DATEL DMS-40PC Service Manual

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®®

DMS-40PC Series

4½ Digit, LED Display

Features

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Precision, autozeroing, factory-

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calibrated A/D converter

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Scientific-grade accuracy, ±2 counts

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Miniature size:

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2.17" x 0.92" x 0.56"
55mm x 23mm x 14mm

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Large (0.52"/13.2mm) LED display

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Choice of red, green or yellow colors

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High-intensity or low-power red

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LED's optional

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Single +5V supply (175mW for low-

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power models)

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Epoxy-encapsulated, 12-pin DIP with

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built-in color filter and bezel

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3 differential input voltage ranges

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DISPLAY HOLD and TEST functions

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Optional BCD data outputs for CPU

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interface

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0 to +50°C temperature range

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Actual Size

Precision, Miniature

Digital Panel Voltmeters

DMS-40PC Series, 4½ Digit, LED Display, Miniature DPM's are fully self-contained,
component-like, plug-in meters that provide scientific-grade accuracy (typically ±2
counts or ±0.005% of full scale) and outstanding reliability at a very affordable price.

Within its miniature (2.17" x 0.92" x 0.56"), epoxy-encapsulated package, each
meter contains a precision reference circuit; a high-resolution, autozeroing, factory­calibrated A/D converter; and a large (0.52"/13.2mm), easy-to-read, LED display.
LED's are available in red, yellow and green colors. Red LED's are also offered in
high-intensity or low-power versions.

The versatile design of the DMS-40PC Series assures trouble-free installation and
long-term operation. Differential input voltage ranges include ±2V, ±20V and ±200V.

Input impedance is a minimum 800kΩ. Non-inverting inputs are overvoltage protected

to ±250V, and CMRR is typically 86dB (dc to 60Hz).

The DMS-40PC's epoxy-encapsulated package has an integral bezel and color
filter. The moisture and vibration-proof package is extremely rugged and well suited for
harsh environments and extended temperatures. Devices are fully specified for
0 to +50°C operation.

All models operate from a single +5V supply and typically consume 500mW. Low­power models, whose display is just as bright as standard models, typically consume
175mW. DISPLAY TEST and HOLD functions are standard on each meter, and a
complete set of BCD outputs are optional for sending data to CPU's or remote
displays.

DC/DC

0 Vdc

+5V

–5V

CONVERTER

DATA

A/D

1

909k

R1

12

(–) INPUT LO

11

(+) INPUT HI

10

ANALOG
COMMON

9

DISPLAY HOLD

8

DP4

7

REFERENCE IN/OUT

V+

0.01µF

V–

2.5V
REF.

+5V

1

R2 is not used on ±2V (-1) models.
R2 = 101k on ±20V (-2) models and 9.2k on ±200V (-3) models.

R2

+5V SUPPLY

DISPLAY TEST

5V RETURN

DP 3

DP 2

DP 1

1

2

3

4

5

6

CONVERTER

Figure 1. DMS-40PC Series Simplified Schematic

DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: [phone] Fax: [phone] • Email: [e-mail] • Internet: www.datel.com

DMS-40PC

4½ DIGIT, LED DISPLAY DIGITAL PANEL VOLTMETERS

Performance/Functional Specifications

Typical at TA = +25°C and supply voltage = +5V using the single-ended input circuit,
unless otherwise noted.

Order on-line at www.datel.com

Analog Inputs Min. Typ. Max. Units

Full Scale Input Range:

DMS-40PC-1 -- ±2 -- Volts
DMS-40PC-2 -- ±20 -- Volts
DMS-40PC-3 -- ±200 -- Volts

Input Impedance:

DMS-40PC-1 100 1000 -- M
DMS-40PC-2, -3 0.8 1 -- M

Overvoltage Protection

Common Mode Voltage Range -- -- ±2 Volts

CMRR (dc to 60Hz) -- 86 -- dB

Control Inputs ➁

Decimal Point Placement (Pins 4-6, 8) Tie to pin 3 to activate

Display Test (Pin 2) Tie to pin 3 to activate all segments

Display Hold (Pin 9) Tie to pin 3 to hold last reading

BCD Outputs ➂

Logic levels (1 LSTTL load max.):

Logic "1" +2.4 -- -- Volts
Logic "0" -- +0.4 +0.8 Volts

Performance

Sampling Rate 2.5 samples per second

Accuracy (15 minute warm-up):

DMS-40PC-1 (VIN = +1.9V) -- ±2 ±3 Counts
DMS-40PC-2 (VIN = +19V) -- ±3 ±4 Counts
DMS-40PC-3 (VIN = +190V) -- ±3 ±4 Counts

Zero Reading (VIN = 0 Volts) "– 0001" "0000" "0001"

Temperature Drift (0 to +50°C):

DMS-40PC-1 -- ±0.4 ±1 Cnts/°C
DMS-40PC-2, -3 -- ±0.4 ±1.5 Cnts/°C

Power Supply Requirements

Supply Voltage +4.75 +5.00 +5.25 Volts

Supply Current:

Standard Models
Low-Power Models -- +35 +50 mA

Display

Display Type and Size 4½ Digit LED, 0.52"/13.2mm high

Polarity Indication Autopolarity ("–" for negative VIN)

Overrange Indication "– 0000" (flashing) for negative VIN

Physical/Environmental

Operating Temperature 0 -- +50 °C

Storage Temperature –20 -- +75 °C

Humidity (Non-condensing) 0 -- 95 %

Case Material Polycarbonate

Weight 0.75 ounces (21 grams)

➀

Applies for transient or continuous overvoltages applied to (+) INPUT HI (pin 11)
with (–) INPUT LO (pin 12) properly connected. Pin 12 is not overvoltage protected
(see Figure 1). Voltages applied to pin 12 should not exceed the supply voltage.

➁

See Technical Notes.

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BCD outputs are optional and must be specified in the part number.
See Ordering Information.

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Includes high-intensity and BCD-output models.

➀

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-- -- ±250 Volts

-- +100 +140 mA

"0000" (flashing) for positive VIN

Ordering Information

DMS-40PC - 1 - R S

LED Color:

Ω
Ω

BCD Output Models:

BCD outputs are only available on standard red meters.

DMS-40PC-1-RS-BCD for ±2V input range
DMS-40PC-2-RS-BCD for ±20V input range
DMS-40PC-3-RS-BCD for ±200V input range
DMS-40PC-1-RL-BCD for ±2V input range
DMS-40PC-2-RL-BCD for ±20V input range
DMS-40PC-3-RL-BCD for ±200V input range

Accessories:

DMS-PS1-CM +5V/1.0A AC/DC power supply module
DMS-30-CP Panel cutout punch
DMS-BZL1 DMS-40 bezel assembly
DMS-BZL2 DMS-40 bezel assembly with sealing gasket
DMS-EB Application/evaluation board with standard

A panel-mount retaining clip is supplied with each model.

Input Range:

1 = ±2V
2 = ±20V
3 = ±200V

MOLEX connector, decimal point solder pads
and attenuation resistor pads.

Technical Notes

1. ANALOG COMMON (Pin 10): This pin is an internal, low-noise
ground for the DMS-40PC. It is internally connected to pin 3
(5V RETURN). Do not connect pin 10 to either pin 3 or your
system ground as this will create a ground loop and possibly result
in erroneous readings.

2. REFERENCE INPUT/OUTPUT (Pin 7): This pin accesses the
meter's internal reference and is used during the factory calibration
procedure. Pin 7 should be left open in most common applications.
It can be used in certain "ratiometric" applications in which it is
desirable for the meter’s reference to track an external reference.
See Ap Note 3 in the DATEL Panel Meter Catalog for more details.

3. DISPLAY TEST (Pin 2): Connecting pin 2 to ground (pin 3, 5V
RETURN) will activate all LED segments, and the display will read
"–18888" regardless of the actual applied input. To reduce self­heating, the display should not be left in the "test" mode for

more than 10 seconds. This pin should be left open if unused.

4. DISPLAY HOLD (Pin 9): For normal operation, this pin should be

left open. To hold the meter’s last reading and display it continu­ously, tie pin 9 to ground (pin 3, 5V RETURN).

5. Decimal Point Placement: The location of the decimal point is
user-selectable, and the decimal point control pins (DP1-DP4) are
active low functions. Select the appropriate decimal point by tying
pin 4, 5, 6 or 8 to pin 3 (5V RETURN). Unused decimal point
location pins should be left open.

GS = Standard Green
RH = High-Intensity Red
RL = Low-Power Red
RS = Standard Red
YS = Standard Yellow

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