Mostec VG-BAT Series User manual

Portable Micro-Ohmmeter
VG-BAT-x00
OPERATING MANUAL

Operating manual VG-BAT
Page 2
Warranty
Mostec warrants this product to be free of manufacturing defects for a 2-year period after the
original date of purchase. Within this period, defective products will be repaired free of charge
provided that the defect occurred during normal operation. This warranty does not cover damage to
the product resulting from ordinary usage such as front panel scratches, broken control elements
and corrosion, etc. The customer is responsible for shipping and packing charges for products
returned under warranty to Mostec. Mostec warrants this product beyond the 2-year warranty
period for an additional 2 years in case of long term damages due to improper manufacturing.
Such damages as poorly soldered joints or other assembly problems are also covered by the
warranty. Transportation damages are not covered by the warranty and should be referred to the
respective delivery service.
Technical data
The portable micro-ohmmeters VG-BAT-x00 are used for resistance measurements of high
power switches etc. The strengths of the instruments are the easy handling, battery powered,
rugged design and low weight.
The VG-BAT-x00 enables a real direct current measurement for highest accuracy. The current
rises linear for 1 second than holds the preset current for 3 seconds and falls back within another 1
second.
The advanced build-in LiFePO4 battery offers maximum power with excellent safety and
outstanding life.
The 4.3" LCD graphic display, enables measurements in darkness, coldness and full sunlight.
Measurement data is saved directly to a USB stick and to the internal Memory.
The USB PC-Interface is used to control the device or read out the results automatically by
computer.
Read out the device history or start a measurement with an Android phone or tablet. Send the data
directly to your office.
The VG-BAT-200, with a weight of 5.2kg only, is very handy and easy transportable.
Typical applications are ohmic tests of:
 Circuit breakers
 Disconnecting switches
 High current busbar joints
 Railway parts
 Cable splices
 Welding joints
 Ground connections

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Index Page
1. Safety Regulations ..................................................................................................................................... 4
2. Battery care ................................................................................................................................................ 5
3. Battery disposal.......................................................................................................................................... 5
4. Operating Instructions ................................................................................................................................ 5
5. Control Panel ............................................................................................................................................. 6
6. Power ON ................................................................................................................................................... 7
7. Main Menu ................................................................................................................................................. 7
8. System Menu ............................................................................................................................................. 8
9. System Menu, Description ......................................................................................................................... 9
10. Result Window ......................................................................................................................................... 12
11. Start/Stop Measurement .......................................................................................................................... 12
12. Printer ....................................................................................................................................................... 12
13. Error Messages ........................................................................................................................................ 13
14. Instrument Temperature Monitoring ........................................................................................................ 13
15. Application Example - one side grounded ............................................................................................... 14
16. Application Example - both sides grounded ............................................................................................ 15
17. Verify the measuring current .................................................................................................................... 16
18. Verify the measuring function .................................................................................................................. 16
19. Technical Data ......................................................................................................................................... 17
20. Notes ........................................................................................................................................................ 18

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1. Safety Regulations
Always comply with local safety regulations when using the Micro-Ohmmeter.
Always connect protective earth (ground).
Read and comply with the safety regulations in this manual before using Micro-Ohmmeter.
Never open a breaker as long as the Micro-Ohmmeter is connected.
High voltage/currents can occur at the input/output clamps.
The connection joints of the high current cables may become hot during a test.
Do not subject the instrument to strong impact, mechanical shock or excessive heat.
Do not expose the instrument to water, salt water or other liquids.
This instrument contains a LiFePO4 high energy battery pack and a lithium coin cell.
Do not pierce, damage, disassemble or modify the battery
Testing inductive circuits can be hazardous. The VG-BAT-x00 is a high power instrument,
designed for testing resistive loads. It must not be used to test inductive loads.

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2. Battery care
The battery should be charged at a minimum of 6 month intervals. This is to prevent deep
discharge.
Never attempt to charge the battery below 0°C or above +40°C ambient.
The instrument is specified between -20°C and +50°C. However keep in mind that at very
low temperatures, the battery is stressed and the capacity of measurements is reduced.
Keeping the instrument at room temperatures before doing measurements outside at low
temperatures helps to improve battery life.
The battery is charged by connecting the provided recharger at the DC socket on the back
of the instrument.
If the recharger is connected the LED next to the ON/OFF key illuminates.
The battery charging time is 1.5 hours.
Store the instrument in a cool, dry location to improve battery life.
Storage temperatures below freezing should be avoided. Do not attempt to remove the
batteries from this unit.
3. Battery disposal
The crossed out wheeled bin symbol placed on the batteries is a reminder not to dispose
of them with general waste at the end of their life.
This product contains lithium ion batteries and a coin cell. They are located inside the
instrument. The Lithium ion coin cell can be safely removed by Mostec AG.
4. Operating Instructions
1. Keep the Micro-Ohmmeter switched off while making connections.
2. Ground one side of the test object.
3. Ground the Micro-Ohmmeter.
4. Connect the current cables to the test object.
5. Connect the two sense cables as close as possible to the test object.
6. Switch on the Micro-Ohmmeter.
7. The Micro-Ohmmeter powers up and shows the startup text on the display.
8. Select the desired measuring current with the "ADJUST" keys [+] and [-] or use a
preset current with the keys [F1], [F2] or [F3].
9. Start the measurement with [Start/Stop].
To change the instrument settings, see page 8.

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5. Control Panel
01. LCD 4.3" graphic display
02. Keys to control the menu functions
03. Increment/decrement keys for menus and values
04. Start/Stop keys with status LED
05. Remote control connector
06. Accessories connector
07. USB PC-Interface
08. Data logger / USB stick
09. Current clamp sense input
10. Raw signal shunt voltage terminals
11. Sense terminals
12. DC - current output
13. DC+ current output
14. Power switch with recharging LED
15. Ground terminal
Warning: Opening the instrument case voids the warranty.

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6. Power ON
After power up the display shows the welcome message for 3 seconds. After that, the display
shows the main menu.
7. Main Menu
Iset = The previously set measuring current. The measuring current can be changed by
using the [+] and [-] keys.
Menu = Pressing [Ent], the user enters the system menu.
Reslt = Pressing [Esc], the user enters the window with the measuring results.
10 = Preselect value 1 of the measuring current. By pressing [F1], the measuring current
Iset is changed to 10A. This value can be changed in the system menu.
100 = Preselect value 2 of the measuring current. By pressing [F2], the measuring current
Iset is changed to 100A. This value can be changed in the system menu.
200 = Preselect value 3 of the measuring current. By pressing [F3], the measuring current
Iset is changed to 200A. This value can be changed in the system menu.
= State of charge
= Shows the numbers of remaining measurements for the actual load. On
startup the instrument takes the maximal load for calculation and adjusts
the value with further measurements.

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8. System Menu
Pressing [Ent] in the main menu leads to the system menu. In this menu, the user can navigate
between the items using the [F1] and [F2] key. Pressing [F3] switches between the first and
second page of the system menu. [Ent] selects the actual indicated item. The data of the
selected item can be modified using the keys [+] and [-]. To store the modified data and leave
the selected menu item, press the [Ent] key. [Esc] leaves the system menu without any
changes.

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9. System Menu, Description
First Page
Menu item
Description
Range of values
SM 0
Measure mode
(not available for battery types)
:
The measuring current flows continuously until it's
interrupted by the user. Single = the measuring current
only flows for a fixed given time.
single/continuous
SM 1
Current:
Preset current 1. The adjusted value appears in the main
menu above [F1].
5A to
205A
5A to 305A
5A to 405A
5A to 605A
SM 2
Current:
Preset current 2. The adjusted value appears in the main
menu above [F2].
5A to 205A
5A to 305A
5A to 405A
5A to 605A
SM 3
Current:
Preset current 3. The adjusted value appears in the main
menu above [F3].
5A to 205A
5A to 305A
5A to 405A
5A to 605A
SM 4
Current Clamp:
The instrument calculates the current which can be
bypassed through the grounding connections. This value is
subtracted from the measuring current which flows through
the device under test.
on/off
SM 5
Current Clamp:
Set the sensitivity of the external current clamp in mV/A.
0.10mV/A...20mV/A
SM 6
Temp. Compensation:
When this item is ON, the instrument works with the
temperature coefficient (α, see SM7). It measures the
temperature of the test object with the external
temperature sensor and compensates the temperature
coefficient of the test object.
on/off
SM 7
Temp. Compensation:
Set the value for the temperature coefficient (α) of the test
object that will be measured.
-/+ 9.99 x 10
-
3
1/K
SM 8
Erase measurements:
Erases all saved measurements.
yes/no
SM 9
Buzzer:
Activates key click and audio warning during measurement
and error messages.
on/off
Press [F3] for next page.

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Second Page
Menu item
Description
Range of values
SM
10
Time format:
Switches between 24/12h formats
12h/24h
SM 11
Date format:
Switches between different date formats.
YYMMDD, DDMMYY,
MMDDYY
SM 12
Time:
Adjusts the hour of the internal clock.
0…12 / 0…23
SM 13
Time:
Adjusts the minute of the internal clock.
0…59
SM 14
SM 15
SM 16
Date:
Adjusts year, month, day of internal calendar.
TT
1…31
MM 1…12
JJ 0…99
SM 17
Printer:
Incremental counter for the printout. The printouts are
numbered. The first number is set by item SM17.
0…9999
SM 18
Printer:
The user can switch the printout between simple
and detailed mode.
summary/all values
SM 19
Language:
Select the active language of the display.
English
Deutsch
Español
Swenska
Française
SM20
Display
Ueut:
Displays sense voltage
yes/no
SM21
Auto pol detection:
Disables automatic correction of sense polarity.
yes/no
SM22
Pass/Fail:
Enter submenu for changing limits by the [Ent] key. In
the submenu the limits for the measurement analysis
may be changed.
change limits

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Submenu Measurement Analysis
Enter this submenu by the [Ent] key in the system menu on item SM22. If the measurement
analysis is switched on, then the resistance value will be compared with the selected limits. If the
reading is within the selected limit the display shows “Reading: Pass” otherwise it shows
“Reading:Fail” after a measurement.
[Ent] Save settings and goes back to the system menu
[Esc] Goes back to the system menu without saving
[F1] Shows the previous parameter
[F2] Shows the next parameter
[F3] Changes range of selected preset
The 3 limits can selected at the main menu by the [F1], [F2] and key [F3]. As an example the
selected limit is shown on the main menu view like this: Analysis: 0.0<R<99.0µΩ.

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10. Result Window
The result window can be activated by pressing the key [Esc] in the main menu. It will also be
automatically activated if a measurement has been completed. The Micro-Ohmmeter stores the
last 100 data sets. Unlimited data sets can be achieved by using an external USB stick.
The window shows the time and date of the running test, storage location, ohmic value and test
current. When the external current clamp is activated, the clamp current is shown as well.
[Ent] Prints the data set
[Esc] Goes back to the main menu
[F1] Shows the next result
[F2] Shows the previous result
11. Start/Stop Measurement
The measurement is started by the [Start/Stop] key. This process is announced by the red
blinking LED and, if activated, a pulsating audio alarm (Buzzer).
The measurement can be aborted by the [Start/Stop] or the [ESC] key.
12. Printer
The thermal printer is maintenance free and the paper can be easily changed.
The key under the paper output does the paper feed. The green LED lamp indicates
"printer ready". A blinking green lamp indicates a paper problem.

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13. Error Messages
The Micro-Ohmmeter can detect and display different errors.
Fault
Cause
Remedy
Sense line broken Sense line defective or broken Verify the sense line
connections
Overflow Ohmic value too high for the
selected current
Bad connection and/or too
large resistance
Measuring current value not
reached
1. Instrument overheated
2. Resistance > 999.9mΩ
Cool down the instrument
Bad connection or too large
resistance of the test object.
Too long high current cables.
14. Instrument Temperature Monitoring
The Micro-Ohmmeter has a temperature surveillance controller. At >40°C internal temperature,
the LCD display shows the inside temperature, right, on the first line. At >50°C it derates the
test current. At >70°C the measuring current is set zero.
For more cycles, wait until the internal temperature decreases.
internal temperature

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15. Application Example - one side grounded
Comply to the safety regulations and operation instructions when using the Micro-
Ohmmeter. See page 4 and 5. Never use the instrument without the protective earth
connections!
Important:
The sensing cables must be connected
after the high current cables, as close to
the test object as possible.
If the high power cables are closer to the
test object than the sense lines, the test
data may be incorrect.
Note:
If you are measuring the resistance of a
breaker or disconnecting switch (isolator),
make sure that it is closed and grounded
before making connections and starting the
test.
1. Make certain the mains are de-energized on both sides of the breaker. Ground the breaker
on one side and make sure it is closed.
2. Keep the Micro-Ohmmeter switched off while making connections.
3. Ground the Micro-Ohmmeter.
4. Connect one current cable between one side of the object being tested and the DC+
terminal on the Micro-Ohmmeter. Connect the other current cable between the other side of
the object being tested and the COM terminal on the Micro-Ohmmeter.
5. Connect the two sensing cables on two sides of the test object and as close to the test
object as possible.
6. Switch the Micro-Ohmmeter on.
7. Set the test current using the keys [+] and [-] or use one of the preselected currents using
the [F1] or [F2] or [F3] key.
Note: If you are using the instrument the first time, make sure that the current clamp is
switched off (Setup Menu SM4, see page 9).
8. Press the [START/STOP] key. The measurement is announced by a red blinking LED, and
if activated, a pulsating audio alarm (Buzzer) is on. The result will be shown after a few
seconds. The result is saved, you can make a printout and/or run a new test.
9. You can stop the measurement by pressing [START/STOP] or [ESC] keys.
10. Turn off the Micro-Ohmmeter before doing any disconnection work or moving any cables or
wiring.

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16. Application Example - both sides grounded
Comply to the safety regulations and operation instructions when using the Micro-
Ohmmeter. See page 4 and 5. Never use the instrument without the protective earth
connections!
Important:
The sensing cables must be connected
after the high current cables, as close to
the test object as possible.
If the high power cables are closer to the
test object than the sense lines, the test
data may be incorrect.
Note:
If you are measuring the resistance of a
breaker or disconnecting switch (isolator),
make sure that it is closed and grounded
before making connections and starting
the test.
1. Make certain the mains are de-energized on both sides of the breaker. Ground the circuit
breaker on both sides and make certain it is closed.
2. Keep the Micro-Ohmmeter switched off while making connections.
3. Ground the Micro-Ohmmeter
4. Connect one current cable to one side of the object being tested and the DC+ terminal on
the Micro-Ohmmeter. Connect the other current cable to the other side of the object being
tested and the COM terminal on the Micro-Ohmmeter.
5. Connect the two sensing cables on two sides of the test object and as close to the test
object as possible.
6. Connect the external current clamp to one of the ground bars of the breaker and the clamp
output to the DC current clamp input on the Micro-Ohmmeter.
7. Switch the Micro-Ohmmeter on.
8. Set the test current using the keys [+] and [-] or use one of the preselected currents using
the [F1] or [F2] or [F3] key.
9. In the "Setup Menu", "SM4" (see page 9) switch on the current clamp and adjust the proper
sensitivity of the current clamp you are using.
10. Press the [START/STOP] key.
11. You can stop the measurement by pressing [START/STOP] or [ESC] keys.
12. If the current through the ground bar was too high compared to the current through the
breaker, adjust the test current and start the measurement again. Repeat this step, until the
current through the breaker meets your requirements.
13. Turn off the Micro-Ohmmeter before doing any disconnection work or moving any cables or
wiring.

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17. Verify the measuring current
Comply to the safety regulations and operation instructions when using the Micro-
Ohmmeter. See page 4 and 5.
1. Connect mV-Meter to the shunt output
2. Calculate the measuring current:
Shunt voltage = 100uV/A
Measuring mV
Measuring Current = -------------------------------
Shunt voltage 100uV/A
10mV
For example: ------------- = 100A
100uV/A
18. Verify the measuring function
Comply to the safety regulations and operation instructions when using the Micro-
Ohmmeter. See page 4 and 5.
1. Connect the current cable together
2. Connect the sense cables from the
Shunt-Output to the Sense-Input
terminal
3. Start a 100A, single measurement
4. Result = 99.6uΩ for example
 The value 99.6uΩ must be the same value as in the calilbration certificate (see “shunt output
value”)

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19. Technical Data
Measuring ranges: 0...20.00µΩ, 0...200.0µΩ, 0...2.000mΩ, 0...20.00mΩ, 0...200.0mΩ
0...999.9mΩ
Display: Sunlight readable LCD 4.3"graphic display with a resolution of 480x272 dots
Display resolution: 0.01µΩ ... 0.1mΩ
Accuracy: 0 ...1000µΩ, @ 200A / 25°C = ±0.05% FS
1 ... 25mΩ, @ 200A / 25°C = ±0.2% FS
25 ... 999mΩ, @ 5 - 200A / 25°C = ±0.5% FS
Reproducibility: <0.1%
Measuring current: 5 - 205A (VG-BAT-200), 3 adjustable preset currents
Maximum test voltage: 5.5V
Current ramp: The test current rises following a linear ramp, holds the preselected value and falls with a
linear ramp.
Battery:
Charging:
LiFePO4, 75Wh
CCCV, 1.5hours
Number of Measurements: 200A 27mΩ 58# | 100A 27mΩ 229# | 50A 27mΩ 916#
200A 5mΩ 308# | 100A 5mΩ 1237# | 50A 5mΩ >2000#
200A 1mΩ 1546# | 100A 1mΩ >2000# | 50A 1mΩ >2000#
Measuring interval: No limitation of the number of current cycles
Result data logging: The last 100 data sets are stored internally.
Unlimited data sets for the external USB stick.
Automatic power switch-off: Default 2 minutes
Data logger: Accepts FAT32 formatted USB sticks
Sense input:
Input voltage:
Input impedance:
Independent polarity with banana jacks.
Max. ±5V
>200kΩ
Shunt output:
Shunt voltage:
100µV/A +/-1%, banana jack red = plus, banana jack black = negative
20mV @ 200A for VG-BAT-200
Data interface: USB, various measuring protocols may be set (VG-CS Win, data output, data control)
Pass/Fail: Display signalization, 3 preset limits. Optional alarm contacts
Date/time: The instrument has a battery buffered real time clock
Buzzer: An acoustic click for keyboard operation or an ongoing test
Ambient temperature: -20.0°C ... +50.0°C
Humidity: Max. 95% non-condensing
LVD: RL2014-35-EU, EN 61010-1:2011
EMC: RL2014-30-EU, EN 61326:2008 + A1:2009, EN61000-6-1/2/3/4:2007
Printer: Optional, 24-characters standard thermal paper (58x32mm diameter)
Unit manipulations: Keyboard, external PC or Android phone/tablet
Manipulations: Menu operated, easy to use
Power supply: 100...240V, 1.3A, 50-60Hz
CE-conformity: Fulfilled
Dimensions: L x W x D: 300 x 248 x 195 mm
Weight: 5.2 kg (VG-BAT-200)
Warranty: 2 Years
Software (optional): PC-software to transfer and log stored data sets, Order No: VG-CS WIN
Special accessories: -Customer specific changes
-Current clamp (for example 20mV/A), to measure dual grounded systems
-USB stick

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20. Notes

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Operating manual VG-BAT
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