Kleinwächter EFM 255 User manual

MANUAL
Electrostatic Field Meter EFM 235 / 255
System Prof. Dr.-Ing. Hans Kleinwächter

2 Manual EFM 20
Contents
General information about electrostatics ................................................................................................................ 3
Origin of electrostatic charge ................................................................................................................................... 3
Product description........................................................................................................................................................... 3
Measuring principle ..................................................................................................................................................... 3
Application Areas .......................................................................................................................................................... 3
Specifications .................................................................................................................................................................. 4
Legend .................................................................................................................................................................................... 4
Start Condition .................................................................................................................................................................... 4
Manual .................................................................................................................................................................................... 5
Startup Menu ................................................................................................................................................................... 5
Main Menu ........................................................................................................................................................................ 5
Sub Menu => MODE ...................................................................................................................................................... 6
Sub Menu => ZERO ....................................................................................................................................................... 6
Sub Menu => START ..................................................................................................................................................... 7
Sub Menu => OFF .......................................................................................................................................................... 8
Measure Range .................................................................................................................................................................... 9
Tripod Connection ............................................................................................................................................................. 9
Battery Supervision........................................................................................................................................................... 9
Grounding........................................................................................................................................................................... 0
Electric Field Strength ................................................................................................................................................... 0
Voltage Metering with MK / HMK40 .................................................................................................................... 0
Scope of Delivery .............................................................................................................................................................
Maintenance ......................................................................................................................................................................
NiMH Storage Battery ................................................................................................................................................... 2
Warranty ............................................................................................................................................................................. 2
Warning Notices .............................................................................................................................................................. 2
Calibration.......................................................................................................................................................................... 2

3 General information about electrostatics
General information about electrostatics
Nowadays ESD is a problem at many workstations, because modern microelectronics
2
are
easily destroyed by the sequels of ESD. Other branches of industry like e.g. telecommunications-,
plastics-, and explosive material industry are also heavily affected by ESD.
ESD causes losses of time as well as high financial losses and can endanger the human health.
Charges of over 0000 Volts can have effects on people, clothes, materials, and
equipment. Devices that are sensitive to electrostatics can be damaged by electrostatic
discharges of less than 00 Volts.
Charges of 3000 Volts and more can cause sparks. In endangered areas that can cause
explosions.
Origin of electrostatic charge
Triboelectricity
3
is caused by attrition of different materials. Electrons are transferred from one
material to the other. As electrons are charged negative the material that releases electrons is
charged positive. The material emitting electrons is charged negative. There are different ways
to avoid or to discharge electrostatic charges. But to find an effective and reasonable solution
first the emitted amount and polarity of the charge must be found. Our devices are suitable for
that purpose and for the supervision of desired charge.
Product description
The unit is housed into an EMV aluminum enclosure. The influence electrode is star shaped. In
front of it in a small distance apart a rotating grounded modulation propeller with the same
shape as the electrode is located. The influence electrode is enclosed by a ring electrode system
that is used as a mechanical shield for the propeller wheel and the sensor plate. Measurement
values are displayed on a graphic LC display.
The device has an integrated micro processor with USB 2.0 Interface.
Measuring principle
The electrostatic field meter is a parametric amplifier. The electric field influences a current
proportional to the electrostatic field. The current is amplified and measured with a selective
amplifier. No energy is taken from the field over time means.
No radioactive matters are used!
Application Areas
Detection and Control of electrostatic fields resp. charges, measuring of electric charges, electro-
static charges, very high-resistance voltage sources, very low currents, or high resistances.
electrostatic discharge
2
integrated circuits
3
Greek: tribeia = friction

4 Manual EFM 20
Specifications
Dimension (L x W x H): 170mm x 77mm x 73,5mm
Weight: 550gr
Calibration in a plate capacitor: 400mm x 400mm, Distance 00mm
Calibration acc racy: < 2%
Interface: Mini USB 2.0 Buchse
Power s pply: Power supply 230V 50Hz sek. 9V 300mA
Battery: 4 xNiMH rechargeable Battery AA
Operating time: Min. 4h
Legend
Start Condition
The protective cap on the mod lator system in front
m st be removed before meas ring!
1 Graphic LC-Display 6 Charge Control-LED
2 Zero - Potentiometer 7 Power Interface
3 „ENTER“ Button 8 Modulator System with
cover (protective cap)
4 „On“ „“ Button 9 Connection for MK
5 Mini USB Interface 10 Grounding Jack

5 Manual
Manual
By pressing the «ON» Button (4) on the back of the unit it switches on.
In the display it appears for 3 sec. :
Startup Menu
It shows the Type = EFM 235/EFM 255 and the Version Number V X.X
After that, the unit switches to:
Main Menu
In the dark field it shows the selected Mode.
Press the „“ Button (4) to select the Sub Menu.
Selected Menu is black => ( START )
Press the „ENTER“ button (3) to go to the selected Sub Menu.

6 Manual EFM 20
Sub Menu => MODE
First the upper line is black. By pressing the „“ Button(4) you can change the Mode.
Selection => E-Feld => V-Meter MK1 => HV-Met.MK40 => E-Feld => etc.
Press the „ENTER“ button (3) to choose the selected Mode and the 2nd line becomes black
By pressing the „“ Button(4) you can switch between AUTO and MANUAL .
Press the „ENTER“ button (3) to choose the selection and the 3
rd
line becomes black.
Press the „ENTER“ button (3) again to go back to the Main Menu.
By pressing the „“ Button(4) you come back to the st. line and you can start a new
selection.
Sub Menu => ERO
In the dark field it shows an advice to set the cover (protection cap) onto the modulator system.
Press the „“ Button (4) to select START or BACK.
Press the „ENTER“ button (3) by Start the Zero adjustment starts, by Back you switch back to the
Main Menu.
The buttons are out of function during the Zero procedure.
Do not remove the cover during this procedure! Displayed Range 0-3 is in process.

7 Manual
After successful Zero adjustment it displays
Press the „ENTER“ button (3) to go back to the Main Menu.
By pressing the „“ Button(4) and select Start then pressing „ENTER“ button (3) you can
restart the Zero adjustment.
If no Zero adjustment is possible it appears in the display:
In this case adjust by the Zero Potentiometer on the back the Voltage to V < 0, 0V
After that, press the „ENTER“ button (3) to Start the calibration again.
Sub Menu => START
In the st. line it shows the selected Measure Mode => AUTO and the actual Range => 2kV/m.
In the 2nd line it shows by E-Feld Measurement  E = (act al val e) kV/m
Press the „ENTER“ button (3) to go back to the Main Menu.

8 Manual EFM 20
In case the “MANUAL” Mode is chosen it appears in the display:
In the st. line it shows the selected Measure Mode => MANUAL
and the Selected Range => 2kV/m.
In the 2nd line it shows by E-Feld Measurement  E = (act al val e) kV/m
By pressing the „“ Button(4) you can change the Measure Range.
Press the „ENTER“ button (3) to select BACK and again to go back to the Main Menu.
By selected Measure Mode => Voltmeter MK or HMK40 it appears in the display:
The service is like the E-Field Mode.
Only in the 2nd line it shows the voltage  V = not E = and V not kV/m.
Sub Menu => OFF
Press the „“ Button (4) in Main Menu to select OFF
Then Press the „ENTER“ button (3) to switch off.
After a few seconds the instrument will switch off !

9 Measure Range
Measure Range
By E-Field Measurement you can chose the following Ranges:
Range EFM255 EFM235 Gain Factor
3 200V/m 2kV/m x 100
2 1kV/m 10kV/m x 20
1 4kV/m 40kV/m x 5
0 20kV/m 200kV/m x 1
By Voltage Measurement with the HV – Measuring Heads you get following ranges:
Range MK1 255 MK1 235 MK40 235*
3 2 V 20 V 400 V
2 10 V 100 V 2 kV
1 40 V 400 V 8 kV
0 200 V 2 kV 40 kV
* The Measuring Head HMK 40 is only applicable with the EFM 235..
In Mode „AUTO“ the ranges switches automatically !
Tripod Connection
Battery Supervision
The device has an integrated battery supervision function.
If the battery voltage decreases below 4.8V, in the display appears “Low Battery”.
By decreases below 4.5V it appears in the display “Switch OFF”
To prevent total discharge of the battery the device is automatically powered off. In this case the
battery has to be loaded on the power interface (7) with the shipped charger for about 2- 4h.
To use the Instrument on a table (with MK ) you can change the
handle to a tripod.
To release the hand grip, loosen the attaching finger screw (wheel).
Then screw the tripod into the recessed thread.
Please notice, that the screw thread in the recessed thread is a M6
thread and the thread on the tripod is an imperial thread.
Screw it until finger tight.

0 Manual EFM 20
Grounding
The device must be grounded properly to measure the amount and the polarity of an electro-
static field.
For that purpose, the device must be connected to ground by using the grounding jack ( 0) on
the bottom.
Grounding the device by a grounded person (e.g. over conductive shoes or wrist strap) touching
the handle suffices under most circumstances.
Electric Field Strength
For measuring the electric field strength at first the protective cap must be removed. Afterwards
the electro static field meter must be adjusted with the modulator system parallel to the object
to be measured.
The distance between the EFM 20 and the object to be measured must be kept constant, as the
distance is for the voltage calculation. The measured field strength is displayed in kV/m.
The charge in Volt is obtained by multiplying the displayed value with the distance in meters.
For example: The distance between the object and the device is d=5cm and the measured field
strength E = ,6kV/m, the surface potential U is calculated as follows:
Surface charge = field strength x distance d (m)
U = E x d (in m) => U = 600V/m x 0,05m = 80 V
Please pay attention to use correct units. To avoid these problems, we recommend using SI units.
Voltage Metering with MK1 / HMK40
With the optional voltage gauge head MK /HMK40 voltages up to ±2kV/40kV can be measured
with an internal resistance R
i
> 0
6
Ω. For high voltage measurements the guidelines of the
European standard EN 0 00 need to be considered.
The voltage gauge head must be mounted on the modulator system of the static meter for mea-
surements
The generated linear voltmeters have the following outstanding properties:
Inp t capacitance: approx. 5pF
Inp t resistance: > 0
6
Ω with appropriate gauge head