Bulletin No. MDMV-F
Drawing No. LP0266
Revised 08/09
Tel +1 (717) 767-6511
Fax +1 (717) 764-0839
www.redlion.net
MODEL MDMV - MINIATURE DISPLAY MODULE D.C. VOLTMETER
LCD, POSITIVE REFLECTIVE OR NEGATIVE TRANSMISSIVE
WITH YELLOW/GREEN OR RED BACKLIGHTING
1 pA INPUT LEAKAGE CURRENT TYPICAL
200 mV FULL SCALE
AUTOMATIC ZEROING CIRCUIT
SELECTABLE DECIMAL POINTS
POLARITY INDICATION
5 VDC POWERED
FIVE SELECTABLE DISPLAY ANNUNCIATORS
PANEL MOUNT OR PC BOARD MOUNT
DESCRIPTION
The MDMV is a small panel or printed circuit board mount digital voltmeter.
With advantages of accuracy, size, and ease of installation, it is an ideal
replacement for analog meters. The unit has a 3½-digit LCD display with 0.4"
(10.2 mm) high digits. The displays are available in positive image reflective
(black digits, reflective background) or negative image transmissive (illuminated
digits, dark background) with red or yellow/green backlighting.
The integrated circuit is bonded directly to the printed circuit board and is
mechanically protected. Internal electrical interface connections use elastomeric
connectors to provide a corrosion resistant connection. This reliable construction
also reduces the space requirements.
The MDMV module is designed to operate from a +5 VDC supply. The
module measures input voltages from 0 to ±199.9 mV DC relative to the supply
common.
Auto-zeroing is provided by the module, therefore no zero adjustment is
required. If the input signal exceeds the input range, the unit display will
indicate an overrange condition.
The module has three selectable decimal point positions and five selectable
annunciators (BAT,V,A,m,μ). The BAT (Battery) annunciator is used to indicate
a low battery condition, while the others are used to indicate Volts and Amperes.
SPECIFICATIONS
1. DISPLAY:
3½-digit, 0.4" (10.2 mm) high digits. A minus(-) sign is displayed
when the voltage is negative.
2. DECIMAL POINTS:
Selectable decimal points are activated at the rear
terminal pins to allow the display to be read in tenths, hundredths or
thousandths.
3. ANNUNCIATORS:
5 selectable annunciators, BAT, V, A,
μ
and m are
activated at the appropriate rear terminal.
4. POWER REQUIREMENTS:
Reflective Versions:
3 VDC to 6 VDC @ 500
μA
Max.
Backlight Versions:
4.8 VDC to 6 VDC @ 25 mA Max.
5. INPUT RANGE:
0 to ±199.9 mV DC.
6. COMMON MODE:
±1 V min. around common.
7. ACCURACY:
±(0.1% + 1 digit).
8. RESOLUTION:
100
μv/Count.
9. OVERRANGE RATINGS, PROTECTION & INDICATION:
Max Input Voltage:
6 VDC Max.
Overrange Indication:
Overrange is indicated by a “1” displayed in the
most significant digit and the blanking of the three least significant digits.
10. READING RATE:
2½ readings per second.
11. RESPONSE TIME:
1.5 seconds to settle for a step input change.
12. INPUT LEAKAGE CURRENT:
1 pA typical, 10 pA Max.
Note: Recommended minimum clearance (behind the panel) for mounting clip installation is 2.25" (57.2)W x 1.5" (38.1)H.
PANEL MOUNT UNIT
PANEL CUT-OUT
DIMENSIONS
In inches (mm)
1.06
(26.9)
.93
+.03
-.02
(23.6
+.8
)
-.5
R .06 MAX., 4PL.
(1.5)
1.81 (46.0)
NOTE: BACKLIGHT MODELS: 0.50" (12.7)
REFLECTIVE MODELS: 0.31" (8.0)
.06
(1.5)
SEE
NOTE
.2 (5.08) MAX.
.14 (3.56) MIN.
1.68
+.03
-.02
(42.7
+.8
)
-.5
PRINTED CIRCUIT BOARD MOUNT UNIT
RECOMMENDED PCB LAYOUT
UNIT OUTLINE
.90
(22.9)
.19 (4.8)
1.65 (41.9)
NOTE: BACKLIGHT MODELS: 0.56" (14.2)
REFLECTIVE MODELS: 0.37" (9.4)
SEE
NOTE
.2 (5.08) MAX.
.14 (3.56) MIN.
.10 (2.5)
.12 (3.1)
Ø.042 (1.07)
THRU, 15 PL.
1
SPECIFICATIONS (Cont’d)
13. COMMON MODE REJECTION RATIO:
70 dB.
14. INPUT IMPEDANCE:
1000 M
15. TEMPERATURE EFFECTS:
Operating Range:
0 ° to 70 ° C
Storage Temperature:
-40 ° to 80 ° C
Temperature Coefficient:
100 ppm/ ° C
16. CONSTRUCTION:
High impact black plastic case. (Mounting clip
included with panel mount models.)
17. RELATIVE HUMIDITY:
Less than 85% RH.
18. WEIGHT:
Reflective Panel Mount:
0.76 oz (11 g);
Reflective PCB Mount:
0.54 oz (7.8 g)
Backlit Panel Mount:
0.96 oz (13.6 g);
Backlit PCB Mount:
0.75oz (10.4 g)
WIRING CONNECTIONS
The electrical connections are made via
terminal pins located on the back of the
unit. The terminal pins are on 0.100"
center lines and can be mated with the
RLC Model HWK7 cable assembly or
many standard 0.100" center line
connectors. When wiring the unit, refer to
Figure 3 to identify the wire position with
the proper function.
There are certain considerations that
should be observed when running the
signal wires. A length of wire can act like
an antenna, and the closer it is to a source
of electrical noise, the more it becomes
FIGURE 3
susceptible to that noise.
These are a few rules that should be followed when running these wires.
1. Never run signal wires in the same conduit or raceway with A.C. power lines,
conductors feeding motors, solenoids, SCR controls, heaters, etc.
2. Signal wires within enclosures should be routed as far away as possible from
contactors, control relays, transformers, and other noisy components.
3. When shielded wire is used, connect the shield to the common of the MDMV
unit, and leave the other end of the shield disconnected and insulated from
machine ground.
4. Connect common of the MDMV to machine ground at one point only.
INSTALLATION
The MDMV meters are available in either a panel mount or printed circuit
board mount design. The panel mount units are provided with a mounting clip
to securely hold the unit in the panel cutout.
Panel mount installation:
Cut panel opening to
specified
dimensions.
Remove burrs and clean
panel opening.
2. Install MDMV unit through
panel cutout as shown in
Figure 1.
3. Slide mounting clip over rear
of unit until clip is against
back of panel. The unit has
slots for the locking tabs to
hold it in the panel opening.
Note: Hold the MDMV front
bezel in place when sliding
the mounting clip in to
position.
1.
EXISTING PANEL THICKNESS
.031" to .125"
(.79 to 3.18)
LOCKING
TAB
PIN FUNCTIONS
+5 V
COMMON
COMMON
INPUT LO
-
-
-
-
BEZEL
INPUT HI
BACK PLANE
BACK PLANE
DP3
DP2
DP1
BAT
m
μ
V
A
-
-
-
-
-
-
-
-
-
-
-
MOUNTING CLIP
FIGURE 1
PCB mount installation:
1. Prepare printed circuit board hole pattern to the specifications.
2. Unit should be hand soldered using good soldering techniques and hand
cleaned if necessary.
+5 VDC Positive Supply Terminal.
Negative Supply Terminal.
Negative Supply Terminal.
Signal Input Low Terminal.
Normally connected to Common.
Signal Input High Terminal.
Back Plane Not Terminal. Any annunciator and/or
decimal point will appear when its terminal is
connected to this terminal.
Back Plane Terminal. Any annunciator and/or decimal
point NOT in use must be connected to this terminal.
Thousandths decimal point position.
*
Hundredths decimal point position.
*
Tenths decimal point position.
*
Low battery annunciator.
*
Milli annunciator.
*
Micro annunciator.
*
Volt annunciator.
*
Ampere annunciator.
*
MDMV SIGNAL INPUT
The MDMV signal input range is from 0 to ±199.9 mVDC with automatic
zero adjustment. Signal inputs are not floating. The calibration does not require
adjustment, since the unit has been calibrated at the factory.
If the input signal exceeds 200 mV, the module will go into an overrange
condition. The unit will display a minus sign when the input high terminal is
negative with respect to the input low terminal.
*
Note: All annunciators must be tied to either BACK PLANE or
BACKPLANE
HANDLING PRECAUTIONS:
This assembly contains electronic circuits
that are damaged by static electricity. Before handling the assembly,
discharge stray static electricity on your body by touching an earth ground
point. It is also important to handle the unit by the bezel assembly only.
Additionally, if it is necessary to handle a circuit board, be certain that hands
are free from dirt, oil, etc., to avoid circuit contamination that may lead to
malfunction.
BLOCK DIAGRAM
+5V
BACKPLANE
BACKPLANE
+5V
INHI
INLO
1MΩ
PROCESS
CIRCUITRY
CALIBRATION
POT
BATTERY
A
V
m
µ
DP1
DP2
DP3
COMMON
COMMON
FIGURE 2
Note: Incorrect supply polarity may permanently damage the unit.
2
A
V
µ
m
BAT
DP1
DP2
DP3
BACK PLANE
BACK PLANE
INPUT HI
INPUT LO
COMMON
COMMON
+5V
TYPICAL APPLICATIONS
The MDMV can be used in a wide variety of measurement applications. The
following circuits show some possibilities of the exceptional versatility of the
MDMV unit.
INHI
INPUT ATTENUATORS
To measure voltages greater than
200 mVDC, a voltage divider network
is needed. Shown at right is a typical
circuit.
V
IN
R1
R2
MDMV
PROCESS
CIRCUITRY
INLO
CURRENT MEASUREMENTS
Using a shunt resistor network, the MDMV voltmeter is capable of
displaying current.
200μA F.S.
2mA F.S.
20mA F.S.
200mA F.S.
IN
FIGURE 5
900
Ω
INHI
90
Ω
9
Ω
.9
Ω
INLO
.1
Ω
MDMV
PROCESS
CIRCUITRY
MULTI-RANGE MEASUREMENTS
200mV F.S.
900KΩ
90KΩ
9KΩ
1KΩ
2V F.S.
20V F.S.
200V F.S.
INHI
MDMV
PROCESS
CIRCUITRY
INLO
2A F.S.
V
IN
FIGURE 4
FIGURE 6
ORDERING INFORMATION
MODEL NO.
DESCRIPTION
PART NUMBER
To indicate various voltages in a multi-range application, it may be necessary
to switch the decimal point position and activate the appropriate annunciators.
This can be accomplished by connecting the appropriate annunciator terminals,
and the
back plane.
and the backplane terminals to a multi-position rotary
switch.
Panel Mount W/Reflective Display
PC Board Mount W/Reflective Display
MDMV
Panel Mount W/Yel-Grn Backlighting
Panel Mount W/Red Backlighting
PC Board Mount W/Yel-Grn Backlighting
PC Board Mount W/Red Backlighting
HWK7
MDM Cable Assembly
MDMV0000
MDMV0100
MDMV0010
MDMV0020
MDMV0110
MDMV0120
HWK70000
COLOR CODED RIBBON CABLE
STRIPPED AND TINNED
ACCESSORY: MDMV CABLE ASSEMBLY
.100 (2.54), TYP.
.100 (2.54), TYP.
CIRCUIT #1; BROWN
12 (305)
.15 (3.8)
3
LIMITED WARRANTY
The Company warrants the products it manufactures against defects in materials and
workmanship for a period limited to two years from the date of shipment, provided the products
have been stored, handled, installed, and used under proper conditions. The Company’s liability
under this limited warranty shall extend only to the repair or replacement of a defective product, at
The Company’s option. The Company disclaims all liability for any affirmation, promise or
representation with respect to the products.
The customer agrees to hold Red Lion Controls harmless from, defend, and indemnify RLC
against damages, claims, and expenses arising out of subsequent sales of RLC products or products
containing components manufactured by RLC and based upon personal injuries, deaths, property
damage, lost profits, and other matters which Buyer, its employees, or sub-contractors are or may be
to any extent liable, including without limitation penalties imposed by the Consumer Product Safety
Act (P.L. 92-573) and liability imposed upon any person pursuant to the Magnuson-Moss Warranty
Act (P.L. 93-637), as now in effect or as amended hereafter.
No warranties expressed or implied are created with respect to The Company’s products except
those expressly contained herein. The Customer acknowledges the disclaimers and limitations
contained herein and relies on no other warranties or affirmations.
Red Lion Controls
Headquarters
20 Willow Springs Circle
York PA 17406
Tel +1 (717) 767-6511
Fax +1 (717) 764-0839
Red Lion Controls
Europe
Printerweg 10
NL - 3821 AD Amersfoort
Tel +31 (0) 334 723 225
Fax +31 (0) 334 893 793
Red Lion Controls
India
54, Vishvas Tenement
GST Road, New Ranip,
Ahmedabad-382480 Gujarat, India
Tel +91 987 954 0503
Fax +91 79 275 31 350
Red Lion Controls
China
Unit 101, XinAn Plaza
Building 13, No.99 Tianzhou Road
ShangHai, P.R. China 200223
Tel +86 21 6113-3688
Fax +86 21 6113-3683
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