DS Europe 500QD Series, Инструкция по эксплуатации

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8) ELECTRICAL CONNECTION OF AMPLIFIED LOAD CELLS
8.1 FOREWORD
8.1.1. Series 500 QD; 560QDT; LD; LT; AP 7000 (from 10 up to 100tons FS), PT500,
EG, MD5000 and MP can be made with built-in amplifier electronics.
Series AP 7000 is usually made with built-in analog amplifier electronics (models
from 250Kg up to 5ton FS are miniaturized and do not have enough room inside for
housing the amplifier electronics).
Load cells AP7000, MD5000 and HC2000 have a 1mV/V typical sensitivity (without
amplifier electronics) instead of the usual 2mV/V typical value: these series are
normally under loaded, compared to their mechanical margins, in order to allow a
higher safety against ruptures.
8.1.2 8.1.2. In weighing system with several cells and a summing unit, use cells not
amplified with a summing signal unit mod. Pitagora. The mod. Pitagora can sum
up to eight load cell signals, at the same time, by singularly calibrating each of them
in order to allow a high accuracy.
The amplified cells are not suggested as they are, usually, at different temperature
conditions and the thermal drift of each amplifier and of each stabilizer, even if low,
may add together in the summing unit.
8.1.3 To satisfy the CE directives the amplified load cells have not the calibration lead.
8.2 CHOICE OF THE INTERNAL AMPLIFIER:
Two categories of amplifiers are available of which are listed the advantages and the dis
advantages.
:
The external power supply generator is to have a low ripple electrical noise (linear
generators typically have lower noise than switching types).
Series AP7000 load cells can have inside an analog amplifying electronics only for 10 to
100 tons full scale, but those from 250Kg up to 5tons have only 1mV/V typical sensitivity
because they do not have inside enough room left for any electronics.
8.2.1. Voltage amplifiers:
- A 5 = supply voltage: from 10,5 V to 28 Vdc; Signal output = ± 5 Vdc FS
- A 1 = supply voltage: from 18 V to 28 Vcc; Signal output = ±10 Vdc FS
The Model -A5 is preferable to the Model -A1, as the heat to be dissipated inside the
cell is lower.
EG and 560QDT can have only built-in analog amplifier electronics with positive
outputs 0 to +5 or 10V and not negative.