LMG500

Precision

Extremely high measuring accuracy

of 0.015 % of reading + 0.01 % of range at 45-65 Hz

Continuity

Complete data collection

In the wake of stricter monitoring of consumption and efficiency of electrical appliances, new standards and procedures (eg SPECpower_ssj2008, IEC 62301, EN50564) will continuously be created to enable an objective comparison of the different manufacturers. Whether it is workstations, servers or appliances, is irrelevant to the principle: The long-term evaluation of the power consumption has always to take all relevant operating conditions into account. The differences between minimum load - e.g., Idle mode, - and full load can thereby be of considerable magnitude, which requires a very sophisticated means of measurement (see also Application Note No. 102, "Measurement of standby power and energy efficiency."). The measurements must be carried out over several hours and may not show any gaps. By selecting a sufficiently large measurement range, range changes and the inevitably resulting data losses can be avoided.
The fundamental precision of the LMG500 also ensures an accurate measurement at the lower limit of a range. 3 MSample/s per channel allow for absolutely gapless sampling with the evaluation of all sampling values.

Harmonics

Monitoring Harmonics with LMG-CONTROL

The spectral analysis of currents and voltages from DC to 1 MHz is supported by the ZES ZIMMER application software LMG-CONTROL. The results can also be exported as tables, e. g. into MS Excel for further processing. Harmonic analysis with LMG-CONTROL ranges up to 1 MHz. The fundamental can be user-defined from 0.07 Hz to 1 MHz. The on-board power supplies of modern large scale aircraft use power distribution systems with frequencies of up to 800 Hz. Basic standards like EUROCAE ED-14D and ABD0100.1.8 have been created to define limit values. Fundamental frequencies from 360 Hz to 800 Hz must be assessed by their harmonics in ranges up to 150 kHz.

Harmonic analysis by ZES ZIMMER software LMG-CONTROL

Ease-of-Use

Easy device settings and intuitive results display

Global settings, shown here is the star-to-delta conversion

Independent setup of synchronization filter and measurement path filter

Selection of input, scaling and measurement range

Different display modes for result in numerical and graphical formats

• A status bar is permanently displayed in all menus
• Measurement display for one or four power  channels, alternatively with six or 20 values, 40 values and more with scroll bars
• Global settings
• Two independent filter sets for the synchronization and the measurement path
• Choice of manual or automatic setting of the measurement ranges

Status bar for overviewing the running measurement

Measurement display with six values

Measurement display with 20 values

Graphical display for wave form	Line plot (trend display)
Vector diagram	Parallel display of harmonics as bar graphs

Scripting

Scripting for automated calculation

Scripting gives users the opportunity to calculate within the power analyzer own additional values and shows them in a customized menu. The script can either be edited in the device, with or without an attached PS/2 keyboard, or
more conveniently written on a PC and downloaded with the aid of LMG-CONTROL.

A good example is the measurement of the characteristics of magnetic cores. The power measured with the exciting current I and the induced voltage U at the sensor winding (core magnetization voltage) directly yields the core losses depending on frequency of up to 10 MHz without the copper losses. With the rectified value of the sensor voltage U – a measure for the voltage-time area and therefore the induced flux – the exciting current I and the geometric core data, the characteristic curves P (Bpk) and Bpk (Hpk) can be generated. With the high-performance script editor the respective curve points are calculated measuring cycle by measuring cycle.
Please also refer to application note No. 108 „Programmer’s Guide“ and No. 109 „Measurement of magnetic characteristics of transformer cores and coil materials“.

Circuitry

Script editor

Custom menu with numerical results

Synchronization

Clustered measurement channels – each with independent synchronization

Up to eight power measurement channels, each of them sampling absolutely synchronously with 3 MSamples/s, are possible with
• a coupled second device or
• the compact 8-channel meter LMG500-8.

The current and the voltage paths of the power measurement channels are all isolated against each other and against earth. The channels are arranged in up to 4 groups (see table): channels 1 to 4 (device 1) into groups A and B and channels 5 to 8 (device 2) into groups C and D. The synchronization source internal, external or “line” and the setup are for each group independently configurable. The settings of groups A and B for certain wirings are independent to the settings of groups C and D. By the 4 groups 4 independent harmonic analyses can be performed.

Event Trigger

Option Event triggering (order no. L50-O5)

Set trigger conditions are evaluated during the normal measuring mode. When a trigger condition is met the scope display will be “frozen“ (shown as “Finish“ in the status bar). The normal measuring proceeds without any interruption and continues to evaluate all sample values. For the sample values u, i, p from different measuring channels, up to four trigger conditions (T1, T2, T3, T4) can be defined and logically linked. A trigger condition can be that a value is larger or smaller than a limit, or inside/outside of a window, for an event duration of 330 ns up to 10 s. The fast sampling captures all peaks and dips. For pre- and postevent analysis up to 2 million samples around the event can be transmitted via the data interface and processed with external software.

Condition menu for event triggering

Star-Delta

Conversion from phase to phase in the phase voltages and determination of the active power

For a 3-phase 3-wire system only the phase voltages U12, U23, U31 and the phase currents I1, I2, I3 are amenable to measurement. With the help of star-delta conversionline, voltages can be determined in the inaccessible phase voltages, converted into the associated active powers. In analogy, the phase currents can be converted into the "chained" currents. From the values ​​thus calculated, all other variables, e.g. harmonics, are derived. Distortions and asymmetries of power and consumers are considered correctly. The use of an external artificial neutral point is thus superfluous, but such can be connected, if required, at any time, in case the associated disadvantages (e.g. increased power dissipation) are accepted.

Interfaces

Powerful interfaces

Excellent connectivity with USB, Ethernet, RS232 and IEEE488.2

Warranty

All ZES ZIMMER power meters of the LMG series, the current sensors of PCT series and the voltage sensors of the HST series are carefully tested, adjusted and calibrated prior to shipment and are subject to strict quality controls.
ZES ZIMMER guarantees for a period of 24 months from first delivery that these products are free from defects in material or workmanship.

ZES Warranty Terms