DPM 3AS-BL
PRODUCT DESCRIPTION
3‰ Digit Backlit LCD Voltmeter Module
The DPM 3AS-BL features a 200mV d.c. measurement range with auto-zero and auto-polarity Decimal points are user
.
selectable. The DPM 3AS-BL features a negative rail generator which enables the meter to measure a signal referenced
to its own power supply GND. LED backlighting ensures excellent readability under low light conditions. The design
of the panel meter’s housing allows the module to be easily snapped into a panel. The module’s low cost means it will
suit high and low volume applications. The DPM 3AS-BL is intended to replace the DPM 3, DPM 3S, DPM 3-BL and
DPM 3S-BL in many applications, usually requiring only minor circuit modifications.
FEATURES
• 11mm (0.43") Digit Height
• 200mV d.c. Full Scale Reading
• 3.0 to 7.5V or 6.0 to 15.0V Operation
• Auto-zero and Auto-polarity
• Programmable Decimal Points
• LED Backlighting
TYPICAL APPLICATIONS
• Precision Instrumentation Systems
• Power Supply Monitoring
• Hand held instruments
• Panel-Mount Indication
• Low Power Voltage Measurement
ORDERING INFORMATION
Standard Meter
Stock Number
DPM 3AS-BL
ELECTRICAL SPECIFICATIONS
Specification
Min.
Typ.
Max.
Unit
% (–1 count)
count
samples/sec
°C
ppm/°C
V d.c.
V d.c.
m
A
A
m
V d.c.
mA
pA
Accuracy (overall error) *
0.1
Linearity
–1
Sample rate
2.5
Operating temperature range
0
50
T
emperature stability
250
Meter supply voltage
V+ to GND configuration
3.0
5.0
7.5
V+ to V-
configuration
6.0
9.0
15.0**
Meter supply current
V+ to GND configuration
350
175
V+ to V-
configuration
Backlight supply voltage
4.75
5.0
***
Backlight supply current @ 5V d.c.
40
60
Input leakage current (Vin = 0V)
1
10
* T ensure maximum accuracy re-calibrate periodically
o
,
.
** Operation of the meter beyond the maximum supply voltage rating may cause permanent damage to the meter.
*** An external series resistor is required above 5V see Applications.
,
Unless otherwise noted, specifications apply at T
A
=25°C, V
supply
=5Vd.c. (f
clock
=48kHz) and are tested with the module configured for fully floating
input mode.
SAFETY
T comply with the Low V
o
oltage Directive (LVD 93/68/EEC), input voltages to the module’s pins must not exceed
60Vdc. The user must ensure that the incorporation of the panel meter into the user ’s equipment conforms to the
relevant sections of BS EN 61010 (Safety Requirements for Electrical Equipment for Measuring, Control and
Laboratory Use).
LASCAR ELECTRONICS INC.
E-mail: b4lascar@samsongroup.com.hk
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.martelcorp.com
DPM 3AS-BL
DIMENSIONS
All dimensions in mm (inches)
3‰ Digit Backlit LCD Voltmeter Module
pin pitch
6.00 (0.24)
2.00 (0.08)
0.50 (0.02)
pin width
a
b
c
d
20.0 (0.79)
17.5 (0.69)
40.0 (1.57)
2.54 (0.1)
37.5 (1.48)
13.5 (0.53)
a.
b.
c.
d.
2.00
6.00
1.60
6.00
(0.08)
(0.24)
(0.06)
(0.24)
Panel cut-out: 38.0 x 18.0
(1.50 x 0.71)
Panel thickness: 1.0 - 2.5
(0.04 - 0.10)
PANEL FITTING
Panel
Module
1
2
FUNCTIONAL BLOCK DIAGRAM
V+
L+
L-
PIN CONFIGURATION
(rear view)
Vref
CAL
COM
REF HI
REF LO
INHI
INLO
11
REF HI
IN HI
COM
GND
TEST
V+
XDP
REF LO
1
CAL
L-
IN LO
BAT
V-
LREF
DP2
L+
DP1
DP3
BAT
12
13
+
_
A/D
1
8
TEST
V-
GND
BAT
XDP
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.martelcorp.com
DPM 3AS-BL
CIRCUIT DIAGRAM
V+
8
R10
100k
3‰ Digit Backlit LCD Voltmeter Module
LREF
C1
47nF
27
INT
1
a1
b1
28
c1
BUF
d1
R1 29
A/Z
e1
180k
f1
31
IN HI
g1
30
a2
IN LO
b2
32
c2
COM
IC1
d2
34
e2
CREF+
f2
33
CREF-
g2
a3
36
REF HI
b3
c3
35
REF LO
d3
e3
38
OSC3
f3
39
g3
OSC2
ab
40
POL
OSC1
BP
V- TEST
37
26
V+
5
4
3
2
8
6
7
12
11
10
9
14
13
25
23
16
24
15
18
17
22
19
20
21
a1
b1
c1
d1
e1
f1
g1
a2
b2
c2
d2
e2
f2
g2
a3
b3
c3
d3
e3
f3
g3
ab
POL
COM
R9
3k
INHI
INLO
COM
3
2
4
R3
1.5k
C2
220nF
DP1
199.9
DP1
C4
100nF
LCD1
DP2
19.99
DP2
REF HI
REF LO
GND
6
5
7
C6
1u5
C7
1u5
R4
C5
47pF 180k
DP3
1.999
DP3
LOBAT
R8
1M
R7
1M
R6
1M
V-
1
V+
13
R11
22R
LED2
LED1
Q1
BCX19
R2
1M
R5
100k
BAT
11
BAT
L+
10
XDP
L-
12
9
TEST
PIN FUNCTIONS
1.
2.
3.
4.
5.
6.
7.
8.
9.
V-
INLO
INHI
COM
REF LO
REF HI
GND
V+
TEST
Negative power supply to the meter (6.0 to 15.0V meter power supply applications only).
Negative measuring input.
Positive measuring input.
Ground for the analogue section of the A/D converter. It is actively held at 3.05V (nom.) below V+ and must not be
allowed to sink excessive current (>100
m
instance, connecting to a higher voltage.
A) by, for
Negative input for reference voltage.
Positive input for reference voltage.
0V power supply to the meter (3.0 to 7.5V meter power supply applications only).
Positive power supply to the meter.
Connect to V+ to test the LCD. Do not connect to V+ for more than a few seconds as this may damage the LCD.
TEST is held actively at 5V (nom.) below V+ and is the ground for the digital section of the meter. It can be used to
power external logic up to a maximum of 1mA.
V+
8
4077
Inversion of LCD drive voltage.
V+
10
1M
1M
XDP
Low Battery annunciator drive pin. See application on the right.
11
BAT
This pin is not fitted as standard.
Negative power supply to LED backlighting.
9
Positive power supply to LED backlighting.
TEST
BC 237
The backlighting is internally configured for 5V operation.
470k
V-
If a higher voltage is used, then add a series current limiting resistor Rs.
SET
THRESHOLD
1
See Applications for calculations of Rs.
Check Link BAT is OPEN.
10.
11.
12.
13.
XDP
BAT
L-
L+
Note:
A negative supply is generated internally and mirrors the positive supply. For example: if V+ is +5V then the internally generated V-
,
is -5V When measuring with the input referenced to the same supply rail as that of the panel meter, then the limitations on the input
.
range are (V- + 1.5V) to (V+ - 1.5V).
Solder Links:
LREF
Normally Closed. Enables the internal voltage reference circuit. Cut this link when using an external voltage reference.
BAT
Normally Open. Disables the Low Battery warning annunciator. Cut this link and add a low battery detection circuit
to enable the Low Battery warning annunciator via Pin 11 (BAT).
DP1
Normally Open. Close this solder link to enable decimal point DP1.
DP2
Normally Open. Close this solder link to enable decimal point DP2.
DP3
Normally Open. Close this solder link to enable decimal point DP3.
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.lascarelectronics.com
www.martelcorp.com
DPM 3AS-BL
SCALING
T external resistors Ra
wo
and Rb may be used to
alter the full scale reading
(FSR) of the meter - see
table. The meter will have
to be re-calibrated by
adjusting the calibration
potentiometer on the rear
of the module.
Voltage
(Vin)
FSR
Ra
2V
910k
20V
1M
200V
1M
2000V* 1M
200
m
A
0R
2mA
0R
20mA
0R
200mA
0R
3‰ Digit Backlit LCD Voltmeter Module
Current
(
I
in)
Rb
100k
10k
1k
100R
1k
100R
10R
1R
Ra
+
1M
INHI
Rb
10nF
Vin or
I
in
DPM 3AS-BL
INLO
-
Input Filter
*Ensure that Ra is rated for high voltage use.
APPLICATIONS
Do not connect more than one meter to the same power supply if the meters cannot use the same signal
ground. T
aking any input beyond the power supply rails will damage the meter
.
5V supply operation
(3.0 to 7.5V Meter Power Supply)
+3.0 to +7.5V
8
+3.0 to +7.5V
8
+3.0 to +7.5V
if V+>5V then
Rs=(V+ - 5V)
0.04
8
V+
V+
V+
+
–200mV
1M
3
INHI
+
–200mV
1M
3
INHI
L+
L-
13
12
I
+
Rb
1M
3
INHI
10nF
-
10nF
2
INLO
4
COM
5
-
10nF
2
INLO
4
COM
5
REF LO
GND
7
2
INLO
4
COM
5
I-
REF LO
GND
7
REF LO
GND
7
0V
0V
0V
Measuring a single ended input
voltage referenced to supply i.e. the
,
input voltage and the meter’s power
supply share the same 0V rail.
Ensure solder link LREF is closed.
Measuring an input voltage referenced to
a floating supply i.e. the input voltage
,
and the meter’s power supply are isolated
from each other.
Ensure solder link LREF is closed.
Measuring a current from a circuit which is
floating with respect to the DPM’s supply
,
i.e. the current and the meter’s power
supply are isolated from each other.
Ensure solder link LREF is closed.
9V supply operation
(6.0 to 15.0V Meter Power Supply)
+3.0 to +7.5V
8
+6.0 to +15.0V
8
+6.0 to +15.0V
Rs=(V+ - 5V)
0.04
8
V+
V+
V+
+
–200mV
1M
3
INHI
+
–200mV
1M
3
INHI
L+
L-
13
12
I
+
Rb
1M
3
INHI
10nF
-
10nF
2
INLO
4
COM
5
-
10nF
2
INLO
4
COM
5
REF LO
V-
1
2
INLO
4
COM
5
I-
REF LO
V-
1
REF LO
V-
1
-3.0 to -7.5V
0V
0V
Measuring a single ended input
voltage referenced to supply i.e. the
,
input voltage and the meter’s power
supply share the same 0V rail.
Ensure solder link LREF is closed.
Measuring an input voltage referenced to
a floating supply i.e. the input voltage
,
and the meter’s power supply are isolated
from each other.
Ensure solder link LREF is closed.
DPM 3AS-BL
Issue 4
Measuring a current from a circuit which is
floating with respect to the DPM’s supply
,
i.e. the current and the meter’s power
supply are isolated from each other.
Ensure solder link LREF is closed.
M.C.
Applies to DPM 3AS-BL/5
December/2002
PO Box 770, Londonderry, NH 03053 1-800-821-0023
4
www.lascarelectronics.com
www.martelcorp.com
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