DMS-40PC ETC-unknow, DMS-40PC Datasheet - Page 3

• Manufacturer Part Number: DMS-40PC
• Description: 4 1/2digit, Led Display Precision, Miniature Digital Panel Voltmeters
• Manufacturer: ETC-unknow

6. Gain Adjust: There is a gain-adjust potentiometer on the back
7. Soldering Methods: All models in the DMS-40PC Series easily
8. Suggested Mating Connectors:
DMS-40PC Series meters are high-precision versatile devices that
can be used in many applications requiring a 0 to 19,999 count
digital display. The application circuits chosen for this section are
ones that have historically received many inquiries. Every attempt
has been made to ensure technical accuracy, and all of the following
circuits have been prototyped and tested to ensure functionality.
Please keep in mind, however, that real-world applications are
seldom as straightforward as the approaches presented here.
All inputs applied to DMS-40PC meters must be steady, dc values,
otherwise the input itself may cause display instabilities. Due to their
4½ digit resolution, DMS-40PC meters must be wired with greater
care than their 3½ digit counterparts. Correct power-supply and
input-signal wiring — an absolute must! — helps eliminate ground-
loop induced errors that show up as unstable display readings.
When an input signal, assumed to be exactly zero volts, has a 1mV
(0.001V) ground-loop induced offset, it is displayed as "0010" on a
±2V input-range meter! DATEL's new Digital Panel Meter Catalog
contains an application note describing power supply wiring and
ground loop avoidance techniques.
control over the location of the decimal point by employing drive
circuits that are capable of sinking a minimum of 20mA at
voltages less than +0.4 Volts.
of each meter. It has approximately ±150 counts of adjustment
range. Since these meters essentially have no zero/offset errors,
a gain adjustment is effectively an overall accuracy adjustment.
Though they may be performed at any point (except zero),
accuracy adjustments are most effective when performed with
higher level input signals.
withstand most common wave soldering operations. We
recommend, however, that you evaluate the effects your
particular soldering techniques may have on the meter's plastic
case and high-precision electrical performance. We recommend
the use of water-soluble solders and thorough cleaning
procedures.
Board mounted:
Hard wiring is preferable, however, you can exercise dynamic
Panel mounted:
Connector housing
Terminal type
Crimping tool
Wire size
Insulation diameter
Stripping length
Socket
4 ½ D I G I T , L E D D I S P L A Y D I G I T A L P A N E L V O L T M E T E R S
Applications
DATEL P/N 39-2079400
DATEL P/N 39-2099090
DATEL P/N 39-2099000
22 to 26 AWG
0.062" (1.57mm) maximum
0.100 to 0.125" (2.54 to 3.17mm)
DATEL P/N 39-2359625
3
The DMS-40PC's simplified schematic, shown in Figure 1, can be
very useful when debugging a malfunctioning circuit, especially if
the user has some knowledge of operational amplifiers (op amps).
The meter's high-impedance input consists of an op amp powered
from a ±5Vdc power supply (the –5V is internally generated). Figure
1 shows that input signals applied to (–) INPUT LO and (+) INPUT
HI must to be kept within the ±5V power-supply rails. Also note that
only pin 11 has a current-limiting 909k series resistor. High input
voltages that have a common ground connection with pin 3 (5V
RETURN) should only be applied to pin 11 ((+) INPUT HI) and never
to pin 12. In these high-voltage cases, pin 12 should always be tied
to pin 3 (5V RETURN).
One of the simplified schematic's more noteworthy features is that it
shows some DMS-40PC internal voltage values and also that pin 3
is the meter's zero-volt reference point — regardless of the type of
power or signal source used. This is an important point to keep in
mind when using digital multimeters to perform system-level
measurements. The multimeter's negative lead (usually the black
one) must always be connected to pin 3 (5V RETURN). This is the
only way accurate readings can be made, particularly if the meter is
configured for a differential input and concerns arise regarding
common-mode voltages.
1. Single-Ended Input Configurations: The DMS-40PC can
measure single-ended signals with either positive or negative
polarities. True single-ended inputs always have one of their two
terminals at the same potential as the DMS-40PC's 5V RETURN
(pin 3). Single-ended inputs are usually derived from power
supplies that have a common ground with the meter’s +5V
supply. Figure 2 shows the recommended connections to be
used with this type of input. Pin 12, (–) INPUT LO, is shown
directly tied to ground. This connection to ground must be a
separate wire or pc-board trace originating at V
terminal. This hook-up will normally eliminate display instabilities
and errors caused by ground-loop currents which can occur if
(–) INPUT LO is tied to ground at, or near, pin 3.
8 5 - 2 6 4 V a c
+
–
V
I N
Figure 2. Single-Ended Input Configuration
A C t o D C C o n v e r t e r
D M S - P S 1 - C M
D A T E L
( – ) I N L O
( + ) I N H I
1 1
1 2
+ 5 V S U P
1
D M S - 4 0 P C - 1 - G S
6
D P 1
IN
's negative
DMS-40PC
3
5 V R E T