Notices On Analog Specifications; Full Scale Value (Fsv) - Beckhoff EL3773 Documentation

Commissioning
On the voltage measurement side, a EL3773 is equipped with a protection impedance of 1.8 MΩ. If the
neutral conductor is not connected and only one connection on the side of the voltage measurement is live,
the resulting voltage against earth in a 3-phase system with a phase-to-phase voltage of 400 V
This should also be measured on the side of the current measurement using a multimeter with an internal
resistance of 10 MΩ, which does not represent an insulation fault.
Additional measuring instruments in the current circuit
Please note that the addition of additional measuring instruments (e.g. ammeters) in the current circuit can
lead to a significant increase in the total apparent power.
Furthermore, connection I
Additional measuring instruments therefore have to be potential-free and must be wired accordingly.
6.10

Notices on analog specifications

Beckhoff I/O devices (terminals, boxes, modules) with analog inputs are characterized by a number of
technical characteristic data; refer to the technical data in the respective documents.
Some explanations are given below for the correct interpretation of these characteristic data.
6.10.1

Full scale value (FSV)

An I/O device with an analog input measures over a nominal measuring range that is limited by an upper and
a lower limit (initial value and end value); these can usually be taken from the device designation.
The range between the two limits is called the measuring span and corresponds to the equation (end value -
initial value). Analogous to pointing devices this is the measuring scale (see IEC 61131) or also the dynamic
range.
For analog I/O devices from Beckhoff the rule is that the limit with the largest value is chosen as the full scale
value of the respective product (also called the reference value) and is given a positive sign. This applies to
both symmetrical and asymmetrical measuring spans.
Fig. 143: Full scale value, measuring span
For the above examples this means:
• Measuring range 0..10 V: asymmetric unipolar, full scale value = 10 V, measuring span = 10 V
• Measuring range 4..20 mA: asymmetric unipolar, full scale value = 20 mA, measuring span = 16 mA
• Measuring range -200..1370 °C: asymmetric bipolar, full scale value = 1370 °C, measuring span =
1570 °C
• Measuring range -10..+10 V: symmetric bipolar, full scale value = 10 V, measuring span = 20 V
This applies to analog output terminals/ boxes (and related Beckhoff product groups).
124
of the EL3773 must represent a star point for the three secondary windings.
N
Version: 2.5
is 230 V .
AC AC
EL3773