BECKHOFF DK9222-1209-0007 User Manual
I/O
Application Note DK9222-1209-0007
Measurement technology
Keywords
Energy measurement
Power factor
Energy analysis
EtherCAT Terminal
Bus Terminal
KL3403
EL3403
Consideration of the energy efficiency of a plant by
means of energy measurement
The measurement of energy consumption variables in the connected circuit is possible using the KL3403 Bus
Terminal and the EL3403 EtherCAT Terminal: the terminals directly output the effective values for voltage,
current and active power and total up the energy consumption internally; further parameters can be
calculated on the basis of the values determined.
Approach
Energy costs belong to the operating costs of a plant and are accounted for as overheads in lump sum shares to all cost
centres, since they cannot be attributed to any particular originator. In order to increase profits by reducing energy costs, the
costs must primarily be attributed to a particular consumer. This could similarly be entire plants or buildings or also individual
segments. If the consumption can be attributed, the optimisation of operating conditions is easier to implement and, in case of
doubt, their benefit also proven. By means of a transparent supply network, savings potentials can be specifically implemented
and the success of individual measures can also be observed in the long term. Furthermore, the financial expenditure for the
production of a certain lot size can be adopted into the cost calculation, since the energy throughput per production lot can be
determined as a result.
For application notes see disclaimer on the last page
Beckhoff
New Automation Technology
1
Application Note DK9222-1209-0007
Active power
P
Apparent power
S
Reactive power
Q
Active power factor
cos φ
Reactive power factor
sin φ
Electric work
W
~ Energy consumption
= U * I * cos φ
= U
eff
* I
eff
= P2+Q2
= U * I * sin φ
=
=
= U * I * t
P
S
Q
S
Q
S
P
φ
Measurement technology
As a rule, the following are starting points that need to be addressed in order to reduce energy costs:
– reduction in electricity costs: total active energy obtained, reactive power costs and also costs for peak loads
– stabilisation of manufacturing processes and avoidance of production losses
– identification of ‘energy hogs’
– lowering of maintenance costs
– extension of the service lives of electronic and electrical equipment
– cost centre allocation
Both the EL3403 EtherCAT Terminal and the KL3403 Bus Terminal provide the hardware for the analysis and localisation of
I/O
energy consumption. In addition to the important data from a three-phase supply network, they also record any energy peaks
occurring over a selectable time period and total up the energy consumption internally, so that different modes of operation or
shifted peak usage times can be judged even after just one production cycle. In addition to a general consideration of energy
efficiency, the quantity of energy used for the production of a particular lot size can be determined in order to adapt the price
per unit accordingly or to optimise manufacturing costs.
Function of the KL3403 Bus Terminal
The KL3403 Bus Terminal enables analysis via the fieldbus of the energy consumption of the connected plant or building
segment or, quite specifically, the key energy data of individual consumers. The voltages of the three phases and neutral can be
measured by directly wiring the individual cables to the terminal. In order to measure current, the current of the three phases
L1, L2 and L3 is fed in via simple current transformers. The measured current and voltage values are output as effective values.
From the effective values for voltage (U) and current (I), the KL3403 calculates the effective power (P), the energy consumption
(W) and the power factor (cos φ) for each phase. The apparent power (S) and the phase shift angle (φ) can be derived from
these values.
For application notes see disclaimer on the last page
Fig. 1: Calculation of the important energy consumption variables
Beckhoff
New Automation Technology
2
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