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
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.
Ordering Information
DMS-EB-AC/DC
RN-DMS
AC power supply board
Resistor accessory kit for DMS-30 meters
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,
2
100-264Vac POWER SUPPLY BOARD FOR DMS-30 METERS
DMS-EB-AC/DC
SG10
12
SG14
1
SG7
SG8
DP4
SG13
SG12
SG4
SG6
SG11
R3
SG9
TB1
TB2
SG3 (DP3)
SG2 (DP2)
SG1 (DP1)
1
HI(+)
2
LO(–)
1
AC LO
2
AC HI
Figure 2. DMS-EB-AC/DC Board
Applications
1. Decimal Point Placement:
DATEL ships the DMS-EB-AC/DC with all
decimal point solder gaps (SG1, SG2, SG3 and SG4) open. To enable a
specific decimal point, close its respective solder gap with solder. When
reassigning decimal places for subsequent applications, remember to
open any previously closed solder gaps.
Close SG1 for 1.999 (DP1)
Close SG2 for 19.99 (DP2)
Close SG3 for 199.9 (DP3)
Close SG4 for 1999.9 (DP4 on DMS-40LCD)
2. Span (Gain) and Zero (Offset) Adjustments
(See Figure 3): DATEL
offers a resistor accessory kit, part number RN-DMS, consisting of 20-
turn potentiometers R4 (2K Ohms) and R5 (50K Ohms) and leaded
resistor R3 (10.5K Ohms). However, the leaded resistor supplied with the
RN-DMS accessory kit is not needed with the DMS-EB-AC/DC since it
contains a factory-installed 10.5K Ohm chip resistor. Once installed,
these potentiometers permit the span and/or zero adjustments described
in the following sections. R4 provides span adjust, while R5 applies a
positive offset to the meter’s (–) IN LO input.
Using Potentiometer R4 for Span Adjustment (DMS-30PC and DMS-
30LCD Meters Only)
1. For DMS-30-1, -2, and -3 models (+/-2V, +/-20V, +/-200V ranges):
Configuring the DMS-EB-AC/DC for span adjustment is simply a matter
of installing potentiometer R4, opening SG13, and then closing SG8,
SG11, and SG12.
2. For DMS-30-0 models (+/-200mV ranges): Span adjustment requires that
you open SG8, SG11 (if closed) and SG13 and then close SG7, SG9
and SG12. Then install R4.
Adjust span as desired. DMS-30-1, -2, and -3 span adjustment range is
typically +10% and –5%. The DMS-30-0 has a much wider span adjust,
however, it should be limited to ±10% for optimum accuracy and stability.
Using Potentiometer R5 to Apply a Positive Offset to Pin 12 (-) IN LO
1. Open SG14 and close SG6.
2. Install 50K potentiometer R5.
Potentiometer R5 applies a stable, positive dc-offset voltage to the
meter’s IN LO terminal. This offset voltage has a range of 0 to +1.2Vdc,
measured with respect to TB1 terminal 2 (LO). It can be used to null (or
cancel) the effects of an input whose zero level is not exactly zero volts.
For example, adjusting R5 allows the display to read “000” with an input
whose lowest level is slightly above zero volts. Please note, R5 can not
compensate for inputs whose zero level is negative (i.e., if TB1 HI is
more negative than TB1 LO).
3. Measuring Input Voltages Greater than 1.999Vdc
(Use DMS-30-0 or
DMS-30-1 Only): If possible, the resistors used for R1 and R2 should be
±1% metal-film types with TCR’s less than or equal to 100ppm/°C. More
information on selecting 1% resistors can be found in Application Note 14
of the DATEL Panel Meter Catalog.
CAUTION: Do not apply inputs greater than +/-250Vdc.
1. Open SG10. For applications in which input voltages exceed ±100Vdc,
also cut the 2 adjoining traces.
2. Configure the DMS-EB-AC/DC for span adjust using the procedure
previously outlined.
3. Calculate values for R1 and R2 as follows:
A typical value for R1 is 1M? . The sum of R1 + R2 should be between
50k? and 10M? .
R2 = (FSI x R1) / ( |Vin| - FSI)
Where:
FSI = The attenuated voltage between the meter’s (–) IN LO and (+) IN
HI pins (pins 12 and 11, respectively) needed to achieve the desired
display readings
Vin = Input signal at TB1 terminals 1 and 2, disregarding polarity
Example
Using a DMS-30-1 meter (+/-2V range), Vin is 0-5Vdc and the display
reading must be “000” to “1500”
1. Assume R1 = 1.0M?
.
2. R2 = (FSI x R1) / ( |Vin| - FSI)
R2 = (1.500 x 1,000,000) / (5.0 - 1.500)
R2 = 428,571? or 432k?
3. Calibrate the meter using a known voltage source. Adjust R4 to
compensate for tolerances in R1 and R2.
3
DMS-EB-AC/DC
100-264Vac POWER SUPPLY BOARD FOR DMS-30 METERS
Applications
4. DC Current Measurements
(Use +/-200mV Range DMS-30-0 Meters):
When using R2 location for a dc current-shunt, please note that the pc-
board copper traces which short out R1 can only carry currents up to
0.2A (200mA). However, dc currents up to 2A can be accommodated if a
20AWG jumper wire is soldered in location R1. Be sure R2 has a
sufficient power rating to safely carry the full load current. Refer to DMS
Application Note 6 for more information on dc ammeters.
1. Install R2: R2 = FSR / (I
MAX
. x 10000) where FSR is the desired meter
reading (0 up to 1999, disregarding any decimal points), and I
MAX
is
current in Amperes.
2. Configure the DMS-EB for span adjust using the procedure previously
outlined for the DMS-30-0 (+/-200mV range).
3. Apply the input signal (current) to TB1 (+) HI and (–) LO.
4. Adjust R4 for desired full scale readings.
5. Enable the appropriate decimal point using SG1, SG2, or SG3.
Example
Using a DMS-30-0 meter, a 0.100 Ampere input must read “100.0” mA on
the display.
R2 = 1000 / (0.1 x 10000)
R2 = 1 Ohm
Enable DP3 via SG3 for a display reading of “100.0”.
12
R5
R1
SG10
SG14
12
R2
SG14
SG7
SG8
SG4 DP4
SG13
R4
SG6
SG11
R3
SG12
SG9
TB1
SG7
SG8
SG4 DP4
SG13
SG12
SG6
SG11
R3
SG9
TB1
1
HI(+)
2
LO(–)
1
HI(+)
2
LO(–)
Figure 3. R4 and R5 Installation
Figure 4. R1 and R2 Installation
®
®
ISO 9001
REGISTERED
www.datel.com
DS-0341B
09/02
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: (508) 339-3000 (800) 233-2765
Fax: (508) 339-6356
Internet: www.datel.com
Email: sales@datel.com
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01
DATEL GmbH München, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025
DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions
contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL,
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