DATEL DMS-EB-AC-DC Datasheet

Figure 1. DMS-EB-AC/DC Simplified Schematic Diagram

Features

®®

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

100-264Vac Power Supply

Accessory Board for

DMS-30PC/LCD Panel Meters

DMS-EB-AC/DC

· Allows meters to operate from 100
to 240Vac (50/60Hz)

· Screw-type terminal block connections

· Provides 1500V isolation between AC

supply and input signal

· Has prototyping features of the standard
DMS-EB board

· On-board solder gaps for decimal
point placement

· Same size as DMS-30/40 meters

2.02" (51.3mm)L x 0.82" (20.8mm)W

· Low cost

This low-cost accessory board provides an easy way of powering all DMS­30PC-X-RL (red low-power models only), as well as all DMS-30LCD and DMS-
40LCD (non-backlit, +5V-powered models only) panel meters from 100-264Vac
(50/60Hz). The on-board AC/DC converter provides an isolated +5Vdc to power the
meter’s electronics, while providing 1500Vac isolation between the AC supply and
the input signal being measured. Line power and input signals connect to two
rugged, screw-style terminal blocks (TB1 & TB2) permanently mounted on the
DMS-EB-AC/DC. This type of terminal block provides reliable mechanical connec­tions and eliminates the need for any extra wiring harness connectors.

The DMS-EB-AC/DC board includes provisions for installing several user­supplied components that are required when the meter must be scaled to display
non-standard input ranges. The DMS-EB-AC/DC has provisions for such common
applications as attenuation of high input voltages, gain (span) and offset (zero)
adjustments, and direct decimal point placement. The DMS-EB-AC/DC is compat­ible with all four input versions of the DMS-30 Series meters (±200mV, ±2V, ±20V
and ±200V). Solder gaps, conveniently placed on the board, are easily bridged or
cut to configure the board to meet each application’s specific requirements.

➁

➁

➂

➂

➀ Refer to Mechanical Layout drawing for components and

solder gap location.

➁ Components are user-supplied and not part of the

standard product.

➂ R4 and R5 are part of the resistor accessory kit RN-DMS

(see ordering information)

➃ SG5 is not used

Order on-line at www.datel.com

R3

R5

10.5k

50k

R4
2k

SG7

SG11

R 1

R2

SG10

SG14

SG6

SG9

SG8

SG4

SG12

SG3

SG2

SG1

( ) IN P U T L O

(+ ) IN P U T H I

ANALOG

COM MO N

+1.23V

REF. OUT

REF. OUT/DP4

REF. IN

+V

OUT

+V

IN

V

IN

V

OUT

DC/DC

CONVERTER

+





&

%



'

!

"

#

$





TB2

12 12

C losed solder gap

O pen solder gap

DP 3

DP 2

DP 1

5V
RETURN

+5V
SUPPLY

HI

(+ )LO( )

AC
LOACHI

TB1

SG13

NEW DESIGN!

Wider Operating Range

1500V Isolation, Easier T o Modify

100-264Vac POWER SUPPLY BOARD FOR DMS-30 METERS

DMS-EB-AC/DC

Functional Specifications

(TA = +25°C)

Ordering Information

DMS-EB-AC/DC AC power supply board
RN-DMS Resistor accessory kit for DMS-30 meters

AC Supply Voltage:

100 to 264Vac @ 47-68Hz

AC Supply Current @ 264Vac/60Hz

60mA, maximum

Isolation

1500Vac, minimum

Operating Temperature Range

0 to +60°C

Storage Temperature range

–25 to +75°C

Humidity

0 to 95%, non-condensing

Dimensions

2.02" (51.31mm)L x 0.82" (20.8mm)W x 0.60" (15.3mm)D

TB1 and TB2 Wire Size and Strip Length

Wire Size 16 to 22 AWG (solid or stranded)
Strip Length 0.25" (6.35mm)
Screw Torque 3.6 pound-inches (0.4Nm)
Rated Voltage 310Vac

Introduction

As shipped, the DMS-EB-AC/DC is configured for use with +5V-powered
DMS-30PC or DMS-30LCD 3½ digit meters using the meter’s internal
reference (SG13 is closed). This configuration is the most common and
works well for most simple voltage measurements. Please read all of the
following technical notes and perform any required modifications before
soldering the DMS-EB-AC/DC onto the host meter.

Many of the applications described below apply to both DMS-30 (3½ digit
resolution) and DMS-40 (4½ digit resolution) meters. However, Application 5,
installing the span (R4) and offset (R5) adjust potentiometers, can only be
used with DMS-30PC/LCD meters. Also note that some of the other
applications require the installation of R4 and R5. See Technical Note 4

when using the DMS-EB-AC/DC with DMS-40LCD meters.
!IMPORTANT! AC power must be disconnected from TB2 terminals 1

and 2

before making modifications or installing user-supplied

components on the DMS-EB-AC/DC board! In many applications, the

DMS-EB-AC/DC installation is subject to electrical-code requirements (for
example, the NEC in the USA). Fusing, grounding, wire gauges, and leakage
currents may be regulated items. Since the DMS-EB-AC/DC is a line­operated device, it presents a shock hazard and should be installed only by
qualified personnel. Do not hesitate to contact DATEL if you have any
questions.

T echnical Notes

1. Soldering and Wiring: DATEL recommends the use of “no-clean”
solders when installing components or making modifications to the DMS­EB-AC/DC. Before mating the DMS-EB-AC/DC to the host meter,

ensure that modifications, if any, have been correctly made and that all
cut solder-gaps are fully open. Align pin 1 of the meter with pin 1 of the
DMS-EB-AC/DC, slide the board down flush to the meter’s housing and
solder all 12 pins. Lastly, carefully cut the meter’s 12 pins as close as
possible to the pc-board surface.

Making absolutely sure that the AC supply is de-energized (OFF),
connect the AC supply to TB2 terminals 1 (AC LO) and 2 (AC HI).
Connect the input signal being measured to TB1 terminals 1 (+HI) and 2
(-LO).

2. Grounding/Isolation: Because DMS-30 and DMS-40 meters are housed
in a plastic case, a connection to AC earth ground is not required. When
wired per the instructions above, the DMS-EB-AC/DC board provides a
minimum of 1500V isolation between its AC supply input (TB2) and its
input signal (TB1). However, please keep in mind that in many applica­tions the LO side of the input signal may be connected to AC ground
(i.e., earth ground) elsewhere in the system. Any Issues pertaining to

grounding and/or isolation of the DMS-EB-AC/DC power supply
board must be referred to qualified technical personnel.

3. Input Resistor Dividers (See Figure 4): Use 1%, or better, metal film

resistors for R1 and R2 in DMS-30 applications, and 0.5%, or better, in
DMS-40LCD applications. Make sure the resistor’s power and voltage
ratings are adequate for the given application. Using tight-tolerance
resistors in input scaling circuits allows most calibration adjustments to
be made with the meter’s internal rear-mounted potentiometers, through
the access holes provided (see T echnical Note 5 below).

4. DMS-40LCD Meters: The RN-DMS resistor accessory kit, comprised of
potentiometers R4 (Gain/Span) and R5 (Offset/Zero), cannot be used
with DMS-40LCD Series meters. However, to change the input range on
DMS-40LCD meters from the default low-range (i.e., with pin 2 of the
meter open) to the high range, short pin 2 to pin 1 (+5V) on the top right
side of DMS-EB-AC/DC board (refer to Figure 2 and the DMS-40LCD
data sheet for more information).

5. Calibration Potentiometer Adjustment Holes: T wo overlapping holes
on the DMS-EB-AC/DC provide access to the built-in ¾-turn calibration
potentiometer on DMS-30 meters or the 3-turn potentiometer on DMS­40LCD meters. The adjustment range of both pots is very narrow. See the
applicable product data sheet for more information on each meter’s
calibration potentiometers.

6. Solder Gap Identification (See Figure 2): Each solder gap’s respective
number is printed directly on the pc-board surface in copper etch. Be sure
to double check all solder gap modifications before applying ac power and
the input signal to the DMS-EB-AC/DC.

7. AC Supply Transients: The DMS-EB-AC/DC can withstand transients
typically found in instrumentation environments. Installations which
contain ac-powered equipment capable of generating large voltage and/or
current surges should use external energy-clamping devices. A 1500 Watt
bi-directional transzorb with a minimum stand-off voltage rating that
matches the highest line-voltage peaks will provide additional protection
under severe fault conditions. If a transzorb or other energy limiting device
is used, the ac supply feeding the DMS-EB-AC/DC should have its own
fuse. Refer to the fusing section for more information.

8. AC Supply Fusing: The DMS-EB-AC/DC board does not have an
internal fusing device. If required, a 0.2A slow-acting fuse is recom­mended. Be sure the fuse is rated for the applied line voltage.

2