DPM 3AS-BL 3‰ Digit Backlit LCD Voltmeter Module
PRODUCT DESCRIPTION
The DPM 3AS-BL features a 200mV d.c. measurement range with auto-zero and auto-polarity. Decimal points are user
selectable.
to its own power supply GND. The design
of the panel meter’s housing allows the module to be 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
• 11
• 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
The DPM 3AS-BL features a negative rail generator which enables the meter to measure a signal referenced
LED backlighting ensures excellent readability under low light conditions.
easily snapped into a panel. The module’s
mm (0.43") Digit Height
ORDERING INFORMATION
Stock Number
Standard Meter DPM 3AS-BL
ELECTRICAL SPECIFICATIONS
Specification Min. Typ. Max. Unit
Accuracy (overall error) * 0.1 % (–1 count)
Linearity –1 count
Sample rate 2.5 samples/sec
Operating temperature range 0 50 °C
Temperature stability 250 ppm/°C
Meter supply voltage V+ to GND configuration 3.0 5.0 7.5 V d.c.
Meter supply current V+ to GND configuration 350 A
Backlight supply voltage 4.75 5.0 *** V d.c.
Backlight supply current @ 5V d.c. 40 60 mA
Input leakage current (Vin = 0V) 1 10 pA
* To ensure maximum accuracy, re-calibrate periodically.
** 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 =25°C, V =5Vd.c. (f =48kHz) and are tested with the module configured for fully floating
input mode.
V+ to V- configuration 6.0 9.0 15.0** V d.c.
m
V+ to V- configuration
A supply clock
175 A
m
SAFETY
To comply with the Low Voltage Directive (LVD93/68/EEC), input voltages to the module’s pins must not exceed
60Vdc. The user must ensure that the incorporation of the panel meterinto 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.
PO Box 770, Londonderry, NH 03053 1-800-821-0023
E-mail: b4lascar@samsongroup.com.hk
www.martelcorp.com
DPM 3AS-BL 3‰ Digit Backlit LCD Voltmeter Module
DIMENSIONS
All dimensions in mm (inches)
Panel cut-out: 38.0 x 18.0
(1.50 x 0.71)
PANEL FITTING
Panel
Module
20.0 (0.79)
17.5 (0.69)
Panel thickness: 1.0 - 2.5
(0.04 - 0.10)
0.50 (0.02)
pin width
37.5 (1.48)
40.0 (1.57)
pin pitch
6.00 (0.24)
2.54 (0.1)
c
a b d
2.00 (0.08)
13.5 (0.53)
a. 2.00 (0.08)
b. 6.00 (0.24)
c. 1.60 (0.06)
d. 6.00 (0.24)
1
FUNCTIONAL BLOCK DIAGRAM
L-L+
8
1
COM
REF HI
REF LO
INHI
INLO
Vref
V+
CAL
+
_
A/D
V-TEST
BAT XDPGND
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.martelcorp.com
2
PIN CONFIGURATION (rear view)
11
LREF
BAT
XDP
TEST
CAL
L-
L+
12 13
V+
GND
COM
REF HI
REF LO
DP1DP2 DP3 BAT
1
V-
IN HI
IN LO
DPM 3AS-BL 3‰ Digit Backlit LCD Voltmeter Module
CIRCUIT DIAGRAM
8
V+
R10
100k
INHI
INLO
COM
REF HI
REF LO
GND
LREF
C1
R9
3k
3
47nF
220nF
2
4
R3
1.5k
100nF
6
5
7
C5C7C6
180k
47pF1u51u5
1
V-
13
L+
12
L-
R11
22R
27
28
29
C2
R1
180k
31
30
32
C4
34
33
36
35
38
39
40
R4
LED1LED2
INT
BUF
A/Z
IN HI
IN LO
COM
CREF+
CREF-
REF HI
REF LO
OSC3
OSC2
OSC1
V+
IC1
V-
1
5
a1
4
b1
3
c1
2
d1
8
e1
6
f1
7
g1
12
a2
11
b2
10
c2
9
d2
14
e2
13
f2
25
g2
23
a3
16
b3
24
c3
15
d3
18
e3
17
f3
22
g3
19
ab
20
POL
21
BP
TEST
37
26
R2
1M
Q1
BCX19
V+
a1
b1
c1
d1
e1
f1
g1
a2
b2
c2
d2
e2
f2
g2
a3
b3
c3
d3
e3
f3
g3
ab
POL
COM
LCD1
R5
100k
LOBAT
DP1
DP2
DP3
BAT
199.9
19.99
1.999
DP1
DP2
DP3
R71MR6
R8
1M
1M
11
BAT
10
XDP
9
TEST
PIN FUNCTIONS
1. V- Negative power supply to the meter (6.0 to 15.0V meter power supply applications only).
2. INLO Negative measuring input.
3. INHI Positive measuring input.
4. COM Ground for the analogue section of the A/D converter. It is actively held at 3.05V (nom.) below V+ and must not be
5. REFLO Negative input for reference voltage.
allowed to sink excessive current (>100 A) by, for instance, connecting to a higher voltage.
6. REFHI Positive input for reference voltage.
7. GND 0Vpower supply to the meter (3.0 to 7.5V meter power supply applications only).
8. V+ Positive power supply to the meter.
9. TEST Connect to V+ to test the LCD. Donot 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 beused to
power external logic up to a maximum of 1mA.
10. XDP Inversion of LCD drive voltage.
11. BAT Low Battery annunciator drive pin. See application on the right.
This pin is not fitted as standard.
12. L- Negative power supply to LED backlighting.
13. L+ Positive power supply to LED backlighting.
The backlighting is internally configured for 5V operation.
If a higher voltage is used, then add a series current limiting resistor Rs.
See Applications for calculations of Rs.
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 adda 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.
m
1M
1M
SET
THRESHOLD
BC 237
470k
Check Link BAT is OPEN.
4077
V+
8
V+
10
XDP
11
BAT
9
TEST
V-
1
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.lascarelectronics.com
www.martelcorp.com
DPM 3AS-BL 3‰ Digit Backlit LCD Voltmeter Module
SCALING
Two external resistors Ra
and Rb may be used to
alter the full scale reading
(FSR) of the meter - see
Voltage
(Vin) 200V 1M 1k
table. The meter will have
to be re-calibrated by
adjusting the calibration
potentiometer on the rear
of the module.
Current
I
( in) 20mA 0R 10R
*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. Taking any inputbeyond the power supply rails will damage the meter.
5V supply operation (3.0 to 7.5V Meter Power Supply)
FSR Ra Rb
2V 910k 100k
20V 1M 10k
2000V* 1M 100R
200 A 0R 1k
m
2mA 0R 100R
200mA 0R 1R
+
Vin or inI
-
Ra 1M
Rb
Input Filter
10nF
INHI
DPM 3AS-BL
INLO
+3.0 to +7.5V
+
–200mV
-
1M
10nF
3
2
4
5
8
V+
INHI
INLO
COM
REF LO
GND
7
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.
0V
+3.0 to +7.5V
3
2
4
5
V+
INHI
INLO
COM
REF LO
GND
7
–200mV
1M
+
10nF
-
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.
9V supply operation (6.0 to 15.0V Meter PowerSupply)
+3.0 to +7.5V
+
–200mV
-
-3.0 to -7.5V
1M
10nF
3
2
4
5
8
V+
INHI
INLO
COM
REF LO
V-
1
+6.0 to +15.0V
+
–200mV
-
1M
10nF
3
2
4
5
V+
INHI
INLO
COM
REF LO
V-
8
L+
if V+>5V then
Rs=(V+ - 5V)
13
12
L-
0.04
+3.0 to +7.5V
+
I
Rb
1M
10nF
I-
0V
3
2
4
5
INHI
INLO
COM
REF LO
V+
GND
8
7
0V
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.
8
L+
1
Rs=(V+ - 5V)
13
12
L-
0.04
0V
+6.0 to +15.0V
I
+
Rb
I-
1M
10nF
3
2
4
5
INHI
INLO
COM
REF LO
V+
V-
8
1
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.
DPM 3AS-BL Issue 4 December/2002 M.C. Applies to DPM 3AS-BL/5
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.lascarelectronics.com
www.martelcorp.com
4
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