DPM
1AS-BL
PRODUCT DESCRIPTION
3½ Digit Backlit LCD Voltmeter Module
The
DPM
1AS-BL
features a 200mV d.c. measurement range with auto-zero and auto-polarity. Decimal points are user
selectable. The DPM 1AS-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 1AS-BL is intended to replace the DPM 1, DPM 1S, DPM 1-BL and
DPM 1S-BL in many applications, usually requiring only minor circuit modifications.
FEATURES
• 5.5mm (0.22") 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
1AS-BL
ELECTRICAL SPECIFICATIONS
Specification
Accuracy (overall error) *
0.1
Linearity
±1
Sample rate
2.5
Operating temperature range
0
50
Temperature 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.
15
30****
Input leakage current (Vin = 0V)
1
10
* 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.
**** This specification linearly derates to 20mA @ 50°C.
Min.
Typ.
Max.
% (±1 count)
count
samples/sec
°C
ppm/°C
V d.c.
V d.c.
µ
A
µ
A
V d.c.
mA
pA
Unit
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 single ended
input mode.
SAFETY
To comply with the Low Voltage 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).
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DPM
1AS-BL
DIMENSIONS
All dimensions in mm (inches)
3½ Digit Backlit LCD Voltmeter Module
30.0 (1.18)
28.0 (1.10)
a
b
c
d
14.0 (0.55)
11.0 (0.43)
0.50 (0.02)
pin width
2.00 (0.08)
pin pitch
5.00 (0.20)
1.26 (0.05)
Panel cut-out: 28.4 x 11.4
(1.12 x 0.45)
Panel thickness: 1.0 - 2.5
(0.04 - 0.10)
a.
b.
c.
d.
2.00
6.00
1.60
6.00
(0.08)
(0.24)
(0.06)
(0.24)
PANEL FITTING
Panel
Module
1
FUNCTIONAL BLOCK DIAGRAM
V+
BL-
2
PIN CONFIGURATION
(rear view)
Vref
CAL
LXDP
CAL
LCOM
GND
INLO
INHI
1
V+
10
DP1
DP2
DP3
XDP
INHI
INLO
+
_
A/D
1
8
V-
GND
DP3 2 1 XDP
BL-
V-
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page 2 of 4
DPM
1AS-BL
CIRCUIT DIAGRAM
3½ Digit Backlit LCD Voltmeter Module
PIN FUNCTIONS
1.
2.
3.
4.
V+
GND
V-
BL-
Positive power supply to the meter.
0V power supply to the meter (3.0 to 7.5V meter power supply applications only).
Negative power supply to the meter (6.0 to 15.0V meter power supply applications only).
Connect to the meter's negative supply voltage to switch on the LED backlighting.
For meter supply voltages above 5V, add a series resistor Rs.
See Applications for suitable circuit diagrams.
5. INHI Positive measuring input.
6. INLO Negative measuring input.
7. DP1
Connect to XDP to display DP1 (199.9).
8. DP2
Connect to XDP to display DP2 (19.99).
9. DP3
Connect to XDP to display DP3 (1.999).
10. XDP
Connect to pin 7, 8 or 9 to display required decimal point.
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:
LCOM
Normally Open. Connects INLO to COM.
LXDP
Normally Closed. Cut this link to disable the internal decimal point drive circuit and thereby
reduce the meter's current consumption.
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DPM
1AS-BL
SCALING
Two external resistors Ra
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.
FSR
2V
20V
200V
2000V*
200
µ
A
2mA
20mA
200mA
Ra
910k
1M
1M
1M
0R
0R
0R
0R
3½ Digit Backlit LCD Voltmeter Module
Voltage
(Vin)
Current
(
I
in)
Rb
100k
10k
1k
100R
1k
100R
10R
1R
+
Ra
INHI
Rb
DPM 1AS-BL
INLO
Vin or
I
in
-
*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 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
1
+3.0 to +7.5V
No DP
1
+3.0 to +7.5V
1
V+
V+
V+
+
±200mV
5
INHI
DP1
8
DP2
9
DP3
XDP
10
7
+
±200mV
5
INHI
BL-
4
I
+
Rb
5
INHI
-
6
INLO
GND
2
-
6
INLO
GND
if V+>5V then
Rs=(V+ - 5V)
0.015
I-
6
INLO
GND
2
0V
2
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 LCOM is open.
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 LCOM 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 LCOM is closed.
9V supply operation
(6.0 to 15.0V Meter Power Supply)
+3.0 to +7.5V
1
+6.0 to +15.0V
1
+6.0 to +15.0V
1
V+
V+
V+
+
±200mV
5
INHI
BL-
4
+
±200mV
5
INHI
BL-
4
I
+
Rb
5
INHI
-
6
INLO
V-
-
Rs=(V+) - (V-) - 5V
0.015
6
INLO
V-
3
Rs=(V+ - 5V)
0.015
I-
6
INLO
V-
3
-3.0 to -7.5V
3
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 LCOM is open.
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 LCOM is closed.
DPM
1AS-BL
Issue 3
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 LCOM is closed.
M.C.
Applies to DPM
1AS-BL/2
Page 4 of 4
Specifications liable to change without prior warning
February/2002
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