Transcell Technology PC35 User manual

North American Service Manual
MODEL PC SERIES
Version 2 March 25, 1997
Revision B1.1 April 4, 2000
Prepared by
TRANSCELL TECHNOLOGY, INC.

i
TABLE OF CONTENTS
Page
Chapter 1: Introduction............................................................................................................... 1-1
Chapter 2: Legal for Trade Sealing ............................................................................................ 2-1
2.1 Overview.................................................................................................................. 2-1
2.1.1 Sealing the Scale......................................................................................... 2-1
Chapter 3: General Troubleshooting Flowchart .......................................................................... 3-1
Chapter 4: Illustrated Parts List.................................................................................................. 4-1
4.1 PC-30 & PC-70......................................................................................................... 4-1
4.2 PC-150..................................................................................................................... 4-3
Chapter 5: Assembly / Disassembly........................................................................................... 5-1
5.1 PC-30 & PC-70......................................................................................................... 5-1
5.2 PC-150..................................................................................................................... 5-2
Chapter 6: Internal Wiring Diagram............................................................................................ 6-1
Chapter 7: Theory of Operation.................................................................................................. 7-1
7.1 Theory of Operation Overview.................................................................................. 7-1
7.1.1 Main Board Assembly .................................................................................. 7-1
7.1.2 Display/Key Board Assembly........................................................................ 7-1
Appendix A: Technical Specifications........................................................................................... A-1
Appendix B: Serial Data Formats Information............................................................................... B-1
B.1 Serial Data Formats.................................................................................................. B-1
B.1.1 Serial Data Formats Overview ..................................................................... B-1
B.1.2 Consolidated Controls Demand Format........................................................ B-1
B.1.2.1 Recognized Host Commands......................................................... B-1
B.1.3 Consolidated Controls Continuous Format.................................................... B-2
B.1.4 Toledo 8213 Demand Format....................................................................... B-3
B.1.4.1 Recognized Host Commands......................................................... B-3
B.1.5 NCI 3800 / Triner Demand Format............................................................... B-4
B.1.5.1 Recognized Host Commands......................................................... B-4
B.1.6 Transcell Technology Demand Format......................................................... B-5
B.1.6.1 Recognized Host Commands......................................................... B-5
B.1.7 Transcell Technology Continuous Format..................................................... B-6
B.1.8 Detecto Demand / Continuous Format.......................................................... B-7
B.1.8.1 Recognized Host Commands......................................................... B-7

ii
B.1.9 Fairbanks 70-2453-4 Demand Format.......................................................... B-8
B.1.9.1 Recognized Host Commands......................................................... B-8
Appendix C: Circuit Diagrams....................................................................................................... C-1
LIST OF FIGURES
1-1 PC Series Front Panel........................................................................................................ 1-1
2-1 Location of Calibration Switch............................................................................................ 2-1
2-2 Detail of Calibration Switch ................................................................................................ 2-1
5-1 Opening up the PC-30 and PC-70 Base Unit...................................................................... 5-1
5-2 Opening up the PC-150 Base Unit...................................................................................... 5-3
6-1 PC Series Chassis Wiring Diagram.................................................................................... 6-1
B-1 Consolidated Controls “Demand” Weigh Data Record........................................................ B-1
B-2 Consolidated Controls “Continuous” Weigh Data / Status Record....................................... B-2
B-3 Toledo 8213 “Demand” Weigh Data Record....................................................................... B-3
B-4 Toledo 8213 “Demand” Status Record ............................................................................... B-3
B-5 NCI 3800 / Triner “Demand” Weigh Data Record ............................................................... B-4
B-6 NCI 3800 / Triner “Demand” Status Record........................................................................ B-4
B-7 NCI 3800 / Triner “Demand” Invalid Command Record ...................................................... B-4
B-8 Transcell Technology “Demand” Weigh Data Record......................................................... B-5
B-9 Transcell Technology “Demand” Status Record.................................................................. B-5
B-10 Transcell Technology “Continuous” Weigh Data / Status Record........................................ B-6
B-11 Detecto Weigh Data / Status Record.................................................................................. B-7
B-12 Fairbanks “Demand” Weigh Data / Status Record.............................................................. B-8

1-1
CHAPTER 1: INTRODUCTION
Service and maintenance personnel who desire more technical information than is presented
in the PC Series User’s Guide should use this manual. Any component level troubleshooting
or board replacement should be done by factory authorized personnel only.
The PC Series has three ranges of weight capacities. The PC-30 is a 30 lb (15 kg) scale, the
PC-70 is a 70 lb (30 kg) and the PC-150 is a 150 lb (70 kg) scale.
PC-70
MODEL
ZERO
kg
lb GROSS
NET TARE PRINT
Transcell Technology inc.
CLASS = 1500
max
n
III CAPACITY: 70 x 0.05 lb, 30 x 0,02 kg
Temp. Range: 0 to 40° C
ZERO
TARE
NET
GROSS
STABLE
lb
kg
FIGURE 1-1: PC Series Front Panel

2-1
CHAPTER 2: LEGAL FOR TRADE SEALING
2.1 OVERVIEW
The scale can be prepared for commercial use by sealing access to the calibration switch, to
meet the requirements for a legal-for-trade scale.
2.1.1 SEALING THE SCALE
Once calibration has been successfully completed, then the scale can be sealed as
follows:
1. Referring to Figure 2-1, locate the calibration switch on the back of the scale.
2. Replace the calibration switch cover by securing with the two drilled head
screws.
3. Thread a wire security seal through the openings in both drilled head screws.
This prevents access to the calibration switch. Refer to Figure 2-2 for more
detail.
Calibration Switch
Figure 2-1: Location of Calibration Switch
Drilled Head Screws
Figure 2-2: Detail of Calibration Switch Cover Plate with Drilled Head Screws

3-1
CHAPTER 3: GENERAL TROUBLSHOOTING FLOWCHART
START
Does
Scale Turn On
?
NO
YES
Try The Following In Order Of Appearance:
1. Replace AC Adapter.
2. Check the Display Cable.
3. Troubleshoot or Replace Main PCB.
NO
Try The Following In Order Of Appearance:
3. Replace Load Cell.
4. Replace Main PCB.
2. Check Load Cell Wiring.
Does
Scale Weigh
?YES
NO
Try The Following In Order Of Appearance:
Do the
Keys Work
?YES
1. Check Display Cable.
NO
Try The Following In Order Of Appearance:
1. Check for proper AC Adapter Voltage .Is the
Scale Stable
?YES
2. Check environment.
NO
Try The Following In Order Of Appearance:
1. Check for platform obstruction (i.e. ovld stop).Is the
Scale Linear
?YES
2. Replace load cell if zero offset count too high.
CALL
TRANSCELL
STOP
A
A
1.Try re-calibrating scale.
2. Troubleshoot or Replace Display PCB.
3. Troubleshoot or Replace Main PCB.
3. Troubleshoot or Replace Main PCB.
3. Troubleshoot or Replace Main PCB.

4-1
CHAPTER 4: ILLUSTRATED PARTS LIST
4.1 PC-30 AND PC-70
1
2
4
3
5

4-2
ITEM QTY PART NO. DESCRIPTION
1 1 380190008 Stainless Steel Platform
2 1 211040020 Load Cell – FAD-20 (PC-30)
2 1 211040045 Load Cell – FAD-45 (PC-70)
3 1 380190036 Bottom Spacer - Aluminum
4 1 380190037 Top Spacer - Aluminum
5 4 380190013 Adjustable Foot
– 1 250116237 AC Adapter – 12 VDC, 500 mA
1
ITEM QTY PART NO. DESCRIPTION
1 1 215193811 Main Board Assy
– 1 215366100 Display/Key Board Assy

4-3
4.2 PC-150
5
6
7
1
3

4-4
ITEM QTY PART NO. DESCRIPTION
1 1 380190008 Stainless Steel Platform
3 1 380360001 Top Spacer - Aluminum
5 1 211040100 Load Cell – FAD-100
6 1 380360007 Bottom Spacer - Aluminum
7 4 380190013 Adjustable Foot
– 1 250116237 AC Adapter – 12 VDC, 500 mA

5-1
CHAPTER 5: ASSEMBLY / DISASSEMBLY
5.1 PC-30 and PC-70
Tools Required: 5 mm Allen Wrench
Phillips Head Screwdriver
1. Remove the scale platter (1) and set aside.
2. Using the 5 mm Allen wrench, remove the [2] load cell mounting bolts (2).
3. Lift off the sub-platform assembly (3), and set aside.
4. Remove the [4] mounting screws (5) for the splash plate (4) and set aside.
5. Lift off the splash plate and set aside.
1
3
4
2
5
Figure 5-1: Opening up the PC-30 and PC-70 Base Unit

5-2
5.2 PC-150
Tools Required: 5 mm Allen Wrench
Phillips Head Screwdriver
1. Remove the scale platter (1) and set aside.
2. Using the 5 mm Allen wrench, remove the [2] load cell mounting bolts (2).
3. Lift off the sub-platform assembly and aluminum spacer (3), and set aside.
4. Remove the [4] mounting screws (5) for the splash plate (4) and set aside.
5. Lift off the splash plate and set aside.

5-3
1
2
3
4
5
Figure 5-2: Opening up the PC-150 Base Unit

CHAPTER 6: INTERNAL WIRING DIAGRAM
6-1
RED
GRN
BLK
WHT
3
5
2
Load Cell
DC Power Jack
Female DSUB9
JP2
J1
–
+
Main / ADC Board Assy
GND
SCALE RXD
SCALE TXD
RED
BLK
RED Setup Switch
+
On/Off Switch
1 2 +
LED
RED
GRN
BLK
WHT
1
2
3
4
E+
S+
E–
S–
J8
2
1Ferrite Bead Core
Ferrite Bead Core
J3
1 2 3 4
J2
Female 14-PIN CENTRONICS
TO REMOTE
DISPLAY/ KEY
UNIT (PC-30 &
1 2 3 4 5 6 7 8 9 10
10
9
8
7
6
5
4
3
2
1PC-70 ONLY)
Display/Key Board Assy (PC-150 only)
Figure 6-1: PC Series Chassis Wiring Diagram

7-1
CHAPTER 7: THEORY OF OPERATION
7.1 THEORY OF OPERATION OVERVIEW
Refer to Appendix C for reference designators.
7.1.1 MAIN / ADC BOARD ASSEMBLY
Power to the scale is supplied by a 12 VDC, 500 mA adapter. Regulator U1 supplies
+5 VDC to the digital components. Regulator U8 supplies + 10 VDC to the analog
components including load cell excitation. Switching regulator V5 inverts the + 10
VDC to – 10 VDC to act as the negative supply rail. Regulators V4 and V6 further
regulate to ±8 VDC for the A/D converter IC, U9.
Op-amp U11 forms a high impedance bridge amplifier for the load cell with a fixed
gain of 100. Op-amp U10:B forms a low pass filter to prevent unwanted noise from
entering the circuit. The other half of U10 (U10:A) provides a buffered reference
voltage for op-amp U11. The A/D converter, U1, is a dual slope type converter.
Timing is controlled by the microcontroller.
Microcontroller U2 executes several functions including A/D fetch, digital signal
conditioning, key scan, serial communication, and display output. EEPROM U5
contains calibration data as well as the setup parameters. IC U7 is the EPROM,
which contains program memory. The network around U4 boosts the MCU’s UART
signal to RS-232 level for serial communication with a host device.
7.1.2 DISPLAY/KEY BOARD ASSEMBLY
This circuit contains footprints for 5 keys, display driver (U4) and the LED Display
(U1-U3).

A-1
APPENDIX A: TECHNICAL SPECIFICATIONS
ANALOG SPECIFICATIONS
Full Scale Input Signal 16 mV, including dead load
Internal Resolution Approximately 150,000 counts
Displayed Resolution Up to 3,500 graduations max
Measurement Rate 10 Meas/sec, nominal
System Linearity Within 0.02% of FS
Calibration Method Software Calibration, with long term storage in EEPROM
Excitation Voltage +10 VDC
RFI Protection Signal lines protected by LC Low Pass Filters
Excitation & Power lines protected by EMI Chokes
DIGITAL SPECIFICATIONS
Microcontroller Intel 80C32
Program Memory: 32K x 8, external to µC
EEPROM: 64 x 16, external to µC
SERIAL COMMUNICATIONS
RS-232 Full Duplex, Selectable Baud, Data Bits and Parity
OPERATOR INTERFACE
Display 6-Digit, 0.56” 7-segment LED Display
Keyboard 5-key Tactile Keypad
POWER
AC Adapter 12 VDC, 500mA
ENVIRONMENTAL
Operating Temperature 41°F (0°C) to 95°F (40°C)
Storage Temperature -4°F (-20°C) to 167°F (+75°C)
Operating RH 20% to 95%, non-condensing
Storage RH 20% to 98%
PHYSICAL DIMENSIONS:
13.0 in [330.2 mm]
4.4 in [112 mm]
ON/OFF
SWITCH DC POWER JACK RS-232
PORT REMOTE
DISPLAY
ID TAG
CALIBRATION
SWITCH COVER
13.0 in [330.2 mm]
PC-150 Only
10.2 in [258.0 mm]
PC-30/70
CONNECTOR
(WP-30 & 70 ONLY)

Page B-1
APPENDIX B: SERIAL DATA FORMATS INFORMATION
B.1 SERIAL DATA FORMATS
B.1.1 SERIAL DATA FORMATS OVERVIEW
The COM1 serial port is a full duplex RS-232 port designed for connection to a serial
printer, computer, or remote display. Consult the PC Series Operation Manual for
information on pinouts and cable diagrams.
Through the User Menu, you may choose one of the available SDF’s (Serial Data Formats).
These serial data formats emulate certain makes of scales and make up the Application
Layer. From a Data Link Layer perspective, there are two types: Demand and Continuous.
Some SDF’s can be used with both types but most can be used with only one type.
For Demand types, the scale acts as the client and requires a host (usually a PC). The host
issues a command (typically a single ASCII character) and the scale responds with a weigh
data record, a status record or no record depending on the specific SDF chosen.
NOTE: Use Demand types for interfacing to a serial printer. In this case, data output can be
initiated by pressing the PRINT key on the front panel of the scale. (Host is not required).
For Continuous types, host control is not required – but not restricted either. In this type, the
scale automatically transmits a weigh data / status record out of the serial port at the end of
each display update. Continuous types are used to interface to computers, scoreboards,
and other remote devices requiring constant data updating. Host commands, although not
required, are accepted and acted upon.
B.1.2 CONSOLIDATED CONTROLS DEMAND FORMAT
Figure B-1 shows the weigh data record sent to the host when the scale receives a Print
(“P”) command. The same weigh data record is sent out of the serial port if the PRINT key
is pressed on the scale’s front panel. If the weigh data is invalid, the scale does not
respond. See section below for more information.
<STX> <POL> xxxxx.xx <LB/KG> <GR/NT> <CR> <LF>
Polarity:
<SP> = Positive
"–" = Negative
Weight Data
Units:
lb = pound
kg = kilogram
Gross/Net:
GR = Gross
NT = Net
Start
Transmission Carriage Return
Line
Feed
<SP> <SP>
SpaceSpace
FIGURE B-1. Consolidated Controls “Demand” Weigh Data Record
B.1.2.1 RECOGNIZED HOST COMMANDS
These commands are issued from the host to the scale and are single ASCII
characters.
“P” - This command is sent to the scale to print the indicated display. The scale will
not respond if the scale is in motion, positive overload or negative overload.

Page B-2
“Z” - This command is sent to the scale to zero the scale. The scale will disregard
this command if the scale is in motion, positive overload or negative
overload. The scale will also disregard this command if it is not in gross mode
or within the zero reset range. Even if successful, the host receives no
response from the scale. The host must issue a “P” command to determine if
the command was processed by the scale.
“T” - This command is sent to the scale to tare the scale. The scale will disregard
this command if the scale is in motion, positive overload or negative
overload. The scale will also disregard this command if it displaying a
negative gross value. Even if successful, the host receives no response from
the scale. The host must issue a “P” command to determine if the command
was processed by the scale.
“G” - This command is sent to the scale to revert to gross mode. The scale will
disregard this command if the scale is in motion, positive overload or
negative overload. The scale will also disregard this command if it is not in
net mode. Even if successful, the host receives no response from the scale.
The host must issue a “P” command to determine if the command was
processed by the scale.
“N” - This command is sent to the scale to revert to net. The scale will disregard
this command if the scale is in motion, positive overload or negative
overload. The scale will also disregard this command if it is not in gross mode
or a tare has yet to be established. Even if successful, the host receives no
response from the scale. The host must issue a “P” command to determine if
the command was processed by the scale.
“C” - This command is sent to the scale to toggle among the configured units. Even
if successful, the host receives no response from the scale. The host must
issue a “P” command to determine if the command was processed by the
scale.
B.1.3 CONSOLIDATED CONTROLS CONTINUOUS FORMAT
Figure B-2 shows the weigh data / status record automatically transmitted by the scale at
the end of each display update. The same host commands listed in Section B.1.2.1 are
accepted and acted upon by the scale.
<STX> <POL> xxxxx.xx <L/K> <G/N> <STAT> <CR> <LF>
Polarity:
<SP> = Positive
"–" = Negative
Weight Data
Units:
L = pound
K = kilogram
Gross/Net:
G = Gross
N = Net
Start
Transmission Carriage Return
Line
Feed
Status:
<SP> = Valid
M = Motion
O = Over/under range
FIGURE B-2. Consolidated Controls “Continuous” Weigh Data / Status Record

Page B-3
B.1.4 TOLEDO 8213 DEMAND FORMAT
Figure B-3 shows the weigh data record sent to the host when the scale receives a Print
(“W”) command. The same weigh data record is sent out of the serial port if the PRINT key
is pressed on the scale’s front panel. If the weigh data is invalid, the scale responds with a
status record instead – as shown in Figure B-4. See section below for more information.
NOTE: Since this SDF (Serial Data Format) does not support units of measure. It is
recommended that lb/kg conversion be disabled.
<STX> XXX.XX <CR>
Weight Data
Start
Transmission Carriage Return
FIGURE B-3. Toledo 8213 “Demand” Weigh Data Record
<STX> <?> <SS> <CR>
Start
Transmission Carriage Return
Status Byte: ( "1" = "True")
Invalid Weight
B7 Parity bit
Center of zero
Outside zero capture range
Under zero
B6
Bit Function
Always "1"
Always "1"B5
B4
B3
B2
B1
B0 Out of range Motion
See Table
STATUS BYTE TABLE
FIGURE B-4. Toledo 8213 “Demand” Status Record
B.1.4.1 RECOGNIZED HOST COMMANDS
These commands are issued from the host to the scale and are single ASCII
characters.
“W” - This command is sent to the scale to print the indicated display. The scale
will respond with the status record if the weight is less than zero or the scale
is in motion, positive overload or negative overload. Otherwise, the scale
responds with the weigh data record.
“H” – Same as the “W” command except that the scale outputs an extra character
at the beginning and end of the weigh data record.
“Z” - This command is sent to the scale to zero the scale. The scale will disregard
this command if the scale is in motion, positive overload or negative
overload. The scale will also disregard this command if it is not in gross mode
or within the zero reset range. Whether the command was successful or not,
the scale sends a status record to the host.

Page B-4
“A” - This command is sent to the scale to request an acknowledgement. This
acknowledgement consists of two characters: <STX> and <CR>.
B.1.5 NCI 3800 / TRINER DEMAND FORMAT
Figure B-5 shows the weigh data record sent to the host when the scale receives a Print
(“W”<CR>) command. The same weigh data record is sent out of the serial port if the
PRINT key is pressed on the scale’s front panel. The status record is shown in Figure B-6. If
an invalid host command is received, the scale responds with the invalid command record
shown in Figure B-7. See section below for more information.
<LF> (1) <xx.xxx> (2) <HSB>
Line
Feed
High Status Byte:
Weight Data
Not Used
Not Used
Bit Function
B3
B2
B1
B0 Not at zero Motion
See Table
High Status Byte Table
<LSB>
Low Status Byte:
See Table
<CR> (4)
Carriage
Return
<ETX>
End of
Transmission
Not Used
Bit Function
B3
B2
B1
B0 Over capacity Under capacity
("1" = "True")
Low Status Byte Table
("1" = "True")
Not Used
(1) Insert <SP> for Triner.
(2) Insert <SP> for NCI.
<LB/KG>
(4) Insert <LF> for NCI.
Units (3):
LB = pound
KG = kilogram
(3) Use lower case for NCI.
FIGURE B-5. NCI 3800 / Triner “Demand” Weigh Data Record
<LF> <HSB>
Line
Feed
High Status Byte:
Same as "W"
<LSB>
Low Status Byte:
See as "W"
<CR>
Carriage
Return
<ETX>
End of
Transmission
S<LF> ?<CR>
Line
Feed Carriage Return
FIGURE B-6. NCI 3800 / Triner “Demand” Status
Record FIGURE B-7. NCI 3800 / Triner “Demand” Invalid Command Record
B.1.5.1 RECOGNIZED HOST COMMANDS
These commands are issued from the host to the scale and consist of two ASCII
characters.
“W”<CR> - This command is sent to the scale to print the indicated display. The
host should check the status bytes to determine if the scale is in
motion, positive overload or negative overload.