Pennsylvania 7400 User manual

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Pennsylvania Scale Company
Model 7400 Digital Indicator
Operation Manual
Pennsylvania Scale Company
1042 New Holland Avenue
Lancaster PA 17601
For online interactive tech support or more information on Pennsylvania
Scale products, visit our website at www.pascale.com
Revised September 3,2002

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7400 SERIES INDICATOR -OPERATIONS -SECTION 1
CONTENTS
INTRODUCTION -7400 Indicator 2
INSTALLATION and SET-UP 3
CONNECT A PLATFORM 3
ATTACHING NON-PENNSYLVANIA PLATFORMS 4 -5
DIAGNOSTIC FUNCTIONS 4 -5
OPERATIONS
FEATURES 6
EXTERNAL CONNECTORS 6
DISPLAYS AND INDICATORS 6
PUSH-BUTTON FUNCTIONS 7
WEIGHING
WITHOUT TARE 8
WITH TARE 8
BI-DIRECTIONAL SERIAL ASCII INTERFACE 9
COMMUNICATION CAPABILITIES 9
RS-232 ASSIGNMENTS 10
IMPLEMENTED FUNCTIONS 10
TYPICAL CABLE WIRING 10
RS-232 DEFAULT SETTINGS 10
COMMAND FORMATS 11
RS-232 SCALE COMMANDS 12
SAMPLE COMPUTER PROGRAM14
ERROR MESSAGE LIST 16

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INTRODUCTION
This operating manual covers the Operations and
Programming/CalibrationofthePennsylvania Scale Model 7400 Indicators.
The 7400 Series Indicator is designed to be simple and easy to operate. It has many
features that makes it extremely versatile to use such as:
ØStandard RS-232 Interface with a selectable output for communications with a
computer or printer
ØAdjustable response time
ØOptional push-buttons
ØOptional remote displays
ØSingle board electronics for ease of servicing.
In addition, the Model 7400 Indicator can also be calibrated for a lb/oz split display
read out suitable for postal or mailing applications. The indicator can be calibrated with the
keypad or through the RS-232 Interface to match the requirements of the application on hand
as it employs a digital calibration technique that eliminates dip switches and potentiometers.

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INSTALLATION AND SET-UP INSTRUCTIONS
This 7400 has been packaged for shipment to ensure safe, damage-free arrival.
Please use reasonable care when removing the unit from the shipping carton, and retain the
original packaging materials in case reshipment is required.
NOTE: TO PROTECT THE WARRANTY, FILL OUT AND RETURN THE
WARRANTY CARD AND THE SCALE CONDITION REPORT.
The 7400 is designed to be used with a separate load cell based weight platform. This
platform may have a 1, 2, or 3 mv/v sensitivity and a bridge resistance of 87 to 2000 ohms.
On the 7400 Smart Box, 7400M, and 7400MS connection to the platform is made through a
round CPC style connector on the bottom of the box, beside the line cord. All Pennsylvania
Scale non-wash down platforms are shipped with the proper mating connector and need only
be plugged into the 7400. The 7400SS (Stainless Steel) does not have an external connector
but is provided with a water tight Heyco bushing thru-which to feed the platform cable.
TO CONNECT A PLATFORM TO A 7400SS:
Open the 7400SS enclosure by loosening the screw clamps on the top of the box and
opening the indicator lid. The main printed circuit board assembly is mounted in the back of
the box and just below it is a smaller PCB with a terminal block, this is the load cell
connector. Each terminal is labeled as to it's function, follow the wiring table below:
WIRE COLOR FUNCTION TERMINAL
(Pennsylvania Scale platforms) LOCATION
GREEN + SIGNAL # 1
WHITE -SIGNAL # 2
SHIELD SHIELD # 3
------ ------ # 4
BLACK -SENSE # 5
BLUE -EXCITATION # 6
RED + SENSE # 7
BROWN + EXCITATION # 8
A four wire load cell hook up may be used but is not recommended. If a four wire
hook up is necessary, short +EX to +SE and -EX to -SE on the connector.

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ATTACHING NON-PENNSYLVANIA PLATFORMS
If the 7400 Indicator, 7400M and 7400MS is to be attached to a platform of a
manufacture other then a Pennsylvania platform, a mating CPC connector will have to be
ordered. This kit is available through your Pennsylvania Scale Distributor, Order Part
Number 48445. CPC connector wiring assignments are as follows:
CONNECTOR PIN# FUNCTION
1 ............................................... + Signal
2 ............................................... -Signal
3 ............................................... Ground
4 ............................................... Key
5 ............................................... -Sense
6 ............................................... -Excitation
7 ............................................... + Sense
8 ............................................... + Excitation
NOTE:If a four wire hook up is used short connector pin 5 to 6 and 7 to 8.
After attaching your 7400 to a platform, it may be activated by plugging the line cord
into any grounded 50/60 hertz 120 volt outlet (220 volt if the option was ordered). The 7400
will begin a diagnostic countdown. During this countdown the display (on 7400M,7400MS,
7400SS or a 7400 Smart Box with a remote display option) will first show the version
number of the software, followed by 9.9.9.9.9.9. through 0.0.0.0.0.0. Each number
representing a self-diagnostic test to verify the operation of important unit functions. If the
scale should fail any of these tests the display will freeze on that number. (A diagnostic
failure may be bypassed by pressing the ZERO button.)
The serial interface on all models will also transmit the test numbers. The following
table lists each test and its corresponding display.
DISPLAY DIAGNOSTIC FUNCTION
9.9.9.9.9.9. EPROM Checksum, light all LEDS
8.8.8.8.8.8. RAM check
7.7.7.7.7.7. No Test
6.6.6.6.6.6. Check switches not shorted

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DIAGNOSTICS(cont’d.)
DISPLAY DIAGNOSTIC FUNCTION
5.5.5.5.5.5. No Test
4.4.4.4.4.4. Check load cell excitation voltage
3.3.3.3.3.3. Analog Verify (checks output
from analog to digital)
------A to D converter calibration
2.2.2.2.2.2. Load CFG EEPROM, test virgin,
checksum, initialize on error
1.1.1.1.1.1. Load CAL EEPROM, test virgin,
checksum, initialize on error
0.0.0.0.0.0. Test RS-232 Connections
------------ Initializing system (may take
several seconds)
After the countdown is completed, the scale performs an initial zeroing of the system.
No weight should be on the platform at this time.
NOTE: Allow at least 20 minutes for initial warm-up and load cell stabilization.
If the indicator was matched to it's platform at the factory or by your distributor, it is
now ready for operation. If not, please refer to the "Programming and Calibration -Section
2" of this manual for instructions on matching and calibrating the system.

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OPERATING THE 7400 INDICATOR
OPERATIONAL FEATURES
Overload -If the weight exceeds 105% of full capacity, the scale will read out "OLOLOL",
meaning overload.
Underload -If the weight is below -3% of full capacity, the scale will read out "ULULUL",
meaning system underload.
Automatic Zero-Tracking (AZT) -Maintains the system zero to within +/-1/4 of the
display resolution (The resolution being the smallest
increment the scale is programmed to read).
AZT increases the overall accuracy of the system
by removing errors at zero caused by accumulation of
debris on the base/container or minor drifts in the
electronics or load cell.
EXTERNAL CONNECTORS
D-Subminiature Connector (9-pin) -Used with RS-232 Interface.
Remote Display Connector -Used to connect the remote display option to the scale.
DISPLAYS AND INDICATORS
(Available on the 7400M, 7400MS and 7400SS with or without a remote display option or the 7400 Smart Box
with a remote display option.)
Weight Display -Indicates weight when the meter is weighing.
Zero Indicator -Illuminates when the weight is within +/-1/4 of the display resolution of
system zero.
Tare Indicator -Illuminates when a non-zero tare exists.

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OPERATIONAL FUNCTIONS (cont’d.)
PUSH-BUTTON FUNCTIONS
(Available on the 7400M, 7400MS, 7400SS standard and on the 7400 Smart Box with a remote display with
buttons option.)
ZERO ON/OFF Push-button -Sets meter to zero. It also functions as a CONTINUE
switch during the self-diagnostic check (i.e., If the meter
stops at a diagnostic check number, the switch may
be pressed to resume the countdown). If held in for 5
seconds, the unit turns off. Press again to turn on.
TARE Push-button -Enters the weight sitting on the scale as a tare weight. Pressing
Tare Push-button with no weight on scale clears tare weight to zero.
Holding this push-button for four seconds will cause the
current software version to be displayed.
PRINT Push-button -Transmits formatted print to any device connected to the RS-232
port. Holding this push-button for four seconds will access the
RS-232 configuration mode.

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WEIGHING
The following instructions are for the 7400M, 7400MS and 7400SS with or without a
remote display option or a 7400 Smart Box with a remote display option WITH
push-buttons. (The 7400 Smart Box without a remote display with push buttons requires RS-
232 communications to operate. Refer to the RS-232 command section for operating these
scales.)
WEIGHING WITHOUT TARE
Establish a base zero by pressing ZERO and then TARE without anything on the
scale platform to clear any existing weights.
Place the item(s) to be weighed on the platform and read the weight on the
display.
NOTE: If very light items (less then 1/4 of the display resolution) are placed on
the platform individually, the weight may be zeroed off by the AZT
feature. Add light items to the platform simultaneously.
WEIGHING WITH TARE
Establish the tare weight by placing the container or object to be tared-off on the
platform and press TARE. The scale will display the net weight.
When a tare value is stored in the system, the TARE annunciator will be illuminated.
Place the objects to be weighed in the container and read the net weight on the
display. To clear a tare value, remove all weight from the scale, press TARE.

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BI-DIRECTIONAL SERIAL ASCII INTERFACE
INTRODUCTION
The 7400 Serial ASCII Interface is an RS-232C, TTL-compatible, asynchronous
serial interface capable of bidirectional transmission of scale data.
This interface features programmable baud rates, word lengths, stop bits, parity,
address number, and a formatted print.
COMMUNICATION CAPABILITIES
The interface provides three basic types of communication with the Model 7400:
1. Transmission of a predetermined (at set-up time) array of information for formatted
printing. This may be initiated by pressing the PRINT push-button onthe front panel
or remote display with push buttons or by sending "SRP"<CR> ("Send Requested
Print")command to the unit. The scale is shipped from the factory set-up to send the
Gross weight when the PRINT button is pressed.
2. Transmission and alteration of specific data upon request from an external device.
3. Alteration of the unit's operating mode upon request from an external device.
4. Alteration of scale Calibration and RS-232 communications parameters and print
formatting information.(Refer to the "Programming and Calibration -Section 2" of
this manual for more information.)

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RS-232 PIN ASSIGNMENTS AND IMPLEMENTED FUNCTIONS
Connection to the Serial Port is made via a DB-9 female connector found on the
bottom of the indicator.
PIN EIA CODE FUNCTION DIRECTION
2 BB Transmit Data Output
3 BA Receive Data Input
5 AB Signal Ground -
6 CC Data-Set Ready (DSR) Output
7 CB Clear to Send (CTS) Input
8 CA Request to Send (RTS) Output
NOTE: All remaining pins are currently unused and unconnected. For simple
terminal usage where the data rate does not exceed either machine's
capacity to process it, only pins 2, 3, and 5 need to be connected.
TYPICAL CABLE WIRING
To connect to a IBM-AT or compatible use a cable with one male and one female
DB-9 connector with all nine pins connected straight through.
RS-232 DEFAULT SETTINGS
The unit leaves the factory with the following default communication settings :
BAUD 300
WORD LENGTH 7 bits
STOP BITS 1
PARITY ODD
These settings may be changed using the local or remote display keyboard, or RS-232
Interface commands. If the RS-232 Interface is used, initial communication with the users
computer or terminal must be established using the above settings. To return the RS-232
settings to the above default values:
1. Unplug the unit power cord or otherwise remove power.
2. Depress the internal Calibrate button.
3. Plug in (or energize) the unit and continue to hold the
calibrate button for 5 seconds.
For information on how to reconfigure the RS-232 parameters, refer to the
"Programming and Calibration -Section 2" of this manual.

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COMMAND FORMATS
The Model 7400 can be controlled from an external device (such as a computer or
terminal) by various commands, each three letters long, which represent related English
phrases or words. For example, to tell the scale to zero, type ZRO followed by a carriage
return.
When the scale receives command strings, they are first placed in a 125-character
buffer. If many commands are sent to the scale at high baud rates, it is possible to
completely fill this buffer and data will be lost. Be sure to send commands to the scale at a
rate which does not exceed 125 characters every 500 ms.
The basic command formats are:
1. [<add>]<cmd><cr>
2. <cmd> [<flt>]<cr>
Where <cmd> is a three-letter command, <add> is a scale address number
(0-255), <cr> represents a carriage return, and <flt> is a mixed number, the brackets [ ]
are used to indicate an optional part of the command.
The following are some examples of command formats:
Command format 1:
SRP<cr> Send a formatted print
Command format 2:
ITW 13.43<cr> Instructs scale to set tare weight
to 13.43 in the current unit
Command format 3:
5 SGW<cr> Instructs the scale with address #5 to
send the Gross weight.

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MODEL 7400 RS-232 SCALE COMMANDS
General Commands
ATW Acquire Tare Weight
CHK Initiate self-diagnostics CHecK
LCK LoCK out keypad
PON Power ON
POF Power OFf
RES RESet, clears tare weight
UCK UnloCK keypad
ZRO ZeRO scale
Commands Which Enter Information into the Unit
ITW [ FLOATING POINT NUMBER ] Input Tare Weight
Commands Which Request Information
SAI Send All Information
SAO Send Abbreviated Output (same as SRP)
SCI Send Configuration Information
SDT Send DaTe (with time and date option only)
SGW Send Gross Weight
SMI Send Metrological Information
SNW Send Net Weight
SPC Send Print Codes
SRP Send Requested Print
STM Send TiMe (with time and date option only)
STW Send Tare Weight
SVN Send Software Version Number
Calibrate and Configure Commands
CAL CALibrate -Same as pressing SW4 button.
CFC ConFigure Communication -To set baud rate etc.
CFP ConFigure Print codes -To enter print codes.
CLE CaLibration End -To save calibration data.
CLP CaLibrate Primary -To set-up primary calibra-
tion data.
CLU CaLibration Unstable -To set-up print
stable/unstable.
CLW CaLibration Weight -To calibrate with weights.
See NOTES on following page.

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MODEL 7400 RS-232 SCALE COMMANDS(cont’d.)
NOTES: All commands and parameters must be separated by spaces. The entire
command string must be terminated with a carriage return.
All calibrate and configure commands are further explained in the
"Calibration and Programming -Section 2 of this manual.

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SAMPLE COMPUTER PROGRAM
The 7600 Series RS-232 Interface may be tested by connecting it to a terminal with
an RS-232 port, or a computer with an RS-232 and a terminal program. If a terminal program
is not available the following program is provided for an IBM PC or compatible using
BASICA, MBASIC or QuickBASIC.
10 ' Terminal Program written for BASIC Programming Language
20 ' provided by Pennsylvania Scale Company
30 '
40 DEFINT A-Z
50 FALSE = 0: TRUE = NOT (FALSE)
60 KEY OFF: CLS : LOCATE 25, 1
70 PRINT SPACE$(20); "Press Alt-X to Exit Terminal Program"
80 LOCATE 1, 1
90 OPEN "Com1:300,o,7,1" FOR RANDOM AS #1 'Handshaking Enabled
100 OPEN "test.dta" FOR OUTPUT AS #2
110 WHILE NOT (QUIT)
120 KEYBOARDINPUT$ = INKEY$
130 IF KEYBOARDINPUT$ = CHR$(0) + CHR$(45) THEN QUIT = TRUE
140 IF KEYBOARDINPUT$ <> " " THEN PRINT #1, KEYBOARDINPUT$;
150 IF LOC(1) > 0 THEN
160 SCALEINPUT$ = INPUT$ (LOC(1), #1)
170 PRINT SCALEINPUT$; 'Writes data from scale to screen
180 LPRINT SCALEINPUT$; 'Writes data from scale to printer
190 PRINT #2, SCALEINPUT$; 'Writes data from scale to file
200 END IF
210 WEND
220 END
See NOTES on the following page.

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SAMPLE COMPUTER PROGRAM(cont’d.)
NOTES:
Omit line 180 if data is not to be sent to the printer.
Omit lines 100 and 190 if data is not to be written to a file.
In line 100, the word "OUTPUT" opens the file "test.dta", deleting any data that
was in the file before this program was started. If you want to preserve the
contents on the file "test.dta" from one session to another, replace the word
OUTPUT with APPEND on line 100.
Line 90 opens the serial communications port, using 300 baud, Odd parity, 7 data
bits and 1 stop bit. These represent the default settings for the scale, other entries
may be used if the scale settings have been changed. Valid entries for baud rate
are 300, 600, 2400, 4800, 9600, or 19200. Valid entries for parity are N (none), E
(even), or O (odd). Valid entries for data bits are 7 or 8. Valid entries for stop bits
are 1 or 2. Com2 may be used if the scale is attached to serial communications
port #2.
To eliminate the need for attaching the handshaking lines in the cable between the
scale and the computer, change line 90 to read:
90 OPEN "Com1:300,o,7,1,RS,DS0" FOR RANDOM AS #1 'HandshakingDisabled

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ERROR MESSAGE LIST
During Diagnostics:
Err1.CA Scale Calibration
Err2.00 to Err2.63 EEPROM Write Failure
Err2.rS Serial Interface Setup
Err3.Hd Deadload too High
Err3.nS No Sense Line Connected
Err3.-d Negative Deadload
Err4.Sh Load Cell Excitation Shorted
Err6.-1 to Err6.-4 Switch SW1-SW4 Shorted
Err7.nr Defective NOV RAM
Err8.00 to Err8.FF RAM Test Error
Err9.CS Eprom Checksum Error
All Other Times:
Message on Display Explanation Message From ASCII Port
Err2.00 to Err2.FF EEPROM read error "Err2.? EEPROM"
Err 10 Count too large none
Err 11 Keyboard Entry Error none
Err 13 Negative number less then -99,999 (will not fit on display)
Err 30 Illegal Zero none
Err 31 Illegal Tare none
Err 40 Load Cell error none
Err 80 RS -232 Input Error none
Err 81 RS -232 Input Error none
Err 82 RS -232 Overflow none
Err Cnf Config load error on startup "Err 85 Reset to 300 baud"
Err xx* Undefined (Consult Factory) none
ULULUL Load Cell Underload "Err 41"
OLOLOL Load Cell Overload "Err 42"
CalErr RS -232 Cal Error "Calibration Command
Error"
none Bad Print Code "Err 83 Print Code"
none No End Code "Err 84 No Code 99"
* Where "xx" equals any number or character not shown on the above list.

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1
Pennsylvania Scale Company
Model 7400 Digital Indicator
Calibration Manual
Pennsylvania Scale Company
1042 New Holland Avenue
Lancaster PA 17601
For online interactive tech support or more information on Pennsylvania
Scale products, visit our website at www.pascale.com
Revised September 3,2002