PRODUCT DESCRIPTION
The EM32-1B is a 3 ½ digit LCD voltmeter which is designed to be panel mounted in most low and medium
volume applications. The meter features 8mm digit height, 3 decimal points, auto-polarity,auto-zero, 200mV full
scale reading and a very low current consumption. This product is designed so no soldering is required.
Connection is via screw terminals, and options are selectedvia jumper links. The module features a round metal
bezel, requiring a 32.5mm (1.28") diameter cut-out. It is secured with the nut provided. Protection from the front
to IP 67 / NEMA 4X standards is achieved by placing the rubber seal between the module and panel during
assembly.
FEATURES
• 8
• 200mV d.c. Full Scale Reading
• 3.5 to 6.5V or 7.5 to 14.0V Operation
•
• Selectable
• Requires 32.5mm (1.28") Diameter Cut-out
• IP67 / NEMA 4X Protected
mm (0.31") Digit Height
Decimal Points
Auto-zero and Auto-polarity
TYPICAL APPLICATIONS
• Panel Mount Instrumentation
• Process & Control
• Automotive
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 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).
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 100 ppm/°C
Supply voltage L1 in default configuration 3.5
150
Input leakage current (Vin = 0V) 1 10 pA
+
5.0 6.5** V d.c.
L1 re-configured 7.5 9.0 14.0** V d.c.
Supply current L1 in default configuration 500 A
L1 re-configured
A��
* To ensure maximum accuracy, re-calibrate periodically.
** Operation of the meter beyond the maximum supply voltage rating may cause permanent damage to the meter.
Unless otherwise noted, specifications apply at T =25°C, V =5Vd.c. (f =48kHz) and are tested with the module configured for floating input
mode.
A supply clock
EM32-1B
Round Hole Mounting LCD Voltmeter
ORDERING INFORMATION
Stock Number
Standard Meter EM32-1B
Martel Electronics Corporation Tel: 800-821-0023
© Copyright 2005 Martel Eectronics Corporation All trademarks are the property of their respective owners. P/N 000000000 Rev. x
PO Box 770 Email: sales@martelcorp.com
Londonderry, NH 03053 USA Web: www.martelcorp.com
DIMENSIONS
All dimensions in mm (inches)
EM32-1B
Round Hole Mounting LCD Voltmeter
DIMENSIONS
All dimensions in mm (inches)
1.5 (0.06)
1.7 (0.07)
Panel cut-out
38.0 (1.5)
32.5
(1.28)
32.0 (1.26)
23.5 (0.93)
15.0 (0.59)
5.5 (0.22)
3.0 (0.12)
DIMENSIONS
All dimensions in mm (inches)
Vref
1
8
A/D
Neg Rail
Generator
+
_
ILO
RLO
COM
RHI
IHI
V+ V-
V+
DP 3 2 1
CAL
FUNCTIONAL BLOCK DIAGRAM
EM32-1B
Round Hole Mounting LCD Voltmeter
J1
J2
ILO IHI V+ 0V
0V
DIMENSIONS
All dimensions in mm (inches)
PANEL MOUNTING
1.5 (0.06)
1.7 (0.07)
Panel cut-out
2 3 41
38.0 (1.5)
32.5
(1.28)
32.0 (1.26)
23.5 (0.93)
15.0 (0.59)
5.5 (0.22)
3.0 (0.12)
CONNECTIONS (rear view)
0 V
V +
I H I
I L O
J2
L1
J1
RB
RA
2 Martel Electronics Corporation EM32-1B
CIRCUIT DIAGRAM
EM32-1B
Round Hole Mounting LCD Voltmeter
J1
J2
7
IC2
7660
6
2
5
C2'
1.5uF
C1'
1.5uF
4
8
3
Ra
RB
0V
ILO
IHI
V+
L1
PIN FUNCTIONS
JUMPER LINKS
Solder LINK L1
0V Negative power supply to the meter.
V+ Positive power supply to the meter.
IHI Positive measuring input.
IHI must be no closer than 1.5V to either the positive or negative supply.
ILO Negative measuring input.
ILO must be no closer than 1.5V to either the positive or negative supply.
J1 Connects ILO to COM, when jumper link is fitted.
J2 Connects ILO to 0V, when jumper link is fitted.
CIRCUIT DIAGRAM
EM32-1B
Round Hole Mounting LCD Voltmeter
J1
J2
7
IC2
7660
6
2
5
C2'
1.5uF
C1'
1.5uF
4
8
3
Ra
RB
0V
ILO
IHI
V+
L1
Default configuration Re-configured
L1 L1
Solder Link L1 is used to select to power supply mode of the
EM32-1B.
With L1 in the default configuration, the module operates from a
3.5 to 6.5Vd.c. supply, and measurements can be made with
respect to power supply 0V.
When L1 is re-configured, the module operates from a 7.5 to
14.0Vd.c supply. The voltage being measured must then be
floating with respect to the meter's power supply.
EM32-1B Martel Electronics Corporation 3
SCALING
Two resistors Ra and Rb
may be used to alter the
full scale reading (FSR) of
the meter - see table. The
track across Ra must be cut
for on-board scaling. The
meter will have to be recalibrated by adjusting the
calibration potentiometer
on the rear of the module.
FSR Ra Rb
2V 910k 100k
20V 1M 10k
Vin 200V 1M 1k
2000V* 1M 100R
200 A 0R 1k
2mA 0R 100R
Iin 20mA 0R 10R
200mA 0R 1R
�
Voltage
Current
+
-
Ra
Rb
IHI
Vin or in
I
ILO
EM32-1B
*Ensure that Ra is rated for high voltage use.
Must use external scaling resistors (Do not cut track across Ra).
EM32-1B
Round Hole Mounting LCD Voltmeter
0 V
V +
I HI
I LO
J2
L1
J1
RB
RA
Cut track across Ra
for on-board scaling
SCALING
Two resistors Ra and Rb
may be used to alter the
full scale reading (FSR) of
the meter - see table. The
track across Ra must be cut
for on-board scaling. The
meter will have to be re-
calibrated by adjusting the
calibration potentiometer
on the rear of the module.
FSR Ra Rb
2V 910k 100k
20V 1M 10k
Vin 200V 1M 1k
2000V* 1M 100R
200 A 0R 1k
2mA 0R 100R
Iin 20mA 0R 10R
200mA 0R 1R
�
Voltage
Current
+
-
Ra
Rb
IHI
Vin or in
I
ILO
EM32-1B
*Ensure that Ra is rated for high voltage use.
Must use external scaling resistors (Do not cut track across Ra).
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.
EM32-1B
Round Hole Mounting LCD Voltmeter
5V supply operation (3.5 to 6.5V Meter Power Supply)
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 jumper link J1 is not fitted.
Ensure jumper link J2 is not fitted.
Measuring a current from a circuit which is
floating with respect to the meter's supply,
i.e. the current and the meter's power
supply are isolated from each other.
Ensure jumper link J1 is fitted.
Ensure jumper link J2 is not fitted.
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 jumper link J1 is fitted.
Ensure jumper link J2 is not fitted.
+3.5 to +6.5V
V+
IHI
ILO
0V
+
-
±200mV
0V
+3.5 to +6.5V
V+
IHI
ILO
0V
0V
Rb
I+
I-
+3.5 to +6.5V
V+
IHI
ILO
0V
+
-
±200mV
0V
L1 =
0 V
V +
I HI
I LO
J2
L1
J1
RB
RA
Cut track across Ra
for on-board scaling
SCALING
Two resistors Ra and Rb
may be used to alter the
full scale reading (FSR) of
the meter - see table. The
track across Ra must be cut
for on-board scaling. The
meter will have to be re-
calibrated by adjusting the
calibration potentiometer
on the rear of the module.
FSR Ra Rb
2V 910k 100k
20V 1M 10k
Vin 200V 1M 1k
2000V* 1M 100R
200 A 0R 1k
2mA 0R 100R
Iin 20mA 0R 10R
200mA 0R 1R
�
Voltage
Current
+
-
Ra
Rb
IHI
Vin or in
I
ILO
EM32-1B
*Ensure that Ra is rated for high voltage use.
Must use external scaling resistors (Do not cut track across Ra).
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.
EM32-1B
Round Hole Mounting LCD Voltmeter
5V supply operation (3.5 to 6.5V Meter Power Supply)
9V supply operation (7.5 to 14.0V Meter Power Supply)
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 jumper link J1 is not fitted.
Ensure jumper link J2 is not fitted.
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 jumper link J1 is not fitted.
Ensure jumper link J2 is fitted.
Measuring a current from a circuit which is
floating with respect to the meter's supply,
i.e. the current and the meter's power
supply are isolated from each other.
Ensure jumper link J1 is fitted.
Ensure jumper link J2 is not fitted.
Measuring a current from a circuit which is
floating with respect to the meter's supply,
i.e. the current and the meter's power
supply are isolated from each other.
Ensure jumper link J1 is fitted.
Ensure jumper link J2 is not fitted.
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 jumper link J1 is fitted.
Ensure jumper link J2 is not fitted.
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 jumper link J1 is fitted.
Ensure jumper link J2 is not fitted.
+3.5 to +6.5V
V+
IHI
ILO
0V
+
-
±200mV
0V
+7.5 to +14.0V
V+
IHI
ILO
0V
+
-
±200mV
0V
+3.5 to +6.5V
+7.5 to +14.0V
V+
V+
IHI
IHI
ILO
ILO
0V
0V
0V
0V
Rb
Rb
I+
I+
I-
I-
+3.5 to +6.5V
V+
IHI
ILO
0V
+
-
±200mV
0V
+3.75 to +7.0V
-3.75 to -7.0V
V+
IHI
ILO
0V
+
-
±200mV
L1 =
L1 =
0 V
V +
I HI
I LO
J2
L1
J1
RB
RA
Cut track across Ra
for on-board scaling
4 Martel Electronics Corporation EM32-1B
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