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

DMS-EB-AC/DC

Functional Specifications

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

Storage Temperature range

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 line-

operated 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.

Technical Notes

1. Soldering and Wiring: DATEL recommends the use of “no-clean”

solders when installing components or making modifications to the DMS-

EB-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 applica-

tions 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 Technical 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: Two 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 DMS-

40LCD 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 recom-

mended. Be sure the fuse is rated for the applied line voltage.

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