
With no load the voltage should be approximate 0mv ±3mv.
With a mass on the load cell the output voltage should increase. The amount by which it
increases will be dependent upon the sensitivity of the load cell, capacity of the load cell,
the excitation voltage and the amount of mass placed on the load cell. Most load cells
have a sensitivity of either 2mv/V or 3mv/V.
The expected change to the output is:
Vout = (2mv/V) * Vext * Mass
capacity of load cell
For example a 2mv/V load cell of 30Kg capacity with 20Kg placed on it. Vext is 5 volts
would give a output of approximately:
Vout =
(2mv/V) * Vext * Mass = 2mv/V * 5V * 20Kg = 6.7mv
capacity of load cell 30kg
If the load cell has been damaged the no load voltage will likely be greater than 3mv or the
loaded voltage will be grossly different from the expected value. Remember the loaded
voltage will be offset by the amount of zero load voltage measured.