ANDERS ELECTRONICS DPM8100-2, DPM8100A-2, DPM8120-2, DPM8120A-2, DPM8140-2 Service Manual

digital panel modules user guide

DPM 8000 Series-2 Voltmeters and Ammeters

Models covered by this instruction sheet

DPM8100-2 3.5 DIGIT 200mV DC
DPM8100A-2 3.5 DIGIT 2V DC
DPM8120-2 3.5 DIGIT 200mV AC
DPM8120A-2 3.5 DIGIT 2V AC
DPM8140-2 3.5 DIGIT 200mV True RMS AC
DPM8400-2 4.5 DIGIT 200mV DC
DPM8400A-2 4.5 DIGIT 2V DC
DPM8420-2 4.5 DIGIT 200mV AC
DPM8420A-2 4.5 DIGIT 2V AC

The DPM8100-2 and DPM8400-2 series can be ranged as voltmeters or
ammeters by fitting multiplier or shunt resistors (not include into the
labelled positions on the main printed circuit board as shown on the
diagram overleaf. Wire links"JP1" may need to be removed for some
voltmeter ranges.

Using close tolerance resistors, the minimum of recalibration is required.
For accurate setting a calibrated supply should be used. The resistors
fitted should be adequately rated for the current or voltage range.

For non standard ranging and calibration, application sheet No. AES040
is available on request.

Over range is indicated by -1 on the display for 3.5 digit meters and by
flashing zero's on the 4.5 digit meters.

STEP BY STEP INSTRUCTIONS

Remove instrument from its protective plastic bag and clip off

1

front cover.

Pull off the three green safety terminals from the rear of the

2

meter. The complete panel meter assembly can now be
removed from its case by carefully levering the base of the
LED display board over the plastic retaining lug while pushing
gently on the terminal pins at the rear.

With reference to the Range Specification table and notes

3

overleaf, determine the resistance values to be fitted for the
required voltage or current range. Further note whether link
"JP1" should be removed.
Carefully de-solder and remove link JP1 if necessary and
solder the required resistors in place as shown on the main
circuit board diagram.

The decimal point should be set as required by either

4

repositioning the PCB jumper link JP2 on the 3.5 digit models
or setting a dip switch on the front of the 4.5 digit model, in
one of these locations:­DP1 gives 1.999 i.e. . XXX
DP2 gives 19.99 i.e. X. XX
DP3 gives 199.9 i.e XX. X
DP4 gives 1999.9 i.e XXX. X on 4.5 digit version only.

Slide panel meter back into its case along the guide rails

5

taking care to ease bottom of LED display board over
protruding lug. Then push the green safety terminals securely
back into place on the rear of the meter.

Make electrical connection to the meter with reference to the

6

Terminal Definition table. Note Mains Earth must NOT
connected to pin 4. There is no earth connection required
with this meter. Note also that Pin 3 is unused.

The instrument may now be tested.

7

For improved accuracy it can be adjusted by turning the
"span adj" potentiometer whilst applying full scale signal from
a calibrated source until exactly full scale is shown on the
display. On the DPM8140 and DPM8400 only, first set the
display to read zero for 0V input using the "offset"
potentiometer on the front left hand side of the board.

Finally, clip the cover back on and insert the meter into the

8

panel cut-out. "Snap" the mounting clips into the side of the
case (refer to installation diagram) and tighten the fixing
screws until secure in the panel - do not over tighten!

be

OPERATING SPECIFICATION

Accuracy: 81xx: +/- 0.1% of rdg +/-1 digit (AC models +/- 0.2%)

Line voltage: 115/ 230 volts +10, -20%, 50 - 60 Hz

Temperature: 0 - 50 degrees C

Humidity: below 85% RH

Power: 4VA

Sampling rate: 2.5 / second

84xx: +/- 0.01% of rdg +/-2 digits DC models
84xx: +/- 0.1% of rdg +/-3 digits AC models

TERMINAL DEFINITIONS

SYMBOL DESCRIPTION

1

2

3

4

5

6

7

8

9

IN HI

IN LO

n/c Not connected (unused)

Gnd (sig)

HOLD

(display)

+5V (o/p) internal +5V output (maximum 50mA)

230V

115V AC mains supply

0V (N)

DIMENSIONS

INSTALLATION DIAGRAM

Apply input to pins 1 and 2. If INLO signal is
greater than INHI the display will read -ive.

digital 0 Volts (NOT MAINS EARTH)

connect to terminal 6 (+5V) 8100 series
connect to terminal 4 (0V) 8400 series

DPM8000-2 Rev 3 10/03

PCB LAYOUT

SPAN

ADJUST

VR1

A to D Converter Chip

LINK

R17

JP1

R18

OFFSET
addition.

VR2

JP2

VR2

F1

1
2
3

Decimal point
DIP switch
on 4.5 digit
models

Zero offset
adjust (where
fitted)

Decimal point
select jumper
on 3.5 digit
models

Power supply
input fuse
100mA rated
(see Note 6)

NOTES

1

To measure voltages above the meters basic sensitivity, attenuator
resistors R17 and R18 need to be installed. The general equation to
determine their values is given by: V = V x (1 + R / R )
Where V is the input voltage required and V is the corresponding
display voltage. Note, V max is actually 199.9mV for a nominal

IN D

D

200mV basic sensitivity meter and 1.999V for a nominal 2V meter

Examples

VIN VDDisplay

19.99V

20V

1500rpm

10V

For standard input ranges choose the corresponding resistors from
the range specification table below.

2

For inputs greater than 200V, R17 must be a high voltage resistor
such as Philips VR37 Series (1x2M2, 0.5W, RS164-8316) with
R18=2k2 Alternatively, use two carbon film resistorsinseries,such as
Multicomp MCF (2x1M2, 0.5W, Farnell 262-195) with R18 as 2K4.
See the options for R17 below. The maximum input voltage on this
range with correct resistors is 650V.

3

For ranges of 200V or less, for R17,use metal film resistors, 1%, 0.5W
as Farnell 545-314. For basic 200mV use only existing link JP1

4

For R18, on all voltage ranges, use metal film resistors, 1%, 0.25W

5

On current ranges, usemetalfilmresistors, 0.5W for R30. The current,
using internal shunt resistor R30 must not exceed 2 Amps. Leave link
JP1 in place

IN D 17 18

17

R

1.999V

1.5V

1M

1M

R18
110K

176K

6

R30

123

N/c

In

InLo0vdcHold

Hi

!

Warning:

Make connection

no

from pin 4 to

under any

earth

conditions.

45 6

+5V

i/p

dc

mains

789

230

115

Vac

Vac0Vac

Important
Observe the mains
input connections

The power supply input protection fuse is a 20mm cartridge type rated
at 250V / 100mA.

200mV and

current

R17

Link JP1

RANGE SPECIFICATION

MODEL NUMBER R17

RESOLUTION

(of range required)

8100, 8120, 8140
8400, 8420

8100, 8120, 8140
8400, 8420

8100, 8120, 8140
8400, 8420

8100A, 8120A
8400A, 8420A

8100A, 8120A
8400A, 8420A

8100A, 8120A
8400A, 8420A

8100A, 8120A
8400A, 8420A

8100, 8120, 8140
8400, 8420

8100, 8120, 8140
8400, 8420

8100, 8120, 8140
8400, 8420

8100, 8120, 8140
8400, 8420

8100, 8120, 8140
8400, 8420

100 Vm

10 Vm

1mV

100 Vm

10mV

1mV
1mV

100 Vm

10mV

1mV

100mV

10mV

1V

100mV

0.1 Am

10nA

1Am

0.1 Am
10 Am

1Am

100 Am

10 Am

1mA

100 Am

BASIC

SENSITIVITY

200mV

200mV

200mV

2V

2V

2V

2V

200mV

200mV

200mV

200mV

200mV

RANGE

REQUIRED

0.2V

2V OUT

20V 1M

2V

OVERLOAD

PROTECTION

100V

100V

300V

100V

100V

300V

650V

(see note 2)

700V

200 Am

DO NOT

EXCEED

DISSIPATION

RATING OF

SHUNT

RESISTOR

RC

(SEE NOTE 5)

anders electronics plc Bayham Place, London NW1 OEU UK

Tel: [phone] Fax: [phone] http://www.anders.co.uk

Options for Resistor R17

Ranges below

200V

R17 R17

Metal film

resistor

R18 R30 LINK

WW

110K

1M

10K

110K20V

1M

2M2

10K200V

2K2

1M

1K

100R2mA IN

10R20mA IN

1R200mA IN

0R12A IN

Ranges above 200V

R17

Single Hi

Voltage resistor

W

JP1

IN

OUT

IN

OUT

OUT

OUT

IN

Solder

Two carbon

film resistors

INPUT

IMPEDANCE

>I00M

1M

IM

>I00M

IM

IM

2M2

Ik

IOOR

IOR

IR

R1 (0.1)

DP8000-2 Rev3 10/03

W