QHW series
Digital Weighing Scales
User’s guide
UGQHW-E0204
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Contents
SECTION 1 INTRODUCTION………………………………………………………………1
SECTION 2 SPECIFICATIONS……………………………………………………..……2
SECTION 3 INSTALLATION……………………………………………………..……….3
3.1 General Installation……………………………………………………………………3
3.2 Install of QHW series…………………………………………………………..………3
SECTION 4 KEY DESCRIPTIONS………………………………………………………4
SECTION 5 DISPLAYS………………………………………………………………….5
SECTION 6 OPERATION…………………………………………………………….…..6
6.1 Zeroing the display…………………………………………………………………….6
6.2 Taring……………………………………………………………………………..…….6
6.3 Weighing a sample……………………………………………………………..…….6
6.4 Percent weighing………………………………………………………………..…….6
6.5 Parts counting……………………………………………………………………..…….7
6.6 Check-weighing………..………………………………………………………..…….7
6.7 Accumulated total………..………………………………………………………..…….8
6.8 Manual accumulation………..…………………………………………………..…….8
6.9 Automatic accumulation……..………………………………………………..…….9
SECTION 7 BATTERY OPERATION………………………………………………..…10
SECTION 8 RS-232 OUTPUT…………………………………………………………..11
SECTION 9 PARAMETERS……………………………………………………………12
SECTION 10 CALIBRATION……………………………………………………..……..13
SECTION 11 ERROR CODES…………………………………………………………15
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SECTION 1 INTRODUCTION
The QHW series of scales provides an accurate, fast and versatile series of general
purpose weighing scales with counting, % weighing and check-weighing functions.
There are 4 models in each series, with capacities up to 30 kg.
They all have stainless steel weighing platforms on an ABS base assembly.
All the keypads are sealed, color coded membrane switches and the displays are
large easy to read liquid crystal type displays (LCD). The LCD’s are supplied with a
backlight.
All units include automatic zero tracking, audible alarm for pre-set weights, automatic
tare, pre-set tare and an accumulation facility that allows the count to be stored and
recalled as an accumulated total.
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QHW digital weighing scales user’s guide
SECTION 2 SPECIFICATIONS
QHW SERIES
QHW 15
15kg
0.5
1:30000
-10kg
10g
QHW 30
30kg
1g
1:30000
-30kg
20g
Model #
Maximum Capacity
Readability
Resolution
Tare Range
Minimum Capacity
Repeatability (Std Dev)
Linearity ±
QHW 3
3kg
QHW 6
6kg
0.1g
1:30000
-3kg
2g
0.2
1:30000
-6kg
4g
0.1
0.2
0.5g
1g
1g
2g
0.2g
0.4
Units of Measure
kg, g, Lb., oz.
Common Specifications
Interface
RS-232 Output Optional
2 Seconds typical
0°C - 40°C / 32°F - 104°F
115 / 230 Vac, 50/60Hz, 10 watts
Automatic External
Stabilisation Time
Operating Temperature
Power supply (external)
Calibration
Display
Draft shield
6 digits LCD digital display
N/A
Balance Housing
Pan Size
Overall Dimensions (wxdxh)
Gross Weight
ABS Plastic, Stainless Steel platform
225 x 300mm / 8.9 x 11.8”
320 x 340 x 125mm / 12.6 x 13.4 x 4.9”
3.8kg/8.4lb
Applications
General Purpose Scale
Functions
Other Features and Specs
Weighing, parts counting, % weight, Check weighing,
Internal rechargeable battery (~70 hours operation)
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SECTION 3 INSTALLATION
3.1 GENERAL INSTALLATION
The scales should be sited in a location that will not degrade the accuracy.
Avoid extremes of temperature. Do not place in direct sunlight or near air conditioning
vents.
Avoid unsuitable tables. The tables or floor must be rigid and not vibrate. Do not
place near vibrating machinery.
Avoid unstable power sources. Do not use near large users of electricity such as
welding equipment or large motors.
Avoid high humidity that might cause condensation. Avoid direct contact with water.
Do not spray or immerse the scales in water.
Avoid air movement such as from fans or opening doors. Do not place near open
windows.
Keep the scales clean.
Do not stack material on the scales when they are not in use.
3.2 INSTALLATION of QHW SERIES
The QHW Series comes with a stainless steel platform packed separately. Place the
platform in the locating holes on the top cover. Do not press with excessive force as
this could damage the load cell inside.
Level the scale by adjusting the four feet. The scale should be adjusted such that the
bubble in the spirit level is in the centre of the level and the scale is supported by all
four feet, If the scale rocks readjust the feet.
Attach the mains cable to the connector on the bottom of the scale. The power switch
is located on the base near the front of the scale.
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QHW digital weighing scales user’s guide
SECTION 4 KEY DESCRIPTIONS
Zero or
Set the zero point for all subsequent weighing. The display shows zero.
A secondary function
functions.
, of "Enter" key when setting parameters or other
Tare or
Tares the scale. Stores the current weight in memory as a tare value, subtracts the
tare value from the weight and shows the results. This is the net weight. Entering a
value using the keypad will store that value as the tare value.
A secondary function
, of incrementing the active digit when setting a value for
parameters or other functions.
Lim or
Sets the limits for check weighing. Allows setting of either the low limit or the high
limit or both.
Secondary function
, is to move the active digit to the right when setting values
for parameters or other functions.
%
Enters the percent weighing function. Allows the weight, unit weight, and count to
be seen when parts counting.
Secondary function
, is to move the active digit to the left when setting values for
parameters or other functions.
Func or
Used to select the function of the scale. If the scale is weighing it will select parts
counting. Of it is not in weighing mode it will return the user to weighing.
Secondary function ( C ) , is to act as a clear key when setting values for parameters
or other functions.
Print or
To print the results to a PC or printer using the optional RS-232 interface. It also
adds the value to the accumulation memory if the accumulation function is not
automatic.
Secondary function (ESC) , is to return to normal operation when the scale is in a
parameter setting mode.
U key
This key will select either kilograms、 pounds、 ounce、g and t for the weighing unit.
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SECTION 5 DISPLAYS
The LCD display will show a value and a unit to the right of the digits.
In addition there are labels for TARE, GROSS weight, ZERO
battery
and for Low
Low Battery Symbol
Parts Counting Units
Stability Symbol
g/pcs
oz %
HI
GROSS
TARE
OK
888888
ZERO
LO
tkglb
Checkweighing Symbols
Weighing Units
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QHW digital weighing scales user’s guide
SECTION 6 OPERATION
6.1 ZEROING THE DISPLAY
You can press the ZERO/ENTER key at any time to set the zero point from which all
other weighing and counting is measured, within 4% of power up zero. This will
usually only be necessary when the platform is empty. When the zero point is
obtained the display will show the indicator for zero.
The scale has an automatic rezeroing function to account for minor drifting or
accumulation of material on the platform. However you may need to press the
ZERO/ENTER key to rezero the scale if small amounts of weight are shown when the
platform is empty.
6.2 TARING
Zero the scale by pressing the ZERO/ENTER key if necessary. The zero indicator will
be on.
Place a container on the platform, a value for its weight will be displayed.
Press the TARE key to tare the scale. The weight that was displayed is stored as the
tare value and that value is subtracted from the display, leaving zero on the display.
The "TARE" indicator will be on. As product is added only the weight of the product
will be shown. The scale could be tared a second time if another type of product was
to be added to the first one. Again only the weight that is added after taring will be
displayed.
When the container is removed a negative value will be shown. If the scale was tared
just before removing the container this value is the gross weight of the container plus
all product that was removed. The zero indicator will also be on because the platform
is back to the same condition it was when the ZERO/ENTER key was last pressed.
6.3 WEIGHING A SAMPLE
To determine the weight of a sample first tare the empty container then place the
sample in the container. The display will show the weight and the units of weight
currently in use.
6.4 PERCENT WEIGHING
The scale will allow a sample weight to be shown as 100%. Then any other weight
placed on the scale will be displayed as a percentage of the original sample. For
example is 350g is placed on the scale and the % key is pressed the display will
show 100.00%.
Removing the 350g weight and putting a 300g weight on the scale the display will
show 85.71% as 300g is 85.71% of 350g.
Note: the scale may jump by large numbers unexpectedly if small weights are used to
set the 100% level.
For example if only 23.5g is on a scale with 0.5g increments
and the scale is set to 100%, the display will show 100.00%, however a small change
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of weight will cause the display to jump to 102.13% as one scale division (0.5g)
increase to 24.0g will be equivalent to a 2.13% increase.
Removing the 350g weight and putting a 300g weight on the scale the display will
show 85.71% as 300g is 85.71% of 350g.
Pressing the FUNC key will return the scale to weighing.
6.5 PARTS COUNTING
When the scale is showing weight, pressing the FUNC key will start the parts
counting function.
Before beginning, tare the weight of any container that will be used, leaving the
empty container on the scale. Place the number of samples on the scale. The
number should match the options for parts counting, 10, 20, 50, 100 or 200 pieces.
Press the FUNC key to begin. The scale will show "SP 10" asking for a sample
size of 10 parts. Change the sample size by pressing the TARE/Ï key. the display
will cycle through the options: 10,20, 50, 100, 200 and back to 10.
Press the ZERO/ENTER key when the number matches the number of parts used for
the sample. As more weight is added the display will show the number of parts
(pcs).
Press the % key to display unit weight (g/pcs), Total weight (kg) or the count (pcs).
Press the FUNC key to return to normal weighing.
6.6 CHECK-WEIGHING
Check-weighing is a procedure to cause an alarm to sound when the weight on
the scale meets or exceeds values stored in memory. The memory holds values
for a high limit and a low limit. Either limit can be used or both can be used.
Press the LIMIT key. The display will show the current High Limit with the left most
digit flashing and the HI symbol on to the left of the display..
To change the value shown use the %/Í and the LIMIT/Î to select the digit to
change. Then use the TARE/Ï key to increment the flashing digit. When the
desired value is shown press the ZERO/ENTER key to accept the value. If you
want to reset the value to zero press the FUNC/C key to clear the value.
After pressing the ZERO/ENTER key the display will then show the Low Limit, the LO
symbol will be on to the left side of the display.
Enter the low limit in the same way the high limit was entered.
After pressing the ZERO/ENTER key the scale will return to weighing with the
Check-weighing function enabled.
When a weight is placed on the scale the arrows will show if the weight is above or
below the limits and the beeper will sound as described below.
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QHW digital weighing scales user’s guide
BOTH LIMITS SET
The display will show OK and the beeper will sound when the weight is
between the limits.
LOW LIMIT SET,
HIGH LIMIT is set to zero
The display will show OK and the beeper will sound when the weight is
less than the Low Limit. Above the Low Limit the display will show
HIGH and the beeper will be off.
HIGH LIMIT SET,
LOW LIMIT is set to zero
The display will show LOW and the beeper will be off when the weight
is less than the High Limit. Above the High Limit the display will show
OK and the beeper will be on.
BOTH LIMITS SET.
LOW IS SET GREATER THAN HIGH
The beeper will never sound and the display will show LOW if the
weight is less that the LOW limit, and HIGH if the weight is greater than
the Low Limit.
NOTE: The weight must be greater than 20 scale divisions for the check weighing to
operate.
To disable the Check-Weighing function enter zero into both limits by pressing the
FUNC/C key when the current limits are shown then pressing the ZERO/ENTER key
to store the zero values.
6.7 ACCUMULATED TOTAL
The scale can be set to accumulate automatically when a weight is added to he scale
or manually by pressing the PRINT key.
See the PARAMETERS Section for
details of selecting the method. The accumulation function is only available when
weighing. It is disabled during percent weighing or parts counting.
6.8 MANUAL ACCUMULATION
When the scale is set to manual accumulation the weight displayed will be stored in
memory when the PRINT key is pressed and the weight is stable.
The display will show "ACC 1" and then the total in memory for 2 seconds before
returning to normal. If the optional RS-232 interface is installed the weight will be
output to a printer or PC.
Remove the weight, allowing the scale to return to zero and put a second weight on.
Press PRINT, the display will show "ACC 2" and then show the new total.
Continue until all weights have been added.
To view the totals in memory press the PRINT key when the scale is at zero. The
display will show the total number of items "ACC xx" and the total weight before
returning to zero.
The totals will also be printed via the RS-232 interface.
To erase the memory press PRINT to view the totals and then press the FUNC/C key
to clear the memory.
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6.9 AUTOMATIC ACCUMULATION
When the scale has been set to Automatic Accumulation the value is stored in
memory automatically.
Add a weight to the scale, the beeper will sound when the scale is stable to signify
the value is accepted. Remove the weight.
The display will show "ACC 1" and the totals in memory when the scale returns to
zero.
Adding a second weight will repeat the process.
While the weight is on the scale it is permissible to press the PRINT key to store the
value immediately. In this case the scale will not store the value when the weight is
removed.
The totals can be viewed as above.
In all cases the scale must return to zero or a negative number before another
sample can be added to the memory.
More product can then be added and PRINT pressed again. This can continue for up
to 99 entries, or until the capacity weight display is exceeded.
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QHW digital weighing scales user’s guide
SECTION 7 BATTERY OPERATION
The scales can be operated from the battery if desired. The battery life is
approximately 100 hours.
When the battery needs charging the arrow above the low battery symbol under the
weight display will turn on. The battery should be charged as soon as the arrow
above the symbol is on. The scale will still operate for about 10 hours after which it
will automatically switch off to protect the battery.
To charge the battery simply plug into the mains power. The scale does not need to
be turned on.
The battery should be charged for 12 hours for full capacity.
Just under the quantity display is an LED to indicate the status of battery charging.
When the scale is plugged into the mains power the internal battery will be charged.
If the LED is green the battery has a full charge. If it is Red the battery is nearly
discharged and yellow indicates the battery is being charged.
As the battery is used it may fail to hold a full charge. If the battery life becomes
unacceptable then contact your distributor .
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SECTION 8 RS-232 OUTPUT
The QHW Series of scales can be ordered with an optional RS-232 output.
Specifications:
RS-232 output of weighing data
ASCII code
4800 Baud
8 data bits
No Parity
Connector: 9 pin d-subminiature socket
Pin 2
Output
Pin 3 Input, not used at this time
Pin 5 Signal Ground
Data Format for normal weighing operations, parts counting or recalling of totals from
memory will all be different. Examples follow:
Normal Output
GS
1.234kg
GS for Gross weight, NT for net weight and a unit of
weight
No..
1
This number increments every time a new value is
stored in memory
Total 1.234kg
<lf>
<lf>
The total value stored in memory
Includes 2 line feeds
When percent weighing the output is the weight shown in percent only.
GS
<lf>
<lf>
100.00%
GS for Gross weight, NT for net weight and a unit of weight
Includes 2 line feeds
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QHW digital weighing scales user’s guide
SECTION 9 PARAMETERS
The scale has 6 parameters that can be set by the user. These allow the user to set
the scale to:
• Display the weight in other increments of weight to minimize the affects of
vibration, wind or other environmental conditions.
• Control the back light on the display. It may be necessary to turn the backlight
off to maximize battery life.
• Set the Accumulation to Automatic, manual or set the RS-232 interface to
continuously print the weight.
• Set whether accumulation when print
• Set auto zero range
• Select another weighing unit than the standard.
To set parameters press the FUNC and PRINT keys at the same time.
The display will show "Inc xx" The first value shown is the default scale increment
value. To select a different increment value press the TARE/Ï key to change the
value then press the ZERO/ENTER key.
For example on a 15kg scale the standard increment is 0.5g, the value can be
changed to 1.0g or 2.0g.
The next parameter is control of the backlight. The standard is to have the backlight
operate automatically, turning off when the scale is not used. The backlight can be
set to be "EL On" , "EL Au" (Automatic) or "EL Off". The maximum battery life
is achieved with the backlight turned off.
Press the TARE/Ï key to change the value then press the ZERO/ENTER key.
Automatic accumulation is next. With "Au On" the memory will accumulate the
weight automatically, "Au Off" will enable the manual accumulation and with "P
Cont" set the RS-232 interface will send the weight continuously and the
accumulation function is disabled.
Press the TARE/Ï key to change the value then press the ZERO/ENTER key.
Whether accumulation when print is next, With “ACC ON” when you print it will
accumulation, “ACC OF” will only print without accumulation.
Press the TARE/Ï key to change the setting then press the ZERO/ENTER key.
Auto zero range is next, you can select 0.5d, 1d, 2d and 4d.
Press the TARE/Ï key to change the setting then press the ZERO/ENTER key.
The displayed unit of weight is set next. The scales are normally calibrated and
display in kilograms, however they will show the weight in grams, ounces or pounds
and selected by this function.
Press the TARE/Ï key to change the value then press the ZERO/ENTER key.
When the scales are set to display in other units of weight the accumulation function
is still keeping the weight in kilograms.
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SECTION 10 CALIBRATION
10.1 Linear calibrate
To start calibration turn the scale off and then turn it back on. Press the limit and %
keys together during the initial counting from 9 to 0 on the display.
The display will show "unLoAd". Remove all weight from the pan and then press the
ZERO/ENTER key to set the initial zero point.
The display will then show the first calibration weight request. Put this weight on the
platform and then press the ZERO/ENTER key when stable. The scale should be
stable before pressing the ZERO/ENTER key to accept a weight. The stability
indicator will turn on to show the value is stable.
After all calibrate weight completed, press ZERO/ENTER to complete the calibration.
The scale will begin counting back to zero after the last weight has been selected.
Calibration weights
QHW SERIES
Model #
Weight 1
Weight 2
Weight 3
QHW 3
zero
1000g
3000g
QHW 6
zero
2kg
QHW 15
zero
5kg
15kg
QHW 30
zero
10kg
6kg
30kg
10.2 Normal calibrate
To start calibration turn the scale off and then turn it back on. Press the Tare and %
keys together during the initial counting from 9 to 0 on the display.
The display will show "unLoAd". Remove all weight from the pan and then press the
ZERO/ENTER key to set the initial zero point.
Then use %, Limit and Tare key to key in calibrate weight, press Zero key to sure,
display shows “load”, put this weight on platter, after stable indicator on, press Zero
key to sure.
After selfchecking again, QHW is ready for you.
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QHW digital weighing scales user’s guide
SECTION 11 ERROR CODES
During the initial power-on testing or during operation it is possible the scale may
show an error message. The meaning of the error messages is described below.
If an error message is shown repeat the procedure that caused the message, turning
the balance on, calibration or other functions. If the error message still is shown
then contact your dealer for further support.
ERROR CODE DESCRIPTION
POSSIBLE CAUSES
Err 4
Initial Zero is greater than Weight on the pan when turning the
allowed (4% of maximum scale on.
capacity) when power is Excessive weight on the pan when
turned on or when the zeroing the scale.
ZERO/ENTER
pressed,
key
is Improper calibration of the scale.
Damaged load cell.
Damaged Electronics.
Err 5
Err 6
Keyboard Error.
A/D count is not correct Platform not installed.
Improper operation of the scale.
when turning the scale on.
Load cell damaged.
Electronics damaged.
To view the A/D count press the ZERO/ENTER key and the % key at the same time
while the scale is performing the initial check at power-on. Press ZERO/ENTER to
return to normal.
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