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Hardware
Docume
Flintec G
Bemann
74909 M
GERMAN
www.flin
bH
bruch 9
ckesheim
ec.com
ion 69.1
Version 6
t No. G1
1.v.2.32 o
.101.5.v.
1 Rev12
higher
.2x
B
Table of Contents:
1. Safety Instructions .................................................................................................................................... 4
2. Declaration of Conformity ........................................................................................................................ 5
3. Introduction and Specifications ............................................................................................................... 6
4. Communications and Getting started ..................................................................................................... 7
4.1. Serial Interface ......................................................................................................................................... 7
4.2. Command Language ................................................................................................................................ 7
4.3. Baud Rate / Device Address .................................................................................................................... 8
4.4. Getting Started ......................................................................................................................................... 8
5. Hardware and Wiring ................................................................................................................................. 9
5.1. Wiring ....................................................................................................................................................... 9
5.2. With Unit Adapter UA 77.1 (RS232) ........................................................................................................ 9
5.3. With Unit Adapter UA 73.2 (RS422 / RS485 Full-/Half-Duplex) .............................................................. 9
5.4. 8-channel Adaptor Board UA 103.1 ....................................................................................................... 10
5.5. Terminal Configuration ........................................................................................................................... 10
5.6. Load Cell Connection ............................................................................................................................. 10
6. Calibration and Calibration Sequence ................................................................................................... 11
7. Commands – Overview ........................................................................................................................... 12
8. Commands Description .......................................................................................................................... 13
8.1. System Diagnosis Commands – ID, IV, IS, SR ..................................................................................... 13
8.1.1. ID Get Device Identity ................................................................................................................................... 13
8.1.2. IV Get Firmware Version ............................................................................................................................... 13
8.1.3. IS Get Device Status ..................................................................................................................................... 13
8.1.4. SR Reset LDU XX.X Firmware ...................................................................................................................... 13
8.1.5. RS Read Serial Number ................................................................................................................................ 13
8.2. Calibration Commands – CE, CM n, CI, MR, DS, DP, CZ, CG, ZT, ZR, ZI, FD, LC, LN n, CS ............ 14
8.2.1. CE Read TAC* Counter / Open Calibration Sequence ................................................................................. 14
8.2.2. CM n Set Maximum Output Value .................................................................................................................. 14
8.2.3. CI Set Minimum Output Value ....................................................................................................................... 14
8.2.4. MR Set Multi-range / Multi-interval ................................................................................................................. 15
8.2.5. DS Set Display Step Size .............................................................................................................................. 15
8.2.6. DP Set Decimal Point Position ...................................................................................................................... 15
8.2.7. CZ Set Calibration Zero Point ....................................................................................................................... 15
8.2.8. CG Set Calibration Gain (Span) ..................................................................................................................... 16
8.2.9. ZT Enable / Disable Zero Tracking ................................................................................................................ 16
8.2.10. ZR Set Zero Range ....................................................................................................................................... 16
8.2.11. ZI Initial Zero Range ...................................................................................................................................... 16
8.2.12. FD Reset to Factory Default Settings ............................................................................................................ 16
8.2.13. LC Clear Linearisation ................................................................................................................................... 17
8.2.14. LN n Linearisation .......................................................................................................................................... 17
8.2.15. CS Save the Calibration Data ....................................................................................................................... 17
8.3. Motion Detection Commands – NR, NT ................................................................................................. 18
8.3.1. NR Set No-motion Range ............................................................................................................................... 18
8.3.2. NT Set No-motion Time Period ..................................................................................................................... 18
8.4. Filter Setting Commands – FL, UR ........................................................................................................ 19
8.4.1. FL Filter Settings ........................................................................................................................................... 19
8.4.2. UR Averaging and Update Rate ..................................................................................................................... 19
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 2 of 28
8.5.
Taring and Zeroing Commands – SZ, RZ, ST, RT ................................................................................ 20
8.5.1. SZ Set Zero ................................................................................................................................................... 20
8.5.2. RZ Reset Zero Point...................................................................................................................................... 20
8.5.3. ST Set Tare ................................................................................................................................................... 20
8.5.4. RT Reset Tare ............................................................................................................................................... 20
8.6. Output Commands – GG, GN, GT, GS, GW ......................................................................................... 21
8.6.1. GG Get Gross Value ...................................................................................................................................... 21
8.6.2. GN Get Net Value .......................................................................................................................................... 21
8.6.3. GT Get Tare Value ........................................................................................................................................ 21
8.6.4. GS Get ADC Sample Value ........................................................................................................................... 21
8.6.5. GW Get Data String “Net, Gross and Status“ ................................................................................................. 21
8.7. Synchronized Output Commands – HW, GH ......................................................................................... 22
8.7.1. HW Hold Weight ............................................................................................................................................. 22
8.7.2. GH Get Hold Weight....................................................................................................................................... 22
8.8. Auto–transmit Commands – SG, SN, SW ............................................................................................. 23
8.8.1. SG Send Gross Value continuously ............................................................................................................... 23
8.8.2. SN Send Net Value continuously .................................................................................................................. 23
8.8.3. SW Send Data String “Net, Gross and Status“ continuously .......................................................................... 23
8.9. Communication Setup Commands – AD, BR, CL, DX, OP ................................................................... 24
8.9.1. AD Device Address ........................................................................................................................................ 24
8.9.2. BR Baud Rate ................................................................................................................................................ 24
8.9.3. CL Close Device Address n .......................................................................................................................... 24
8.9.4. DX Half-duplex or Full-duplex ....................................................................................................................... 24
8.9.5. OP Open Device ............................................................................................................................................ 24
8.10. Save Calibration and Setup Data Commands – CS, WP ................................................................... 25
8.10.1. WP Einstell-Parameter sichern ...................................................................................................................... 25
9. Use in “Approved” Applications ............................................................................................................ 26
10. Updates – Firmware Download .............................................................................................................. 27
RIGHTS AND LIABILITIES
All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any
means, mechanical, photocopying, recording, or otherwise, without the prior written permission of Flintec
GmbH
No patent liability is assumed with respect to the use of the information contained herein. While every
precaution has been taken in the preparation of this book, FLINTEC assumes no responsibility for errors or
omissions. Neither is any liability assumed for damages resulting from the use of the information contained
herein.
The information herein is believed to be both accurate and reliable. FLINTEC, however, would be obliged to be
informed if any errors occur. FLINTEC cannot accept any liability for direct or indirect damages resulting from
the use of this manual.
FLINTEC reserves the right to revise this manual and alter its content without notification at any time.
Neither FLINTEC nor its affiliates shall be liable to the purchaser of this product or third parties for damages,
losses, costs, or expenses incurred by purchaser or third parties as a result of: accident, misuse, or abuse of
this product or unauthorized modifications, repairs, or alterations to this product, or failure to strictly comply with
FLINTEC operating and maintenance instructions.
FLINTEC shall not be liable against any damages or problems arising from the use of any options or any
consumable products other than those designated as Original FLINTEC Products.
NOTICE: The contents of this manual are subject to change without notice.
Copyright © 2010-2011 by Flintec GmbH, 74909 Meckesheim, Bemannsbruch 9, Germany
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 3 of 28
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LDU 69
.1 Technische
s Handbuch,
ev. 12 Jan
ary 2011
Page 4 o
28
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LDU 69
.1 Technische
s Handbuch,
ev. 12 Jan
ary 2011
Page 5 o
28
3. Introduction and Specifications
The model LDU 69.1 is a very precise digital amplifier for weighing and force measurements with strain gauge
(SG) sensors. The LDU 69.1 can be used in legal for trade as well as for industrial applications. The device
features full multi-drop communications capability and can be programmed via a straightforward ASCII
command set.
The LDU XX.X series and the amplifier DAS 72.1 with on-board digital display, use the same command set.You
can connect up to 32 SG amplifiers of either the LDU XX.X series or DAS 72.1 type onto a single RS 485 bus.
The LDU 69.1 with its very precision A to D converter and an internal sample rate of up to 172 measurement
values per second, is particularly suitable for static or dynamic measurements and control purposes. In multichannel applications, e.g. test stands (reference and test sample), the measurements have to be synchronized.
For this purpose there is a 8 channel adaptor board UA103 which is suitable for the synchrone operation of up
to 8 LDU 69.1 amplifiers.
LDU 69.1 Specifications
Accuracy class III
Test certificate according OIML R76 10 000 intervals, n x 10 000 intervals (n = 2 or 3)
Linearity < 0.001 % FS
Excitation 5 V AC (appr. 86 Hz), load cells > 250 Ohm; 6 wire technique
Analogue input range
Minimum input sensitivity 0.02 μV / d
Certified accuracy according OIML R76 0.1 μV / e (legal for trade)
Resolution > ± 1 000 000 counts (input); ± 1 000 000 counts (output)
Conversion rate 172 values/second internal, up to 172 values/second external
Digital filter
Calibration By software via ASCII commands, sehr einfach durchführbar
Communication interface
Standard weighing functions Gross, tare, net, zero, etc.
Temperature effect on zero Typical 1 ppm/°K; max. < 2 ppm/°K
Temperature effect on span Typical 1 ppm/°K; max. < 2 ppm/°K
Temperature range –15 °C to +50 °C (operation); –20 °C to +60 °C (storage)
Enclosure
Dimensions and weight
Power supply 12 ... 24 V DC ±10 %, < 60 mA, not galvanically isolated
Available accesoires
EMC OIML R-76:2006 and DIN EN 45 501:1992/AC1993
±11 mV (bipolar; for weighing applications, force and torque
measurements)
IIR filter 0.2 to 3 Hz; in 6 steps adjustable (0,2; 0,5; 1; 1,5; 2; 3)
Bessel, Gauss or Butterworth characteristics
RS485 oder RS422; Voll-Duplex oder Halb-Duplex;
9600 ... 115200 Baud; busfähig bis zu 32 Einheiten
Tinned steel enclosure, IP40 protection,
special IP65 housing on request
82 x 31 x 6 mm, weighs approx. 30 g;
with adaptor board 99 x 41 x 12 mm, approx. 50 g
Adaptor board UA73.2 (RS485 / RS422) or
Adaptor board UA77.1 (inkl. converter RS422/RS232)
Adaptor board UA103.1 (RS485, for 8 pcs. LDU)
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 6 of 28
4. Communications and Getting started
4.1. Serial Interface
Communicating with the LDU 69.1 digitizer is carried out via the RS422/RS485 port.
The data format is the familiar 8/N/1 structure (8 data bits, no parity, 1 stop bit).
Available baud rates via the RS422/RS485 port are as follows: 9 600, 19 200, 38 400, 57 600 or 115 200 baud.
RS422:
Connection using a 4 wire technique
Point-to-Point connection, i.e. no bus communication possible
Half duplex setup (DX=0)
RS485:
Connection using 2- or 4-wire techniques
Multi-drop connection possible, up to 32 LDU XX.X
Half or Full Duplex (DX=0 or DX=1) possible
(RS232):
The optional adapter board UA 77.1 is available which has an RS485/RS232 converter built in.
4.2. Command Language
The command set of LDU XX.X series is based on a simple ASCII format (2 capital letters). This enables the
user to setup the device, get results or check parameters.
Example: LDU XX.X with the address or channel number 1 is connected via the RS 485 port to a bus system.
You want to get the net weight.
In this manual means: Space “_“ and Enter (CR/LF) ““
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
OP 1
OK
GN
N+123.45
Net weight with algebraic sign / floating point
The command OP_2 opens the communication channel to LDU XX.X device #2. Now device #2 acknowledges
that it is active and responds to any commands on the bus. Communication with device #2 will be closed by
another OP command (for another device on the bus e.g. OP_5) or by the command CL_2.
Each OP_X command implies a CL command to all other devices on the bus except device #X. This makes the
address structures easier and the system performance improves.
Open device #1
Device # 1 ready
Get net weight
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 7 of 28
4.3. Baud Rate / Device Address
Baud Rate:
For baud rate setup use command BR, see chapter 8.9
Factory default: 9 600 baud
Device Address:
For address setup use command AD, see chapter 8.9
Factory default: Address 0
Setting the device address to 0 will set the continuously active mode, where the device becomes permanently
active, and will listen and respond to any command on the bus, without the need for an OP xxx command.
Note: The LDU XX.X series has sets of special solder pads on the under side of the PCB (see chapter 5.1). If
the solder pads are bridged then the LDU will be in a special configuration mode to set up the baud rate and
device address. This function should be used only when baud rate or address is unknown.
After power up, the LDU XX.X will enter a special baud rate search mode – waiting for a space character (0x20)
to be received. The time duration of this character is measured by the LDU and its baud rate timing will be set
accordingly – i.e. the baud rate of the terminal used will be the baud rate used by the LDU subsequently. The
device address will also be set to ”0“
4.4. Getting Started
You will require:
PC or PLC with either a RS422 or RS485 communication port
If using a PC / PLC with RS232 port, a RS422/485 to RS232 converter will be required (option UA 77.1)
Interconnecting cabling - confirm that all relevant pins are used – see the wiring diagram at the end of
this section
A load cell / scale with test weights or a load cell simulator
A 12-24 VDC power supply capable of delivering approximately 100mA for each LDU and load cell
One or more LDU 69.1
A suitable ASCII communication software *
Refer to the following wiring diagram in chapter 5.
* You can easily communicate between a PC and an LDU using programs such as Procomm, Telemate, Kermit
or HyperTerminal (included in Windows).
Also the DOP software with graphical user interface and oscilloscope function, running under Windows
2000/XP is available as freeware. This software is included on the Flintec product CD-ROM (2008 or later).
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 8 of 28
.
5.
H
W
W
W
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W
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r
u
1
2
2
2
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5.1.
5.2.
iring
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UA 77.
(RS23
)
5.3.
LDU 69
ith Unit
.1 Technische
Adapte
s Handbuch,
UA 73.
ev. 12 Jan
(RS42
ary 2011
/ RS485 Full-/H
lf-Dupl
x)
Page 9 o
28
.
5.4. 8
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1
5.5. T
LDU 6
Pin n
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Remarks:
UA 7
Valid
UA 7
erminal
.1
.
.2 (see cha
for half-dupl
.1 with inte
U
Gnd (S
+Exc
+ Sens
+ Sig
– Sig
– Sen
– Exc
Gnd
NC
NC
+ Rx
- Rx
- Tx
+ Tx
NC
NC
NC
NC
+ PWR
Gnd
Configu
73.2
ield)
ter 5.3) is
ex operatio
rated RS42
ation
UA 77
Gnd (Shield)
+ Exc
+ Sens
+ Sig
– Sig
– Sen
– Exc
Gnd
NC
NC
RxD (RS232
Gnd (RS232
Gnd (RS232
TxD (RS232
NC
NC
NC
NC
+ PWR
Gnd
repared for
: pin no. 10
2/RS232 co
1
Co
) Re
) UA
) UA
) Tra
ull-duplex o
+ 13 = A an
verter (see
mon Groun
+ E
citation for l
+ S
nse for load
+ Si
gnal
– Si
gnal
– S
nse for load
– E
citation for l
Sig
al ground /
Not
connected
Not
connected
eive
3.2: Receiv
7.1: Sende
smit
Not
connected
Not
connected
Not
connected
Not
connected
Po
er supply 12
mon ground
eration
d pin no. 11
chapter 5.2
Functi
ad cell
cell
cell
ad cell
V DC
/ UA 77.1:
/ UA 77.1:
...24 V DC
/ 0 V DC
+ 12 = B
on
ommon gro
ommon gro
nd RS232
nd RS232
5.6. L
The load c
cells. The i
The sense
chapter 5.
Flintec lo
LDU 69
oad Cell
ll wiring sh
nput resista
pins of the i
) have to b
d cell; 4 wir
.1 Technische
Conne
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short circui
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and SW2 (s
Page 10 o
d
e
28
6. Calibration and Calibration Sequence
The calibration of LDU 69.1 is only possible after starting a calibration sequence (compare with chapter 8.2).
Command CE: Calibration enable – returns the current TAC value
Command CM1 / CM2 /CM3: Calibrate maximum display – sets the max. allowable display value
Command CI: Calibrate minimum – sets the minimum allowable display value
Command MR: Multi-range / Multi-interval
Command DS: Display step size – sets the output incremental step size
Command DP: Decimal point – sets the position of the output decimal point
Command CZ: Calibrate zero – sets the system zero point
Command CG: Calibrate gain – sets the system gain
Command LC: Clear linearization data
Command LN: If applicable: define up to 7 calibration points
Command ZT: If applicable: Zero track enable / disable
Command ZR: If applicable: Zero range
Command ZI: If applicable: Initial Zero Range
Command FD : If applicable: Factory default setting (return to)
Command CS : Calibration save (TAC counter automatically incremented by 1)
Preparing the calibration:
Check, if the max value of the display is set sufficiently high (see chapter 8.2: command CM1)
Check, if the no motion conditions are defined reasonable (chapter 8.3: e.g. NR = 1, NT = 1000)
Set the filter frequency to 0.5 Hz (see chapter 8.4: FL = 13)
Example: Setup of zero point, system gain and decimal point
The chosen calibration weight has the value 5000 (increments). That could be 500 g, 5 kg or 5000 kg. We
calibrate with 500 g. The decimal point is set up by command DPx (x = 1, 2 or 3), here 1 figure after the
decimal point. A measured weight of 500 g is displayed as 500.0.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
Adjust zero: The scale has to be empty. No load!
CE 17 OK
CZ OK
Adjust gain: First put the calibration weight on the scale (here 500 g)!
CE 17 OK
CG 5000 OK
CG G+05000
CE 17 OK
DP 1 OK
CE 17 OK
CS OK
Zero point, gain and decimal point position were saved in the EEPROM; the calibration counter (TAC) is
increased automatically by 1.
Request: TAC counter CE17
Calibration sequence active
System zero point saved
Calibration sequence active
Setting span
Request: span 5000 d
Calibration sequence active
Setting: decimal point 0000.0
Calibration sequence active
Save calibration data in EEPROM
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 11 of 28
7. Commands – Overview
Command Short description Parameter value Page
AD
BR
CE
CG
CI
CL
CM n
CS
CZ
DP
DS
DX
FD
FL
GG
GH
GN
GS
GT
GW
HW
ID
IS
IV
LC
LN
MR
NR
NT
OP
RS
RT
RZ
SG
SN
SR
ST
SW
SZ
UR
WP
ZR
ZI
ZT
Communication: Device Address 0...255
Communication: Baud Rate 9600…115200 baud
Calibration: Open Calibration Sequence; Read TAC Counter 0...65535
Calibration: Set Calibration Gain (span) at load > zero 0...999999
Calibration: Minimum Output Value –999999...0 d
Communication: Close Device None
Calibration: Set Maximum Output Value (n = 1, 2 or 3) 1...999999 d
Save the calibration data (CMn, CI, DS, DP, CZ, CG, u.a.) to EEPROM
Calibration: Set Calibration Zero Point – scale without load
Calibration: Set Decimal Point Position 0...5
Calibration: Set Display Step Size
Communication: Set Half-duplex (0) or Full-duplex (1) 0 or 1
Factory default settings: Write data to EEPROM (TAC protected) None
Digital filter: Filter Settings 0...17
Output: Get Gross Value
Output: Get Hold Weight
Output: Get Net Value
Output: Get ADC Sample Value
Output: Get Tare Value
Output: Get Data String “Net/Gross/Status“
Output: Hold weight for time-synchronous capturing
Device information: Identify Device
Device information: Identify Device Status
Device information: Identify Firmware Version
Linearisation: Clear data
Linearisation: Define up to 7 calibration points 0...200000 d
Calibration: Define Multi-interval (0) or Multi-range (1) 0 or 1
Motion detection: No-motion Range 0...65535 d
Motion detection: No-motion Time Period 0...65535 ms
Communication: Open Device xxx 0...255
Device information: Read serial number None
Scale function: Reset tare and switch to gross indication
Scale function: Reset zero point
Auto-transmit: Send Gross Value continuously
Auto-transmit: Send Net Value continuously
Reset firmware (warm start)
Scale function: Set Tare and switch to Net Indication
Auto-transmit: Send Data String „Net/Gross/Status“ continuously
Scale function: Set Zero None
Digital filter: Update Rate 0...7 (= 2
Save the Setup Data (FL, NR, NT, AD, BR, DX) to EEPROM None
Calibration: Set Zero range 0...999999
Calibration: Initial Zero Range 0...999999 d 16
Calibration: Disable (0) or enable (1) Zero tracking 0 or 1
None
None
1, 2, 5, 10, 20, 50,
100, 200
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
0
bis 27)
24
24
14
16
14
24
14
17, 25
15
15
15
24
16
19
21
22
21
21
21
21
22
13
13
13
16
17
15
18
18
24
13
20
20
23
23
13
20
23
20
19
25
16
16
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 12 of 28
8. Commands Description
For better clarity, all commands are divided into groups as described on the following pages.
8.1. System Diagnosis Commands – ID, IV, IS, SR
Use these commands you get the LDU XX.X type, firmware version or device status. These commands are
sent without parameters.
8.1.1. ID Get Device Identity
Master (PC / SPS) sends Slave (LDU XX.X) responds
The response to this request gives the actual identity of the active device. This is particularly useful when trying
to identify different device types on a bus.
8.1.2. IV Get Firmware Version
Master (PC / SPS) sends Slave (LDU XX.X) responds
The response to this request gives the firmware version of the active device.
8.1.3. IS Get Device Status
Master (PC / SPS) sends Slave (LDU XX.X) responds
The response to this request comprises of two 3-digit decimal values (067 and 000), which can be decoded
according to the table below:
Leftmost 3-digit value Rightmost 3-digit value
1 Signal stable (no motion) 1 (not used)
2 Zeroing action performed 2 (not used)
3 Tare active 3 (not used)
4 (not used) 4 (not used)
8 (not used) 8 (not used)
16 (not used) 16 (not used)
32 (not used) 32 (not used)
64 (not used) 64 (not used)
The example decodes the result S:005000 as follows:
Note: The bits that are not used are set to zero.
128 (not used) 128 (not used)
Signal stable (no motion) [2
Zeroing action not performed [= 0]
Tare is active [2
ID D:6910
IV V:0232
IS
2
= 4]
0
= 1, LSB]
S:067000 (example)
8.1.4. SR Reset LDU XX.X Firmware
Master (PC / SPS) sends Slave (LDU XX.X) responds
SR OK
This command will respond with ‘OK’ and after maximum 400 ms perform a complete reset of the LDU. It has
the same functionality as power off and on again.
8.1.5. RS Read Serial Number
Issuing the RS command will return the current serial number in the format S:12345678.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
RS S:123456789
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Request: RS = 12345678
Page 13 of 28
8.2. Calibration Commands – CE, CM n, CI, MR, DS, DP, CZ, CG, ZT, ZR,
ZI, FD, LC, LN n, CS
8.2.1. CE Read TAC* Counter / Open Calibration Sequence
With this command you can read the TAC counter (*TAC = Traceable Access Code) or you can open a
calibration sequence.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
This command must be issued PRIOR to any attempt to set the calibration parameters CM n, CI, MR, DS, DP,
CZ, CG, ZT, ZR, FD, LC, LN n or CS. In legal for trade applications the TAC counter can be used to check if
critical parameters have been change without re-verification. After each calibration the TAC counter increases
by 1.
8.2.2. CM n Set Maximum Output Value
This command (CM n with n = 1, 2 or 3) is used to set up the maximum output value (respective the switching
point in multi range applications). Permitted values are from 1 to 999 999.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CM 1 M+030000
CE E+00017 (example)
CE 17 OK
This value will determine the point at which the output will change to “oooooo”, signifying over-range respective
the point at which the output will change the measuring range / interval size.
Application CM 1 = MAX 1 CM 2 = MAX 2 CM 3 = MAX 3
Single range CM 1 = 1...999 999
Dual range or dual interval
( Command MR)
Triple range or triple interval
Teilungen ( Befehl MR)
It is necessary: 1 MAX 1 < MAX 2 < MAX 3 999 999
Note: The range, in which a scale can be set to zero (SZ) or automatic zero tracking (ZT) is active, is +/- 2% of
CM value. Factory default: CM1 = 999 999, CM 2 = 0, CM 3 = 0.
CM 1 50000 OK
CM 2 = 0
(means CM 2 not used)
CM 1 = 1...MAX 1 CM 2 = MAX 1...999 999
CM 1 = 1...MAX 1 CM 2 = MAX 1...MAX 2 CM 3 = MAX 2...999 999
Request: TAC counter CE17
Calibration sequence active
Request: CM 1 = 30 000 d
Request: TAC counter CE17
Calibration sequence active
Setup: CM 1 = 50 000 d
CM 3 = 0
(means CM 3 not used)
8.2.3. CI Set Minimum Output Value
This command is used to set up the minimum output value. Permitted values are from – 999 999 to 0.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CI I–000009
CE E+00017 (example)
CE 17 OK
This value will determine the point at which the output will change to “uuuuuu”, signifying under-range.
CI –10000 OK
Note: In bipolar applications (e.g. force- or torque measurements) this parameter defines the max. output value
for input signals with negative sign. Factory default: CI = –9.
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Request: CI = –9 d
Request: TAC counter CE17
Calibration sequence active
Setup: CI = –10 000 d
Page 14 of 28
8.2.4. MR Set Multi-range / Multi-interval
This command is only relevant, if CM 2 > 0 or CM 3 > 0. Is this the case,then this command defines, if the
application is multi-range or multi-interval. Permitted values are 0 (Multi-interval) or 1 (Multi-range).
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
MR M+00000
CE E+00017 (example)
CE 17 OK
MR 1 OK
Request: MR = 0 (Multi-interval)
Request: TAC counter CE17
Calibration sequence active
Setup: MR = 1 (Multi-range)
Note: Single range applications ignore this parameter.
8.2.5. DS Set Display Step Size
This command allows the output to step up or down by a unit other than 1.
Permitted values are 1, 2, 5, 10, 20, 50, 100 and 200.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
DS S+00002
CE E+00017 (example)
CE 17 OK
DS 50 OK
Notes:
Legal for trade applications allow for up to 10 000 intervals. The allowed step size has to be considered.
In multi-range applications the command DS defines the step size of the lowest measuring range
(command CM 1). The next measuring range (command CM 2 respective CM 3) automatically uses the
corresponding next step size. (e.g. range 1 uses step size 20 range 2 uses step size 50 range 3
uses step size 100). The same applies for multi-interval applications.
Request: Step size 2
Request: TAC counter CE17
Calibration sequence active
Setup: Step size 50
8.2.6. DP Set Decimal Point Position
This command allows the decimal point to be positioned anywhere between leftmost and rightmost digits of the
5-digit output result. Position 0 means no decimal point.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
DP P+00002
CE E+00017 (example)
CE 17 OK
DP 0 OK
Request: Position of decimal point 2
Request: TAC counter CE17
Calibration sequence active
Setup: no decimal point
Factory default: DP = 3
8.2.7. CZ Set Calibration Zero Point
This is the reference point for all weight calculations, and is subject to TAC control.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
CZ 0 OK
Factory default: approx. 0 mV/V input signal
Request: TAC counter CE17
Calibration sequence active
Zero point saved
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 15 of 28
8.2.8. CG Set Calibration Gain (Span)
This is the reference point for calibration under load, and is subject to TAC control.
Permitted values are from 1 to 999 999.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CG G+10000
CE E+00017 (example)
CE 17 OK
CG 15000 OK
Request: Calibration weight = 10 000 d
Request: TAC counter CE17
Calibration sequence active
Setup: Calibration weight = 15 000 d
For calibration an input signal near the display maximum (CM n) will give the best system performance. The
minimum calibration load of at least 20% is recommended. Is the calibration weight smaller than 1% of display
maximum (CM n), the LDU will respond with an error message (“ERR”).
Factory default: 20 000 = 2.000 mV/V input signal
8.2.9. ZT Enable / Disable Zero Tracking
This command enables or disables the zero tracking. ZT = 0 disables the zero tracking and ZT = 1 enables the
zero tracking. Issuing the command without any parameter returns the current ZT value.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
ZT Z:001
CE E+00017 (example)
CE 17 OK
ZT 0 OK
Zero tracking will be performed only on results less than +/-0.5 d at a rate of 0.4 d/sec, where d = display step
size (see DS command). The zero can only be tracked to +/- 2% of maximum (see CM n command).
Factory default: ZT = 0 [Disable]
Request: ZT status
Request: TAC counter CE17
Calibration sequence active
Setup: ZT = Disable
8.2.10. ZR Set Zero Range
This command defines the zero range. Permitted values are from 0 to 999 999.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
ZR R+000100 (example)
CE E+00017 (example)
CE 17 OK
ZR 1000 OK
Request: ZR = 100 d
Request: TAC counter CE17
Calibration sequence active
Setup: ZR = 1 000 d
8.2.11. ZI Initial Zero Range
Defines the initial zero range (0…999999 d). If ZI is non-zero the device will perform an automatic Set-Zero
when the weight stabilizes with the No-motion settings and the weight is within the ZI range. Factory default: 0.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
ZI 100 OK
Request: TAC counter CE17
Calibration sequence active
Setup: Initial Zero range = 100 d
8.2.12. FD Reset to Factory Default Settings
This command puts the LDU back to a known state. The data will be written to the EEPROM and the TAC will
be incremented by 1.
Note: All calibration and setup information will be lost by issuing this command!
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
FD 0 OK
Request: TAC counter CE17
Calibration sequence active
Factory default setting
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 16 of 28
8.2.13. LC Clear Linearisation
This command puts the LDU back to the initial factory calibration using two calibration points, zero at 0.0 mV/V
and 200 000 d at 2.0 mV/V.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
LC OK
Request: TAC counter CE17
Calibration sequence active
Linearize clear
8.2.14. LN n Linearisation
This command makes it possible to inspect and correct more than the two normal nodes set by the CZ and CG
command – up to seven nodes are allowed. Issuing the command with only one parameter (1-7) returns the
node in the format: Ln:XXXXXXX YYYYYYY where XXXXXXX is the input level in mV/V (without decimal point)
and YYYYYYY is the displayed number of increments.
The calibration can be done in the following way: LN1 0 0 defines the zero output at zero mV/V input. LN2
200000 100000 defines 100 000 d at +2mV/V input – at least two nodes must be given.
The following table shows a linearization with 3 nodes.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
LN 1 0 0 OK
CE 17 OK
LN 2 100000 100000 OK
CE 17 OK
LN 3 200000 200000 OK
CE 17 OK
CS OK
LN 3 L3:+200000+200000
Note: Before you re-calibrate with less calibration points use the command LC (as described before).
Factory default: LN = 2 calibration points with 0 mV/V = 0 d and 2 mV/V = 200 000 d.
Hint: By using the load cell’s characteristic data the linearization allows for an electronic calibration (eCal).
Request: TAC counter CE17
Calibration sequence active
Setup: Node 1 = 0 mV/V = 0 d
Calibration sequence active
Setup: Node 2 = 1 mV/V = 100 000 d
Calibration sequence active
Setup: Node 3 = 2 mV/V = 200 000 d
Calibration sequence active
Calibration values saved
Request: Node 3 = 2 mV/V = 200 000 d
8.2.15. CS Save the Calibration Data
This command results in the calibration data being saved to the EEPROM and causes the TAC to be
incremented by 1.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
CS OK
The CS command saves all of the calibration group values, as set by CZ, CG, CM n, DS, DP and ZT. The
command returns ERR and has no updating action unless it is preceded by the CE_XXXXX.
Request: TAC counter CE17
Calibration sequence active
Calibration values saved
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 17 of 28
8.3. Motion Detection Commands – NR, NT
The motion detection facility provides a means of disabling certain functions whenever a condition of instability,
or “motion”, is detected. The “no-motion”, or “stable” condition is achieved whenever the signal is steady for the
period of time set by NT, during which it cannot fluctuate by more than NR increments.The stable condition
activates the relevant bit of responses to “Info Status” (IS).
Following functions are disabled if motion is detected: “Calibrate Zero” (CZ) “Calibrate Gain” (CG) “Set Zero”
(SZ) and “Set Tare” (ST). After such a command the system returns an error (“ERR“), if the signal is not stable.
8.3.1. NR Set No-motion Range
This is the range within which the weighing signal is allowed to fluctuate and still be considered as “stable”.
Permitted values are from 1 to 65535.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
NR R+00010
NR 2 OK
WP OK
Example: For NR = 2 the fluctuations within a maximum of ± 2 d, in the period NT, will be considered “stable”.
Factory default: NR = 1 [= ±1d]
8.3.2. NT Set No-motion Time Period
This is the time period (in milliseconds) over which the weight signal is checked to see if it is “stable” or has “nomotion“. The weight signal has to vary by less than NR divisions over the time period NT to be considered
‘stable’. Permitted values are from 1 to 65 535.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
NT T+01000
NT 500 OK
WP OK
If the value of NT =500 milliseconds, the output must not fluctuate more than NR increments within 500
milliseconds in order to be considered “stable”.
Factory default: NT = 1 000 [ms]
Request: NR = 10 d
Setup: NR = 2 d
Setup saved
Request: NT = 1 000 ms
Setup: NT = 500 ms
Setup saved
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 18 of 28
8.4. Filter Setting Commands – FL, UR
A digital filter can be set which will eliminate most of the unwanted disturbances. The command FL is used to
define the digital filter settings, the command UR is used to define an averaging of up to 172 measurement
values. Please note that these filters are positioned immediately after the A/D Converter and therefore affect all
aspects of the weighing operation.
8.4.1. FL Filter Settings
This command defines the filter cut off frequency and the filter characteristics.
The digital IIR filter operates as 2
The attentuation is 40dB/decade (12 dB/octave).
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
FL F+00003
FL 1 OK
WP OK
The permitted settings are from 0 to 17 (see table below).
Factory default setting: 3 (Butterworth 2 Hz).
Setup of IIR filter
Cut-off frequency 0.2 Hz 0.5 Hz 1 Hz 1.5 Hz 2 Hz 3 Hz
Gauss
Bessel 16 13 10
Butterworth 15 12 9 6 3 0
Filter characteristics:
Gauss: delayed step response (no overswing, minimum group delay)
Bessel: normal step repsonse (no overswing, linear phase)
Butterworth: step response with overshoot (small overswing, linear frequency)
nd
order low pass filter and Gauss-, Bessel- or Butterworth characteristics.
Request: FL = 3
Setup: FL = 1
Setup saved
17 14 11 8 5 2
7
4 1
8.4.2. UR Averaging and Update Rate
For LDU 69.1 following averaging is adjustable:
UR 0 1 2 3 4 5 6 7
Values / second
Check / setup of the averaging:
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
UR U+0000
UR 2 OK
WP OK
Factory default is 0 (no averaging; data output rate = 172 values / second)
172 86 43 21 10 5 2,5 1,3
Request: 172 values / second
Setup: 43 values / second
Setup saved
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 19 of 28
8.5. Taring and Zeroing Commands – SZ, RZ, ST, RT
The following commands allow you to set and reset the zero and tare values. The zero set up during calibration
remains the ‘true zero’ but the new ‘current zero’ can be set up by using the SZ command. If the SZ command
is issued and accepted then all weight values will then be based on the new ‘current zero’. Please remember
that the zero value will be subject to the Zero tracking function if enabled.
If the weight signal is not stable (as defined by the No motion range NR and the No motion time NT) then both
the set zero SZ and set tare ST commands will be disabled.
Also the Set Zero SZ command is not allowed if the new zero value required and the ‘calibration zero’ differ by
more than 2 % of the CM value (maximum allowable value).
See chapter 9 Used in “Approved” applications.
8.5.1. SZ Set Zero
This command sets a new “current zero” which is then the basis of all weight values until further updated by the
zero tracking function, another SZ command or the “reset zero” command RZ.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
SZ OK
The SZ command will fail (LDU responds with ERR) if the new “current zero” is more than 2% (of the CM value)
higher or lower than the “true zero” set during calibration. The SZ command will also fail if the weight signal is
not stable as defined by the No motion range (NR) and the No motion time (NT). If the weight signal is “stable”,
the response to the IS command (Device Status) will show the “signal stable” bit active and the SZ command
will be accepted (OK). If the “signal stable” bit is not active, the SZ command will be rejected and the LDU will
respond with ERR (error).
Set zero performed
8.5.2. RZ Reset Zero Point
This command cancels the SZ command and the zero reading reverts to that set by the CZ command during
calibration.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
RZ OK
Zero point CZ active
The LDU responds to the RZ command with either OK or ERR. If OK is returned then the “zero action
performed” bit in the Device Status (IS) response will be set to “0”.
8.5.3. ST Set Tare
This command will activate the net weighing function by storing the current weight value as a tare.
The weight signal must be “stable” within the limits set by NR (No Motion Range) and NT (No Motion Time)
commands for the “signal stable” bit to be active and set tare command to be accepted.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
ST OK
Tare performed / Net operation
If the weight signal is “stable”, the response to the IS command (Device Status) will show the “signal stable” bit
active and the ST command will be accepted (OK). If the “signal stable” bit is not active, the ST command will
be rejected and the LDU will respond with ERR (error).
8.5.4. RT Reset Tare
This command resets the tare and the weighing signal returns to gross mode.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
RT OK
The LDU responds to the RT command with either OK or ERR. If OK is returned then the “tare active” bit in the
Device Status (IS) response will be set to “0”.
Tare de-activated / Gross operation
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 20 of 28
8.6. Output Commands – GG, GN, GT, GS, GW
The following commands “Get” the gross, net, tare and ADC sample values from the LDU 69.1.
8.6.1. GG Get Gross Value
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
GG G+01.100
8.6.2. GN Get Net Value
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
GN N+01.000
8.6.3. GT Get Tare Value
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
GT T+00.100
8.6.4. GS Get ADC Sample Value
This command gets the actual Analogue to Digital Converter (ADC) value. This can be useful during
development or when calibrating to see how much of the ADC range is being used.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
GS S+125785
For service purposes it may be helpful to note the GS values for the “no-load” or “zero” output and when the
“calibration load” is applied.
Gross value: 1.100 d
Net value: 1.000 d
Tare value: 0,100 d
ADC sample value = 125785 d
8.6.5. GW Get Data String “Net, Gross and Status“
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
Net value: +000100 d (no decimal point)
W+000100+0011005109
GW
(example)
The status bits 1 and 2 are defined as follows:
Status
Value = 1 Value = 2 Value = 4 Value = 8
Status bit 1 Not used Not used Not used Not used
Status bit 2 Signal stable Set zero performed Tare active Not used
The check sum is the reciprocal value of the sum of all ASCII values within the data string without the check
sum itself.
Gross value: +001100 d (no decimal point)
Status bit 1: 5 (not used)
Status bit 2: 1 (Hex)
Check sum: 09 (Hex)
LDU 69.1 Technisches Handbuch, Rev. 12 January 2011
Page 21 of 28
8.7. Synchronized Output Commands – HW, GH
For systems requiring simultaneous sampling of data two commands are available:
8.7.1. HW Hold Weight
Issuing the HW command, which has no parameters, will latch the current net weight in a register for later
readout in all LDU’s in a common network regardless of their individual address.
Note: The LDU’s will not respond to the HW command on the interface lines – it would lead to bus contention
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
HW No response
8.7.2. GH Get Hold Weight
Issuing the GH command, which has no parameters, will return the current hold weight in the format N+000100
from the currently addressed LDU.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
OP 1 OK
GH H+01.100
All other channels (LDU with other address) have to be requested one by one.
Hold weight value in register
Open device #1
Hold weight value: 1,100 d
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8.8. Auto–transmit Commands – SG, SN, SW
The following commands allow the gross weight or net weight values to be continuously sent. Continuous
transmission start as soon as the relevant command has been issued and finishes when any other valid
command is accepted by the LDU 69.1. The data output rate will depend on the baud rate being used e.g. with
a baud rate of 9 600, approximately 100 values per second can be transmitted.
Note: The SG, SN and SW commands will only work if the LDU 69.1 has been set to full duplex [DX=1].
The continuous transmission of either the gross or net values will stop when another valid command is
received.
8.8.1. SG Send Gross Value continuously
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
SG G+01.100
8.8.2. SN Send Net Value continuously
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
SN N+01.000
8.8.3. SW Send Data String “Net, Gross and Status“ continuously
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
Net value: +000100 d (no decimal point)
SW
W+000100+0011005109
(example)
The status bits 1 and 2 are defined as follows:
Status
Value = 1 Value = 2 Value = 4 Value = 8
Status bit 1 Not used Not used Not used Not used
Status bit 2 Signal stable Set zero performed Tare active Not used
The check sum is the reciprocal value of the sum of all ASCII values within the data string without the check
sum itself.
Gross value: +001100 d (no decimal point)
Gross value: 1,100 d
Net value: 1,000 d
Status bit 1: 5 (not used)
Status bit 2: 1 (Hex)
Check sum: 09 (Hex)
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8.9. Communication Setup Commands – AD, BR, CL, DX, OP
8.9.1. AD Device Address
This command can set up the device address in the value range from 0 to 255.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
AD A:000
AD 49 OK
Setting the device address to “0“ will cause the device to be permanently active, listening and responding to
every command on the bus without the need for an OP command. Factory default: AD = 0
Note: After editing the address you first have to save the changes (command WP) and then restart the device.
8.9.2. BR Baud Rate
With this command the following baud rates can be setup: 9 600, 19 200, 38 400, 57 600 and 115 200 Baud.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
BR B 9600
BR 115200 OK
Factory default: 9 600 Baud.
In chapter 4.3 an automatic search and adjusting mode for the baud rate is described.
Note: After editing the baud rate you first have to save the changes (command WP) and then restart the
device.
Request: Address 0
Setup: Address 49
Request: 9 600 Baud
Setup: 115 200 Baud
8.9.3. CL Close Device Address n
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CL 3 OK
CL OK
Close device #3
Close all connected devices
8.9.4. DX Half-duplex or Full-duplex
With this command the serial communication can be set to half-duplex (DX=0) or full-duplex (DX=1).
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
DX X:000
DX 1 OK
Request: DX = 0 (Half-duplex)
Setup: DX = 1 (Full-duplex)
Factory default: DX = 0 (Half-duplex)
Half duplex communication can be used for 2 wire RS485 communication.
Attention: The auto transmit commands SG, SF and SW will only work if full duplex communication (DX=1) is
selected.
8.9.5. OP Open Device
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
OP O:00003
OP 14 OK
This command, if sent without parameters, requests the address or device number of the device active on the
bus. If sent with parameters, this enables the device defined by the parameters.
The requested device acknowledges its readiness and responds to all bus commands until a further OP
command arrives with a different device address or a CL command is received.
All LDUs operate with an improved communication protocoll:
Each OP command implies a CL command for all non-addressed devices. This simplifies the addressing and
increases the performance within the bus system.
Request: Device #3 is open
Setup: Open device #14
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8.10. Save Calibration and Setup Data Commands – CS, WP
The calibration and setup parameters can be divided in 2 groups:
Calibration: CMn, CI, MR, DS, DP, CZ, CG, ZT, ZR, FD, LC and LNn, saved by command CS
Setup: FL, FM, NR, NT, BR, AD, DX and other, saved by command WP
Note: Calibration data can only be saved if the TAC code is known and precedes the CS command. See the
CE and CS commands in chapter 8.2.
The setup data are stored non-volatile in the EEPROM using the WP command.
8.10.1. WP Einstell-Parameter sichern
With this command the settings of the “Filter” (FL, FM) ,the “No-motion” (NR, NT) and the communication (AD,
BR, DX) will saved in the EEPROM.
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
WP OK
WP ERR
Save setup data
Error
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9. Use in “Approved” Applications
The term “approved” applies whenever the weighing application is intended to be used for “legal-for-trade”
weighing – that is, money will change hands according to the weight result. Such applications are bound by the
legal metrology regulations of the relevant governments around the World, but most countries will comply with
either the relevant EN’s (Euro Norms) or the relevant OIML (Organisation Internationale de Metrologie Legale)
recommendations.
The LDU 69.1 has been approved as a component for use in weighing systems according to OIML
recommendation R76, the highest performance level approved being Class III, 10 000 intervals(e) and n x 10
000 intervals (n = 2, 3). The approval Authority was the Danish Electronics, Light & Acoustics (DELTA), and the
approval certificate number was DK0199-R76-03.01 Revision 3, dated 21.12.2010.
This approval will allow the use in approved weighing systems throughout Europe, and in many other countries
of the World. To achieve approval on a particular application, it will be necessary to satisfy the relevant
Governmental Trading Standards Authority that the requirements of the various rules and regulations have
been satisfied. This task is greatly simplified if the key components of the weighing system, namely the load
cells and the weighing indicator or digitizer, are already approved as “components”.
Usually, a discussion with the Weighing Equipment Approvals Officers at the relevant National Weights &
Measures Office will then reveal the extent of any pattern testing that may be necessary to ensure compliance.
Restrictions upon usage when in “Approved” applications
A number of performance restrictions must come into force. These restrictions are the number of display
divisions, which become limited to 10 000 divisions, and the sensitivity per display division, which becomes 0.1
μV per division. Once installed in the application, an “approved” application will require “stamping” by an Officer
of the relevant Governmental Trading Standards Department. This certifies the equipment or system as being
in accordance to the relevant regulations and within calibration limits.
The Traceable Access Code (TAC)
The user software must then provide a guard against improper access of the calibration commands (see the
“Calibration Commands” section). The LDU 69.1 digitizer features the “Traceable Access Code” or TAC method
of controlling the access to the calibration commands group. This means that a code is maintained within the
device, and is incremented whenever any change to any of the calibration commands is saved.
When performing the “stamping” test, the Trading Standards Officer will make a note of the TAC, and advise
the user that any change to this code which occurs prior to the regular re-inspection by the Trading Standards
Office, will result in legal prosecution of the user.
The user software is required as a condition of approval, to make the TAC available to the weight display
indicator or console, on demand.
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10. Updates – Firmware Download
For a software update the LDU xx.x amplifier has to be connected with a Windows PC via the serial interface
(4-wire connection; RS485/RS422 respective RS485/RS232 converter). The solder pads SW4 on the bottom
side of the PCB must be closed before switching on. After the download the solder pads must be opened again.
A download is accomplished with help of our program “PROG78”.
Firmware update for LDU xx.x series:
First all necessary files (LduDownload.exe, progXX.a20, lduXX.a20) have to be stored in same directory. The
firmware for LDU 69.1 is stored in file lduXX.a20.
Close the solder pads SW 4 on the under side of PCB.
LDU XX.X is de-energized
Close solder pads SW4 on the bottom side (see chapter 5.1)
Switch on LDU xx.x
Start program “LduDownload”.
Press button “Load” and choose file ”lduXX.a20”.
Press button “Program”.
At message “Reset LDU before proceeding” switch the LDU XX.X off and on again and press the button
“OK”.
Download proceeds. – The end will be indicated with ”Programming OK “.
Switch off LDU XX.X .
Open solder pads SW 4
Now use a terminal program or DOP software for running a factory reset of the LDU XX.X by using the
command FD
Note: The command FD is TAC protected. You must issue the CE command with relevant TAC code prior to
the FD command else the FD command will fail.
FD Reset to Factory Default Settings
This command puts the LDU back to a known state. The data will be written to the EEPROM and the TAC will
be incremented by 1.
Note: All calibration and setup information will be lost by issuing this command!
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
CE E+00017 (example)
CE 17 OK
FD 0 OK
Request: TAC counter CE17
Calibration sequence active
Factory default setting
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