Figure 1. DMS-30DR Simplified Schematic

PATENT PENDING

D I G I T A L P A N E L M E T E R S

DMS-30DR Series

Daylight Readable, 3½ Digit Panel Meters

with Auto-Dimming LED Displays

www.cd4power.com

FEATURES

■

Super-bright LED displays are readable in

direct sunlight!

■

Autodim circuitry automatically adjusts

display brightness

■

Includes external brightness adjustment

■

Large (0.56”/14.2mm) easy-to-read red

LED display

■

High reliability alternative to LCD displays

■

Ideal for automotive, industrial, and marine

applications

■

Encapsulated package mounts in panels or

pc-boards

■

Miniature housing: 2.17” x 0.92” x 0.56”

(55mm x 23mm x 14mm)

■

4 differential input ranges provide ±1 count

accuracy

■

Single +5V supply; Less than 1-Watt power

consumption

■

0 to +60°C operating temperature range

+1.225V REFERENCE OUT

(+) INPUT HI

(–) INPUT LO

ANALOG

COMMON

REFERENCE OUT

REFERENCE IN

+5V SUPPLY

R1

DP 1

DP 2

DP 3

6

5

4

9

11

12

10

8

7

1

3

2

EXTERNAL BRIGHTNESS

ADJUSTMENT

5V RETURN

+5V

–5V

+5V

1.225V

REF.

R2

DATA

909k

R2 is not used on ±200mV (-0) models or ±2V (-1) models.

R2 = 100k on ±20V (-2) models and 9.1k on ±200V (-3) models.

0 Vdc

0.01µF

1.82k

(1)

(1)

LIGHT

SENSOR

DC/DC

CONVERTER

CONVERTER

A/D

–5V

+5V

–5V

+5V

C&D Technologies’ new DMS-30DR Series are the first digital panel meters to offer LED

displays that are readable in direct sunlight—no special filters or shading devices are required.

Their Autodim circuit automatically adjusts the display’s brightness to suit viewing environments

ranging from total darkness to full, brilliant sunlight. A user-accessible brightness adjustment pin

enables custom intensity settings or display matching in multiple display applications. Washed

out, hard-to-read digital readouts are a thing of the past!

Until now, users whose instrumentation required daylight visibility had to settle for less

reliable LCD display technology. However, in order to remain legible in low ambient light, LCDs

require complex, power-hungry backlighting circuitry. And, these displays typically suffer from

very narrow viewing angles. In contrast, DMS-30DR Series LED-based displays’ power consump-

tion drops as ambient light decreases, and their viewing angle extends to nearly 180 degrees

vertically and horizontally.

All models operate from a single +5V supply, and draw as little as 7mA when operated in total

darkness—that’s less than 1/10 Watt. At maximum brightness power consumption is typically

less than 200mA (1 Watt). DMS-30DR voltmeters are available in four differential input voltage

ranges: ±200mV, ±2V, ±20V and ±200V. Input impedance is 1,000 megohms for the ±200mV

and ±2V inputs and 1 megohm for the ±20V and ±200V inputs. CMRR for all devices is 86dB,

and inputs are overvoltage protected to ±250V. Each meter incorporates a precision, ultra-stable

voltage reference and is factory calibrated prior to encapsulation.

The small size (2.17” x 0.92” x 0.56”) of DMS-30DR meters is achieved by integrating their

display, Autodim display drivers, light sensor, reference circuit, and A/D converter into in a rugged

epoxy-encapsulated assembly. The device’s 12-pin, component-like, DIP package is both vibra-

tion and moisture proof, making them ideal for harsh environments. Each package incorporates a

built-in color filter and bezel, and is easily mounted in either panels or pc boards.