Intelligent Weighing Technology AM-3000, AM-6000, AM-15K, AM-30K Maintenance Manual

1

MAINTENANCE MANUAL

AM WEIGHING SCALE SERIES

MODELS: AM-3000, AM-6000, AM-15K, AM-30K

CONTENTS

1. INTRODUCTION

2. SPECIFICATIONS

2.1 SYSTEM BLOCK DIAGRAM

2.2 PHYSICAL LAYOUT OF ELECTRICAL CONNECTION

2.3 GENERAL SPECIFICATIONS

3. INITIAL SETUP

3.1 INTERNAL FUNCTION AND SETTING METHODS

3.2 AUTO AND DEALER CALIBRATION PROCEDURES

3.3 DISABLE CALIBRATION WITH DIP SW.(S1)

3.4 OFFSET AND SPAN VALUE DATA

3.5 FLOW CHART

4. TROUBLE SHOOTING

4.1 TROUBLE SHOOTING LOOP

4.2 PARTS AND COMPONENTS TROUBLE SHOOTING

5. ELECTRICAL CIRCUITRY

5.1 SCHEMATICS

5.2 PCB LAYOUT

6. BILL OF MATERIAL

7. APPENDIX

DECEMBER 1999 REV 1

Specifications and Function Subject to Change without Notice

2

1. INTRODUCTION

AM SERIES - ELECTRONIC WEIGHING SCALE

FEATURES:
* Full Tare
* Tare Indicator
* Zero Indicator
* Negative Value Indicator
* 2 Types of Calibration
* Dip Switch to prevent end-user calibration
* Sealable
* Bubble Level
* Adjustable Feet
* 5 1/2 x 25mm Wide Angle LCD Display
* Long Battery Operating Time
* Low -battery Indicator & Charge Indicator
* Auto Power Saving Function
* Dual Power: By Built -in Recharge

able Battery or Power Adaptor

* Platter with Stainless Steel Insert
* Optional Backlighting
* Optional Secondary Pole Mount Display
* Optional Rear Display
* Optional RS-232C Interface
* Ove rload protection against positive and negative force
* Capacity: 3kg,6kg,15kg,30kg for 1/3000 resolution

3

2. SPECIFICATION

2.1 SYSTEM BLOCK DIAGRAM

DESCRIPTION:

When a load is applied to the loa d cell. The resistance to the excitation
current in the strain gauge changes and the analog output signal varies.

It is amplified and digitalized continuously by the A/D converter into
a digital signal.

Subsequently, the resulting count is processed and managed by the CPU.
The CPU refers to the instructions from the keyboard, and then conveys
the output data to LCD driver which formats the data into a readout
for the display.

2.2 PHYSICAL LAYOUT OF ELECTRICAL CONNECTION

4

5

2.3 GENERAL SPECIFICATION

2.3.1 Overall View

2.3.2 Dimension
* Platter size: 245 x 300mm
* Overall size: 336 x 285 x 118mm

2.3.3 Model specification
Model name: AM series
Display resolution: 1/3000(3kg,6K,15kg,30kg)
Internal resolution: 1/30000
Display: Single-sided,Double-sided if request
Weight display--> 5 digits

2.3.4 Operation condition
* Power source: Rechargeable battery(6V 4Ah) or AC power
adaptor(220V/9V DC,500mA)

6

* Operating Temperature : 0¢C ~ 40¢C
* Operating Humidity : 15 ~ 85% RH
* Power Consumption : 0.1W
5W When charge

2.3.5 Main Components used
* Micro Processor : 89C51
* Crystal Oscillator : 6 MHz
* Display device : Liquid Crystal Display(LCD)
* Loadcell : 350 resistance loadcell

2.3.6 Analog Specification
* INPUT SENSITIVITY : 2mV/V(C2G1 TYPE LOAD CELL)
* ZERO ADJUST RANGE : 2% R.O.
* ZERO BALANCE RANGE : +/-10% R.O.
* L/C APPLIED VOLTAGE : DC 3.3V
* SPEED OF A/D CONVERSION : 10 times/sec
* INTERNAL RESOLUTION : 30000

2.3.7 Model VS. Capacity & division

MODEL NO. CAPACITY EXTERNAL DIVISION
1/3000
AM-3000 3kg 1g
AM-6000 6kg 2g
AM-15K 15kg 5g
AM-30K 30kg 10g

7

3. INITIAL SETUP

3.1 INTERNAL FUNCTIONS AND SETTING METHODS

INTERNAL FUNCTION TABLE

Function Symbol Description
1 F.1 Span value reading and dealer calibration
2 F.2 Full display segment and max. capacity check
3 F.3 Check offset value and scale configuration
4 F.4 Auto power off setting

HOW TO ENTER THE REQUIRED FUNCTION MODE
a. Turn scale off.
b. Press and hold TARE, then turn scale on. Scale display F.1
c. Press TARE until the required function number appears.
d. Press MODE
e. Press MODE until the required setting appears.
f. Press TARE to confirm.
g. Repeat step c to f for other function setting, or

h. Press ON/ZERO to save settings and return to normal

operation.

F.1 Span Value Reading and Dealer Calibration
a. Simply enter F.1 to read the A/D counts.

b. Press ON/ZERO to clear t

he A/D counts, apply test mass

onto platter, the span value of test mass will be
displayed.

c. Refer to Dealer Calibration procedures for dealer

calibration.

F.2 Display Segment and Rated Capacity & Division Check
When funtion is entered, all segment will be displayed.

Check and make sure that no segments are missed.

F.3 Total Internal Count Checking and Scale Configuration
1 Enter F.3, scale displays the Offset Value when unloaded.

2 Apply extra load onto platter, the total internal count

value will be displayed.
SELECT WEIGHT UNITS

1 Press and hold MODE until the weight unit appears.
2 To employ all(metric and pound) weight units, press
MODE until lb appears. To disable pound weight unit,
press MODE until kg appears.
3 Press ON/ZERO to save setting and back to normal operation
status.

8

F.4 Auto Power Off Setting
Two modes are available: (Default=4_OFF)

0._OFF = Auto Power Off function is disabled.

4._OFF = Scale will automatically be turned off after
4 minutes unused.

3.2 AUTO AND DEALER CALIBRATION PROCEDURES

ACCEPTABLE LOAD FOR AUTO AND DEALER CALIBRATION

Model
Number

External
Division

Acceptable Auto and Dealer

Calibration Load
AM-3000 1/3000 1kg 2kg
AM-6000 1/3000 2kg 4kg
AM-15K 1/3000 5kg 10kg
AM-30K 1/3000 10kg 20kg

Dealer Calibration Procedures:

1 Turn scale off.
2 Press and hold TARE, then turn scale on.
3 Scale displays F.1
4 Press MODE
5 Scale displays offset value
6 Press ON/ZERO
7 Press TARE
8 Press ON/ZERO
9 Press TARE

10

Press ON/ZERO, scale displays a circle at the right hand

of the

display. It means the scale is ready for dealer

calibration.
11 Make sure that the figure being displayed is =0 or 1,

If not, press ZERO again.
12 Load calibration either load as listed on above table.
13 When value displayed is stable, press MODE.
14 Wait until the scale starts count down.
15 Calibration completed and scale is ready for operation.

9

Auto Calibration Procedures:

1 Turn scale off
2 Press and hold MODE, then turn scale on.
3 Scale displays CAL?
4 Press MODE
5 Scale displays LOAD XXXX or XXXX
6 Load calibration load according to above table.
7 Wait until the scale display DONE and starts count down.
8 Calibration completed and scale is ready for operation.

3.3 DISABLE CALIBRATION WITH DIP SW.(S1)

The DIP SW.#1 is used to control calibration. Push this switch
to ON position to disable calibration.

3.4 OFFSET AND SPAN VALUE DATA

OFFSET AND SPAN VALUE DATA TABLE

Model
Number

Offset
Value
(Thousand)

Span Value(Thousand) at

Various Load Applied

Offset
Control

Span Control(Ohm)
R1A

AM-3000 10~14

10~15 at
1kg

20~30 at
2kg

VR1 Trimmer 35K

AM-6000 10~14 10~15 at

2kg

20~30 at
4kg

VR1 Trimmer 23.2K

AM-15K 10~14 10-15 at

5kg

20-30 at 10kg VR1 Trimmer 25K

AM-30K 10-14 10~15 at

10kg

20~30 at 20kg VR1 Trimmer 15K

READING OFFSET VALUE
1 Turn scale off
2 Remove all load from platter
3 Enter F.3 and read the offset value

READING SPAN VALUE
1 Turn scale off
2 Remove all load from platter
3 Enter F.1
4 Press ZERO
5 Apply load to platter. Span value according to load
applied will be displayed.

HOW TO ADJUST OFFSET VALUE
In case the offset value is out of range, adjust the trimmer
located at VR1 on the mainboard to obtain correct offset value.

10

HOW TO ADJUST SPAN VALUE
The span value is controlled by resistor located on R1A, standard
resistor value of R1A is listed on the above table. If the
required span value is not attained, then change R1A resistor
according to either case below:

Span value too low : Increase the resistance of R1A.
Span value too high : Decrease the resistance of R1A.

11

3.5 FLOW CHART

3.5.1 Auto Calibration(for end-user)

12

3.5.2 Function Test(for technicians only)

13