Ideas in Measuring ..
TECHNIQUES LIMITED
Page 2
LDU 68 Series Manual
1
INTRODUCTION & SPECIFICATIONS
3
2
COMMUNICATIONS & GETTING STARTED
4
2.1
Serial Interface
4
2.2
Command Language
4
2.3
Setup baud rate / device address
5
2.4
Display mode
5
2.5
Getting Started
5
3
HARDWARE & WIRING
6
3.1
Load Cell Connections
7
3.2
Power Connections
7
3.3
Logic Inputs and Logic Outputs
7
3.4
Communication Connections
7
4
COMMANDS OVERVIEW
10
5
COMMANDS
12
5.1
System diagnostic Commands - ID, IV, IS, SR
13
5.2
Checkweigher Commands - SD, MT, TE, TL, TR, GA, SA
15
5.3
Calibration Commands - CE, CM, DS, DP, CZ, CG, ZT, FD, CS, ZI
18
5.4
Motion detection Commands - NR, NT
21
5.5
Filter setting Commands - FL, FF, UR
22
5.6
Set Zero/Tare and Reset Zero/Tare Commands - SZ, RZ, ST, RT
23
5.7
Output Commands - GG, GN, GT, GS, GF, GW, GA
25
5.8
Auto-transmit Commands - SG, SN, SF, SW, SA
27
5.9
Commands for external I/O control - IN, IO, IM
28
5.10 Setpoint Commands - Sn, Hn, An
30
5.11 Communication setup Commands - AD, CL, BR, DX, OP, TD
32
5.12 Save calibration, setup & setpoint parameters Commands - CS, WP, SS, GI, PI 34
6
CALIBRATION PROCEDURE
35
7
USE IN “APPROVED” APPLICATIONS (LDU 68.1 ONLY)
36
8
SOFTWARE (FIRMWARE) DOWNLOADS
37
8.1
Firmware updates for the LDU XX.X series
37
9
UNIT ADAPTOR CONNECTION DETAIL
38
9.1
UA 77.1 Unit Adaptor with built-in RS422 to RS232 converter
38
9.2
UA73.2 Standard Unit Adaptor
39
10
USB to RS422/485 CONVERTER WIRING (Multi-drop application)
40
Issue 1h
Ideas in Measuring ..
TECHNIQUES LIMITED
Page 3
LDU 68 Series Manual
The LDU 68 amplifier series are precise, mid-speed digital amplifiers for weighing and force
measurements applications which use strain gauge (SG) based sensors. The LDU 68.1 can be used
in both legal for trade and industrial applications. The LDU 68.2 is not Weights & Measures
approved but still offers a lower cost solution for industrial applications. Both devices feature full
multi-drop communication capability and can be programmed using the straight forward ASCII
command set.
The LDU XX.X series and the DAS72.1 amplifier with on-board digital display, use the same
command set. So you can connect up to 32 SG amplifiers of either the LDU X.XX series or the
DAS72.1 types onto a single RS 485 bus.
The LDU 68 series with its high precision 17 bit A to D converter and a mid-speed sample rate of 80
samples per second, is particularly suitable for static measurements and control.
Accuracy Class
EU Type approved
Linearity
Load Cell Excitation
Load Cell Drive Capability
Analogue Input Range
Minimum input per vsi
Resolution
Conversion rate
Digital filter
Calibration
Computer Interface
Weighing functions
Inputs
Outputs
Temperature effects
Temperature range
Enclosure
Dimensions
Power supply
Options
EMC/Approvals
III or IIII (LDU 68.1 ONLY)
R76 10000 Divisions (LDU 68.1 ONLY)
<0.005% Full Scale
5 V DC
Input impedance 80-5000 Ohms (12-14V DC Supply), 6-wire technique
Input Impedance 350-5000 Ohms (14-24V DC Supply), 6-wire technique
±2.48 mV/V (bipolar, for push/pull weighing or tension/compression forces)
50nV per interval non-approved, 1.0µV per interval approved
Internal max ±165,000 counts, external max ± 99,999 counts
Up to 80 measurements per second
0.02Hz - 5Hz second order (i.e.40 dB/decade)
Software calibration and set up
RS485 or RS422 full duplex, 9600 ... 115200 Baud; up to 32 devices on a bus.
Zero, gross, tare, net, filter etc.
2 opto-isolated inputs, 10-30 VDC max. 3 mA
2 open collector outputs, <30 V DC
On zero:<10 ppm/°K (LDU 68.1):<50 ppm/°K (LDU 68.2)
On span:<5 ppm/°K (LDU 68.1):<40 ppm/°K (LDU 68.2)
-10°C to +50°C (compensated); -20°C to +60°C (storage)
Tin plated steel enclosure sealed to IP 40
82 x 31 6 mm, weight approx. 30 g; with adaptor board 91 x 41 x 12 mm
approx. 50 g
12 ... 24 V DC ±10%, <60mA, not galvanically isolated.
Adaptor board UA73.2 (passive) or UA77.1 (RS422 to RS232)
CE 73/23/EEC; 93/98/EEC and 89/336/EEC
All dimensions in mm. Dimensions and specifications are subject to change without notice.
1 INTRODUCTION & SPECIFICATIONS
Technical Specifications of the LDU 68 Series:
Issue 1h
