NCI 7620U User manual

User’s Manual
Model 7620U
Bench Scale

Model 7620U Bench Scale User’s Manual
2
Risk of electrical shock. Do not remove cover. No user serviceable
parts inside. Refer servicing to qualified service personnel.
Weigh-Tronix reserves the right to change
specifications at any time.
CAUTION
10/23/03 7620U_U.P65 PN 7424-16232E e1 Printed in USA

Model 7620U Bench Scale User’s Manual 3
Specifications ..................................................... 4
Initial Setup ......................................................... 7
Operation ............................................................ 8
7620U Menu Structure...................................... 11
Diagnostics Mode ............................................. 12
Configuration Mode .......................................... 15
Calibration Mode .............................................. 17
Gravity Mode .................................................... 19
Review Scale Settings ...................................... 20
Communications ............................................... 21
Error Codes ...................................................... 23
Troubleshooting ................................................ 24
Spare Parts Listing ........................................... 27
Table of Contents

Model 7620U Bench Scale User’s Manual
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Specifications
7620-30 (6-30)
0-6 kg x 0.001 kg n1=6000 d
6-30 kg x 0.005 kg n2=6000 d
7620-30 (5-30)
0-5 kg x 0.001 kg n1= 5000 d
5-30 kg x 0.005 kg n2= 6000 d
7620-35(6-35)
0-6 kg x 0.001 kg n1=6000 d
6-35 kg x 0.01 kg n2=3500 d
7620-50
0-5 kg x 0.005 kg n1=1000 d
5-50 kg x 0.01 kg n2=5000 d
The Model 7620 is approved as legal for trade:
United States - NTEP COC #95-071
Canada - Ministry of Industry #AM 5074
Europe – EEC (OIML) #UK 2476
For use as a Class III device from +5ºC to 40ºC
356 mm L x 318 mm W x 104 mm H
14" L x 12.5" W x 4.2" H
UL/CSA and CE approved inline power supply
with universal adapter pigtail.
Input: 230 VAC + 10% -15%
Output: 15 VDC @ .3 Amps
50 (±3) Hz Standard
Capacity/Resolution
Agency Certificates
of Conformance
Dimensions
Power Supply
Frequency

Model 7620U Bench Scale User’s Manual 5
Power Requirements
Operating Temperature
Construction
Overload Protection
Display
Scale Leveling
Zero Window
Under Capacity Limits
Over Capacity Limits
Sealing
0.1 amp maximum
+5º C to + 40º C
10% to 95% RH (non-condensing)
Die cast aluminum base and load bridge.
Plastic ABS weigh platter
Aluminum quartz digital load cell
Adjustable center stop
Fixed corner stops
400% static loading
200% dynamic loading
13mm (0.5") high seven-digit LCD
Key panel with ZERO and F1 function keys
Optional remote display with 2m (7ft) cable
Level bubble under weigh platter
Adjustable feet in each corner
Automatic zero setting is ±10% of maximum
capacity—active at power up. Manual zero
setting range is ± 2% of maximum capacity—
active using the ZERO key.
Under capacity indication will be given with
dashes appearing on the bottom line of the
display whenever the display is more than 2
percent below the initial zero value.
Over capacity indication will be given with dashes
appearing in the upper line of the display when-
ever the weighed item exceeds 9 divisions over
the rated capacity of the unit. The scale will use
the initial zero value for reference for over
capacity determination.
Access to the calibration switch can be secured
with a lead wire or pressure sensitive security
seal. The remote and primary indicators have no
metrological features that require the use of a
security seal.

Model 7620U Bench Scale User’s Manual
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Internal Resolution
Dynamic Response
Communications
1 part in 2,000,000
The time interval of weight applied to scale until
stable weight is displayed.
0 - 1000d, 350 msec
1000d+, 500 msec
Maximum mean average
Factory default settings: 9600 baud, 7 data bits,
even parity, 1 stop bit.
Standard 9-pin pass through RS-232 interface
cable included. Not a null modem.
RS-232 bidirectional configurable 1200 to 19.2 K
baud. Transmits weight and scale status when-
ever ASCII “W” <CR> is sent by a remote device.

Model 7620U Bench Scale User’s Manual 7
Initial Setup
Unpacking the Scale
Installing the Scale
1. Check container for any obvious evidence of
damage.
2. Remove contents of the shipping container.
3. Inspect the scale for shipping damage.
Immediately report any damage to the
shipper.
1. Mount the scale on a stable, level surface
free from air currents and vibration. Be sure
the scale platter does not touch any adjacent
surfaces.
2. If you want to install the scale surface flush
with a countertop, use these dimensions to
guide construction:
7620U Platform Minimum Cutout
Dimensions Dimensions
356 mm Wide 375 mm Wide
318 mm Deep 337 mm Deep
104 mm Minimum Height
3. Loosen the plastic collars on the leveling
feet. Level the scale by using the level bubble
under the scale platter as a guide. Be sure all
four feet are in firm contact with the counter,
then tighten all collars.
4. Make sure all power cords, remote display
cables, etc. are not touching the live weighing
surface.
5. Plug the unit into an appropriate voltage
outlet, properly grounded.

Model 7620U Bench Scale User’s Manual
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If the scale is outside
the ±10% zero
window, center dashes
are displayed.“_ _ _ _”
Reapply power to
reset the initial zero
setting.
Operation
Power Up
Test Sequence
If RAM or ROM error is
reported, you must
press the F1 key to
acknowledge the
condition.
Performing a Normal
Weighment
When the unit is first powered on it will perform a
test sequence. During this sequence the display
will show the following:
• The model number and software revision
level
• A numeric counting test to all segments of
the display
• A test of Random Access Memory (RAM)
• A test of Read Only Memory (ROM)
If everything is OK, the display will show zero
weight and the scale is ready for use.
1. With the scale powered on, make sure the
scale platter is empty and the display is at
zero. If it is not, press the ZERO key…
“0.000” is displayed.
2. Place an item to be weighed on the scale
platter…
The scale will display the gross weight.
3. Remove the item from the scale platter.
Model 7620 U
Resident Display

Model 7620U Bench Scale User’s Manual 9
Operational Controls
Remote Display
Accessing the
Menu Mode
Accessing the
Gravity Setting Mode
ZERO Key – The ZERO key will zero the scale
if weight is stable, functions as the NO or
SCROLL key in the Menu mode, and as the
INCREASE key in the Gravity mode.
F1 Key – The F1 key can be used to recall the
scale configuration information during the
initial power-up test sequence. This key also
functions as YES or ACCEPT in the Menu
mode, and as the DECREASE key in the
Gravity mode.
All NCI 7620 bench scales can have an
optional remote display (shown above with no
keyboard function). If a remote display with
keyboard is used, then Switch 3 (shown in
Figure 1) determines which display keyboard
is functional.
Switch 3 Settings
Closed= internal display keys operational
Open = external display keys operational
The 7620 family powers up in normal weighing
mode ready for weighing operations. You can
access the Menu mode by setting Switch 1
shown in Figure 1 to the OPEN or Menu mode
position.
Access the GRAVITY setting mode by setting
Switch 2 shown in Figure 1 to the OPEN or
GRAVITY mode position.

Model 7620U Bench Scale User’s Manual
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Figure 1
7620 U Switch Location
Menu Mode
Gravity Mode
There are three modes available to you with
Switch 1 in the MENU Mode or OPEN position.
They are as follows:
1. DIAG Mode – To test areas of the scale’s
function
2. CONFIG Mode – To configure your scale for
your application
3. CAL Mode – To calibrate the scale
With Switch 2 in the GRAVITY Mode or OPEN
position, you may increase the “Local” gravity
value by pressing the ZERO key or decrease the
value by pressing the F1 key.
The structure for these menus is shown in
Figure 2. Specific information about each mode
and step-by-step instructions for accessing them
follow.

Model 7620U Bench Scale User’s Manual 11
Figure 2
7620U Menu Structure
(1) To change the ‘Local’ gravity setting, press the ZERO key to increase the value, or
press the F1 key to decrease the value. When done, set Switch 2 back to the CLOSED
position.
Table 1
Capacity Alternate Calibration
Weights
5-30 5, 15, 30 kg
6-30 5, 15, 30 kg
6-35 5, 25, 35 kg
5-50 5, 25, 50 kg

Model 7620U Bench Scale User’s Manual
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Diagnostics Mode
Diagnostic (DIAG) Mode The Diagnostic (DIAG) mode menu lets you test
specific areas of the scale’s function.
These areas are:
Display (DISPLAY) – Shows the version and
revision of the software, followed by a display
segment test.
RAM (RA) – Performs a nondestructive test of
RAM in the processor. Displays “PASS” or
“FAIL.”
ROM (RO) – Performs a checksum of all loca-
tions in ROM in the processor. Displays “PASS”
or “FAIL.”
Input/Output (I-O) – Data is output by the scale
and through the use of a loopback connector the
data is immediately read back into the receive
channel and verified against what was sent.
“PASS” or “FAIL” is displayed. Requires a
jumper (short) between transmit and receive data
lines.
Division, test w/AZT (DIV-A) – Weight data is
normalized to 1,000,000 counts of displayed
resolution. AZT is enabled (Auto Zero Tracking).
Division, test w/o / AZT (DIV-N) – Weight data
is normalized to 1,000,000 counts of displayed
resolution. AZT is disabled.
Raw Counts (RA CNTS) – Non-normalized QDT
cell data (no zero tracking).

Model 7620U Bench Scale User’s Manual 13
Step-by-Step
Instructions for
DIAG Mode
Press the ZERO key to
scroll through lists of
selections
Press the F1 key
to make a selection
Follow these steps to access the tests in the
DIAG menu (Refer to Figure 2).
1. From normal weighing mode, move Switch 1
to the Menu Mode or OPEN position.
“DIAG” is displayed.
2. Press the F1 key…
“DISPLAY” is displayed.
3. Press the F1 key to perform the display test
described earlier…
Display test is performed and shows
“DISPLAY” after the test is completed.
4. Press the ZERO key…
“RA” is displayed. This stands for the
RAM test.
5. Press the F1 key to perform the RAM test…
“PASS” or “FAIL” is displayed briefly. If
the test fails, the unit may have a RAM
memory failure. Try the test a second
time and if “FAIL” is displayed, contact
your Weigh-Tronix service provider.
6. Press the ZERO key…
“RO” is displayed. This stands for the
ROM test.
7. Press the F1 key to perform the ROM test…
“PASS” or “FAIL” is displayed briefly. If
the test fails, the unit may have a pro-
gram memory failure. Try the test second
time, and if “FAIL” is displayed, contact
your Weigh-Tronix service provider

Model 7620U Bench Scale User’s Manual
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DIAG will flash every
10 seconds during the
high resolution test to
remind you that you
are doing a test and
not seeing normal
weight readings.
8. Press the ZERO key…
“I-O” is displayed. This stands for the
Input/Output test.
9. With a loopback connector in place, press
the F1 key to perform the I/O test…
“PASS” or “FAIL” is displayed. If the
test fails, the unit may have a serial
interface failure. Check your connections
and/or contact your Weigh-Tronix service
provider
10. Press the ZERO key…
“DIV-A” is displayed. This stands for the
high resolution test with AZT enabled.
11. Press the F1 key to perform this test…
The display shows the weight on the
scale at a resolution of 1,000,000 counts.
12. Press the F1 key to stop the test.
13. Press the ZERO key…
“DIV-N” is displayed. This stands for the
high resolution test without AZT enabled.
14. Press the F1 key to perform this test…
The display shows the weight on the
scale at a resolution of 1,000,000 counts.
15. Press the F1 key to stop the test.
16. Press the ZERO key…
“RA CNTS” is displayed. This stands for
raw counts.
17. Press the F1 key to perform this test…
The display shows non normalized cell
data.

Model 7620U Bench Scale User’s Manual 15
Configuration Mode
Configuration
(CONFIG) Mode
18. Press the F1 key to stop the test.
19. When you are finished with the test, press
the ZERO key, until “DONE” is displayed.
Press the F1 key, or place Switch 1 back to
normal mode to return to normal weighing
mode.
The Configuration (CONFIG) mode menu lets
you configure your scale to your specific applica-
tion needs. The items you can configure are as
follows:
Filter (FILTER) – Choose from “FLTR ON” OR
“FLTR OFF.” Default is “FLTR ON.” In a stable,
vibration free location, the “FLTR OFF” setting
could be used if quicker display response is
desired.
Baud (BAUD) – Choose one of the following
baud rates: “1200, 2400, 4800, 9600, and
19200.” Default is “9600.”
Parity (PARITY) – Choose from: “NONE, EVEN,
or ODD.” Default is “EVEN.”
Protocol (Prot) – Choose communication
protocol: “NCI STD” for standard NCI protocol,
“H-100” for 100 times displayed resolution using
the “H” command, “7611” for Canada Post-
ROSS , or “NCI SMA” for Scale Manufacturers’
Association Standard for Scale Serial Communi-
cations. Default is “NCI STD.”

Model 7620U Bench Scale User’s Manual
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Step-by-Step
Instructions for
CONFIG Mode
Follow these steps to access and configure the
items in the CONFIG menu. Refer to Figure 2.
1. From the DIAG display press the ZERO key,
or from normal weighing mode, move Switch
1 to Menu Mode or OPEN position, then
press the ZERO key…
“CONFIG” is displayed.
2. Press the F1 key…
“FILTER” is displayed.
3. Press the F1 key…
The current setting is displayed. Use the
ZERO key to toggle between “FLTR
ON” and “FLTR OFF”
4. Press the F1 key…
Filter selection is stored.
5. Press the ZERO key…
“BAUD” is displayed.
6. Press the F1 key…
The current setting is displayed. Use the
ZERO key to toggle between the five
choices: “1200, 2400, 4800, 9600, or
19200” baud
7. Press the F1 key…
Baud rate selection is stored.
8. Press the ZERO key…
“PARITY” is displayed.
9. Press the F1 key…
The current setting is displayed. Use the
ZERO key to toggle between the three
choices: “EVEN, ODD, NONE.”
Press the ZERO key to
scroll through lists of
selections.
Press the F1 key to
make a selection
Tip: Quickly and easily
view current scale
configuration directly
from the front panel
without opening the
scale or setting
switches as follows:
During the display
segment test on
power-up, press the
F1 key. The display
will prompt “ABORT”
followed by “BAUD.”
Press the ZERO key to
scroll through the
choices, or press the
F1 key to view a
current scale configu-
ration.
When you are done,
press the ZERO key
until “DONE” is
displayed. Press the
F1 key to return to the
normal weighing
mode.

Model 7620U Bench Scale User’s Manual 17
Calibration Mode
10. Press the F1 key.
Parity selection is stored.
11. Press the ZERO key…
“PROT” is displayed.
12. Press the F1 key…
The current setting is displayed. Use the
ZERO key to toggle between the four
choices: “NCI STD, H-100, 7611, NCI
SMA.”
13. Press the F1 key…
Protocol selection is stored.
14. When finished configuring your scale, press
the ZERO key until the display shows
“DONE,” then press the F1 key.
Or, move Switch 1 to CLOSED position for
normal weighing mode.
The Calibration (CAL) Mode menu lets you
calibrate your scale. The items in the Calibration
menu are as follows:
Capacity (5-30, 6-30, 6-35, 5-50)
Select the capacity of your scale.
Follow these steps to calibrate your scale. Refer
to Figure 2.
1. From normal weighing mode, move
Switch1 to the Menu Mode or OPEN posi-
tion…
“DIAG” is displayed. Press the ZERO
key until “CAL” is displayed.
Calibration (CAL) Mode
Warning! Entering into
this mode can erase
the calibration already
saved. You need
approved calibration
weights to use
calibration mode.
Step-by-Step
Instructions for
CAL Mode

Model 7620U Bench Scale User’s Manual
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Division size for a
scale calibrated
as a:
6-30:
0-6 kg x 0.001 kg
6-30 kg x 0.005 kg
5-30:
0-5 kg x 0.001 kg
5 -30 kg x 0.005 kg
6-35:
0-6 kg x 0.001 kg
6-35 kg x 0.01 kg
5-50:
0-5 kg x 0.005 kg
5-50 kg x 0.01 kg
If this procedure is
attempted without any
calibration weights
applied, the scale will
abort the process and
retain the original
calibration data.
Close Switch-1 if you
don’t have correct
calibration weights.
2. Press the F1 key to start calibration…
The current capacity setting is displayed.
Use the ZERO key to scroll through the
choices of capacities: “5-30, 6-30, 6-35,
5-50.”
3. When the correct capacity selection is
displayed,press the F1 key…
The scale prompts LOAD 0.
4. Clear all weight from the scale platter and
press the F1 key…
After a brief wait “LOAD XX” (XX=the
span weight) is displayed. Alternate
calibration points can be chosen using
the ZERO key to toggle between
choices.
5. Place the chosen (alternate) calibration
weight on the scale and allow it to stablize
and then press the F1 key…
After a brief wait “DONE” is displayed.
The scale then prompts “CAL.”
6. Remove the calibration weight and press the
ZERO key…
“DIAG” is displayed.
OR…
7. Return Switch 1 to the closed position…
The scale returns to normal weighing
mode.
The scale is now tested, configured and cali-
brated. It is ready for use in your application.

Model 7620U Bench Scale User’s Manual 19
Gravity Mode
The CAL-GR and
LOC-GR values may
be viewed anytime.
See Review Scale
Setting section.
Warning: Using this
feature in “sealed”
applications may be
subject to approval by
the appropriate
governing agency
at the end-users site.
Gravity value roles
‘over’ at 9.8400 and
rolls ‘under’ at 9.7700.
The Gravity Mode feature provides a means of
adjusting the scale’s internal calibration factors to
compensate for variations in acceleration due to
gravity at different geographic locations. These
differences can cause a given mass to indicate a
slightly different weight at an end-user’s (local)
site than it did at the Calibration (CAL) site.
To make the adjustment, you must know the
value of the gravity constant for the local site.
This value is expressed in meters per second,
per second (i.e., m/s2). It is not necessary to
calibrate the scale, therefore, no calibration
weights are needed to make this adjustment.
The scale maintains two gravity setting values.
The first is the “calibration-site” value known as
CAL-GR. The second is the end-user or “local-
site” value and is known as LOC-Gr. When the
scale was originally calibrated at the factory, the
CAL-GR and LOC-GR values were both set to
9.8040 which is the gravity constant for the
manufacturing site.
To adjust the displayed weight value, you must
enter the local gravity value.
To enter the Gravity Mode, set Switch 2 to the
OPEN position. The display will indicate the
current “local” gravity value. Press the ZERO key
to increment the value or the F1 key to decre-
ment the value. The gravity value will change in
steps of .0001. When the correct value is dis-
played, simply return Switch 2 to the CLOSED
position. The scale will now use this new relation-
ship between calibration and local gravity for its
weight calculations.

Model 7620U Bench Scale User’s Manual
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Press the ZERO key to
move to the next item
in the menu.
Press the F1 key to
select the displayed
item to view.
When the scale is calibrated, the CAL-GR value
is automatically set equal to the LOC-GR setting.
Therefore, it is recommended that you verify the
local gravity setting is accurate before doing a full
calibration.
Pushing the F1 key during the segment test on
power-up, will allow you to view current scale
setup.
When finished viewing the settings, press the
ZERO key until “DONE” is displayed. Then
press the F1 key to return to normal weighing
mode of operation.
Review Scale Settings