Flintec LDU 78.1 - Manual (Page 6)

LDU 78.1 Technical Manual, Rev. 12 May 2011 Page 6 of 36
3. Introduction and Specifications
The model LDU 78.1 is a very precise high-speed digital amplifier for weighing and force measurements with
strain gauge (SG) sensors. The LDU 78.1 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 78.1 with its accurate A to D converter and an internal sample rate of up to 2400 measurement
values per second, is particularly suitable for static or dynamic measurements and control purposes.
LDU 78.1 Specifications
Accuracy class III
Test certificate according OIML R76 10 000 intervals and n x 10 000 intervals (n = 2, 3 …)
Linearity < 0.002 % FS
Excitation
5 V DC, for load cells > 350 Ohm ( > 87,5 Ohm at supply voltage
up to max. 14 V DC); 6 wire technique
Analogue input range
±11 mV (bipolar; for weighing applications, force and torque
measurements)
Minimum input sensitivity 0.05 μV/d
Certified accuracy according OIML R 76 0.3 μV/vsi
Resolution
± 260 000 counts (input); ± 100 000 counts (output)
Conversion rate 2400 values/second internal, up to 600 values/second external
Digital filter
FIR Filter 2.5 to 19,7 Hz or IIR Filter 0.25 to 18 Hz;
Each in 8 steps adjustable
Calibration By software via ASCII commands, sehr einfach durchführbar
Communication interface
RS485 oder RS422; Voll-Duplex oder Halb-Duplex;
9600 ... 115200 Baud; busfähig bis zu 32 Einheiten
Standard weighing functions Gross, tare, net, zero, etc.
Digital inputs
2x opto-isolated inputs, 10 ... 30 V DC max. 3 mA,
Status via software
Digital outputs 2x open collector outputs, < 30 V DC, max. 200 mA
Temperature effect on zero Typical < 5 ppm/°K; max. < 7 ppm/°K
Temperature effect on span Typical < 4 ppm/°K; max. < 6 ppm/°K
Temperature range –15 °C to +55 °C (operation); –30 °C to +70 °C (storage)
Enclosure
Tinned steel enclosure, IP20 protection,
special IP65 housing on request
Dimensions and weight
82 x 31 x 6 mm, weighs approx. 30 g;
with adaptor board 99 x 41 x 12 mm, approx. 50 g
Power supply 12 ... 24 V DC ±10 %, < 60 mA, not galvanically isolated
Available accesoires
Adaptor board UA73.2 (RS485 / RS422) or
Adaptor board UA77.1 (inkl. converter RS422/RS232)
EMC OIML R-76:2006 and DIN EN 45 501:1992/AC1993