B&K Precision 310 User Manual

Instruction Manual

Model 310 Digital Milli-Ohm Meter

DESCRIPTION PAGE

SAFETY RULES.................................................... 01

GENERAL DESCRIPTION.................................... 02-03

FRONT PANEL LAYOUT....................................... 04

PREPARATION FOR USE.................................... 05

PRELIMINARY CHECKS...................................... 05

PRECAUTIONS..................................................... 06

MEASURING......................................................... 07

SIMPLIFIED MEASUREMENT.............................. 08

APPLICATIONS..................................................... 09

TEST LEADS......................................................... 10

THERMAL EFFECTS............................................ 11

FUSES REPLACEMENT....................................... 12

INPUT LIMITS & PROTECTIONS......................... 13

SPECIFICATIONS................................................. 14

SPARES & ACCESSORIES.................................. 15

LIMITED ONE-YEAR WARRANTY

CLEANING & STORAGE...................................... 16

BATTERY & FUSE REPLACEMENT..................... 16

SERVICE INFORMATION.................................... 17

........................ 15

SAFETY RULES

The meter has been designed with safety in mind. However, no
design can completely protect against incorrect use. Electrical
circuits are dangerous and lethal through lack of caution or poor
safety practice. The following rules should reduce the danger

• Read the User's manual carefully and completely before using
the instrument. Fully understand the instructions before using
this product. Follow the instructions for every test. Take all the
necessary precautions. Do not exceed the limits of this
instrument.

• The circuit to be tested must be de-energised and isolated before
connections are made to it.

• Do not use test leads, probes or crocodiles/aligators clips that
are dirty, damaged or have broken or cracked insulation. Such
accessories should be removed and repaired Immediately.

• Always disconnect the test leads before replacing any fuse
Always replace the fuse with the type specified and ensure that
they are correctly fitted.

• Double check the switch settings and leads connections before
measuring. Make a sketch to ensure proper operation and
principle of measurement is correct and well understood.

• Do not touch any exposed wiring, connections or other "live"
parts of an electrical circuit. If in doubt, check the circuit first for
voltage before touching it.

• This instrument should only be used by a competent,
suitably trained person which understand fully this test &
measurement procedure.

Warning, risk of electric shock.

Caution, refer to this manual before using the Meter.

-1-

GENERAL DESCRIPTION

The meter digital milli-ohmmeter is a battery operated instrument
wich supply a low current to the circuit under test, with which, stable,
accurate measurement of low resistance can be made, still, over a
wide range of values.

Resolution on the lowest range is 100µ ohm and on the highest
range, 1 ohm.

The meter has 5 measuring ranges, from 200.0milli-ohm to 2000
ohms.

Measurements are displayed on a 3½ digit custom liquid crystal
display with large digits.

This instrument is powered from batteries only ( alkaline or
rechargeable equivalent).
It has a regulated DC constant current source with current of 1mA
10mA and 100mA.

The instrument supply that current to the resistance being measured
through the C and C terminals (C being +, C being -).

1 2 1 2

The voltage drop across the resistance under test is measured by
the potential terminals P and P (P being +, P being -).

Should the current regulation drops out, the R Led will lit, indicating

1 2 1 2

C

that the resistance in the current circuit is too high. (Lowering the
current by selecting a higher resistance range can solve the
regulation.)

Should the R Led lit, that mean that the voltage measured on the

P

resistance is too high, and therefore over-range.

The resistance is measured precisely when the R and R Leds do

P C

not lit. If anyone of these leds lit, then the measurement can be
inaccurate.

-2-

The meter has a built-in custom 3½ digit liquid crystal display can be
viewed in most lightning conditions. This display indicates the
diferentes conditions (Hold, m, buzzer, polarity condition of load, +
or -, automatic decimal point change).

The ranges are selected by a 5 position rotary switch, and a test is
initiated by pressing the ON push-button.

The instrument takes measurements for 10 seconds if the "ON"
"TEST r " presentative" button is depressed for less than 2 seconds.

e

If the same push button is pressed for more than 3 seconds, the test
will carry on for 60 seconds.

The tester switch "OFF" completely when the rotary switch is in the
"OFF" position.

The tester "Hold" the last reading before stopping the test.
The tester is fuse protected and has a crowbar between C and C .

12

This crowbar is activated by voltage. If the voltage is too high, that
crowbar will blow the fuse automatically to interrupt the circuit.

The voltage between P and P is also protected for over voltage but

12

does not have a fuse.

The tester has a temperature shut down. The temperature sensing
is done on the current regulation transistor.
Should this over-temperature let lit, allow the instrument to cool
down for a while before proceeding further.

-3-

FRONT PANEL LAYOUT

If NO TEST LED lit, the current source is stopped.

Over Temperature indicator. Lit = Over-temperature or test

NO

TEST

R

R

stopped.

P

Resistance between the current leads too high (fuse!).

C

Resistance between the potential leads too high.

Current Injection

Terminals

Potential Injection

Terminals

C

MICROPROCESSOR CONTROLLED

AC

DC

P

1

HOLD

1

MAX MIN

MAX. DC20V

AUTO-HOLD

Hz

mV

kMW

kA
ms

DIGITAL MILLIOHM METER

Current/Range Table

Liquid Crystal Display

Rotary Selector Switch

Meet LVD & EMC

requirements

P

2

C

Test Current Range

10mA

10mA
100mA
100mA

2000

200.0

20.00

2000m

200.0m

TEST R

2

W

2000

1mA

OFF

ON

200.0

20.00

2000m

200.0m

P

W

W

W

W

EnerSaveTM

Ÿ Short Test duration if TEST
is depressed for less than
2Sec.
Ÿ Long Test Duration if TEST
is depressed for more than
3Sec.

Start/Stop Test

NO

TEST

R

R

P

C

-4-