DPM 500
12.5mm (0.5“) Digit Height
Programmable Decimal Points
Auto-zero
Auto-polarity
200mV d.c. Full Scale Reading (F.S.R.)
Backlit Single Rail Version (DPM 500S-BL)
Annunciators
-
+
3½ Digit LCD Module
The DPM 500 uses advanced components and construction techniques to provide a uniquely compact unit. The meter is in a 40 pin
DIL integrated circuit format that can be plugged directly into a DIL socket or panel mounted using the snap in bezel. For single rail use,
the DPM 500S-BL features a built in negative rail generator, enabling the meter to measure a signal referenced to its own power supply
0V.
°
C
°
F
µA
mV
kΩ
MHz
SCALING
Standard Meter
Backlit Single Rail Version
Stock Number
Min.
Typ.
0.05
3
100
9
5
150
250
30
1
DPM 500
DPM 500S-BL
% (±1 count)
count
sample/sec
°C
ppm/°C
V
µ
A
Two resistors Ra and Rb may be fitted in order to alter the
full scale reading (F.S.R.) of the meter - see table.
Meter will need re-calibration.
Specification
Required F.S.R.
2V
20V
200V
2kV
200
µ
A
2mA
20mA
200mA
Note
Note
Note
Note
910k
1M
1M
1M
0R
0R
0R
0R
Ra
100k
10k
1k
100R
1k
100R
10R
1R
Rb
Accuracy (overall error)*
Linearity
Sample rate
Operating temperature range
Temperature stability
Supply
DPM 500
voltage
DPM 500S-BL
Supply current
DPM 500
(not inc. backlighting)
DPM 500S-BL
Backlight
Voltage
(DPM 500S-BL)
Current
Input leakage current (Vin = 0V)
Max.
0.1
±1
50
14
6.5
5
60
10
Unit
0
7.5
3.5
V
mA
pA
NOTE
Ensure link 10 is cut if fitting Ra.
CONNECTOR SOURCING GUIDE
METHOD
* To ensure maximum accuracy, re-calibrate periodically.
40 Pin DIL IC Socket
SAFETY
To comply with the Low Voltage Directive (LVD 93/68/EEC), input voltages to the module’s pins must not exceed 60Vdc. If voltages to the
measuring inputs do exceed 60Vdc, then fit scaling resistors externally to the module. The user must ensure that the incorporation of the
DPM into the user’s equipment conforms to the relevant sections of BS EN 61010 (Safety Requirements for Electrical Equipment for
Measuring, Control and Laboratory Use).
DIMENSIONS
All dimensions in mm (inches)
60.0 (2.36)
1.1 8.2
(0.04) (0.32)
45.0 (1.77)
a. DPM 500
6.7 (0.26)
DPM 500S-BL 12.1 (0.48)
b. 4.80 (0.19)
30.0 (1.18)
16.0 (0.63)
Panel cut-out = 57 x 27 (2.24 x 1.06)
Display in TEST mode
5.0
(0.19)
1
7
52 (2.05)
12
:
E3
~
a 4.0 (0.16)
20
9
11
20
8
24.8 (0.98)
15.2 (0.60)
V+
V
m
A
°F
°C
µ
8.5 (0.33)
+
40
21
V+
Ω
Hz
TEST
REF
HI
REF
LO
REF+
REF-
COM
IN HI
IN LO
BG
-5V
XDP
V-
DP1
DP2
DP3
XG3
BP
-
AB
POL
XB3
+
40
-
1
7
13 12
3
10
5
12
15
14
Rb
1
2
Ra
7
4
DPM 500S-BL ONLY
ON-BOARD LINKS
OPTIONAL SCALING
RESISTORS
M
K
-
b
21
PANEL FITTING
1.87
(0.07)
0.5
(0.02)
2.54
(0.1)
REAR VIEW
Fit the bezel to the front of the panel and locate the meter into the bezel from behind. Alternatively the meter and bezel may be assembled before
fitting to the front of the panel but care must be taken not to use excessive force. Finally fit the window into the front of the bezel.
Martel Electronics, Corp. P.O. Box 770 Londonderry, NH 03053
Toll Free: (800) 821-0023 Phone: (603) 434-1433 Fax: (603) 434-1653
1, 40. V+
Positive power supply.
2 -7, 12-14, 17, 38, 39 See
SPECIAL NOTE: ANNUNCIATORS.
15. -
Input for the polarity annunciator. Internally linked to POL (pin 20). If this is to be externally controlled, cut link 11.
16, 18, 19, 22
XB3, E3, AB, XG3. Outputs for use in auto-ranging applications.
20. POL
Drive for "-" annunciator. Internally connected by link 11.
21. BP
LCD backplane drive waveform.
23. DP3
1.999
24. DP2
19.99 See
SPECIAL NOTE: ANNUNCIATORS.
25. DP1
199.9
26. V-
Negative power supply. Note that if the DPM 500S-BL is being used, the voltage between V+ and V- must not exceed 6.5V.
27. XDP
Connect to required annunciators/DPs (see note).
28. -5V
Output from negative rail generator circuit. This output is an inversion of V+ (DPM 500S BL ONLY).
29. BG
Input for bandgap reference. (1.22V nom).
30. IN LO
Negative measuring input. Analogue inputs must be no closer than 1V to either the positive or negative supply. The negative
31. IN HI
Positive measuring input.
supply of the DPM 500S-BL is generated internally and mirrors the positive supply voltage.
32. COM
The ground for the analogue section of the A/D converter, held actively at 2.8V (nom) below V+. COM must not be allowed to sink
excessive current (> 100
µ
A) by connecting it directly to a higher voltage.
33. REF-
Negative output from internal reference.
34. REF+
Positive output from internal reference.
35. REF LO
Negative input for reference voltage.
36. REF HI
Positive input for reference voltage.
37. TEST
Connecting this pin to V+ turns on the segments as illustrated. It should not be operated for more than a few seconds as the DC
voltage applied to the LCD may "burn" the display. This pin is nominally at 5V below V+ and is the ground for the digital section
of the meter, it can be used as a negative supply to power external logic up to a maximum of 1mA.
40. V+/CLK Normally tied to V+ via Link 12 but can be used to over ride the internal oscillator and control the sample rate by cutting Link 12 and
making Link 13.
LED BACKLIT VERSIONS:
Apply 5V DC to the backlight tab on the side of the meter. Typical current is 30mA. For higher voltages, fit a resistor in series.
E.g. For 9V use 150R. Maximum current = 60mA.
.
SPECIAL NOTE: ANNUNCIATORS:
The DPM annunciators (DPs, °C, etc.) can be displayed by connecting them to XDP However as these
annunciators are normally ‘floating’, under certain conditions they may appear when not wanted. To suppress unwanted annunciators, link them to
the backplane (BP). If the annunciators are being switched, connect them via a 1M resistor to the BP (pin 21). The annunciators will then operate
normally when connected to XDP Ensure that an annunciator is not connected directly to the XDP and BP at the same time.
.
PIN FUNCTIONS
VARIOUS OPERATING MODES
ON-BOARD LINKS: In order to quickly and easily change operating modes for
different applications, the meter has several "on-board links". They are designed
to be easily opened(cut) or shorted (soldered).
Do not connect more than one meter to the same power supply if the meters cannot
use the same signal ground. Taking any input beyond the power supply rails will
damage the meter.
1
V+
V+
1
V+
31 IN HI
30
IN LO
Normally
SHORTED
Cut to
OPEN
Normally
OPEN
Solder to
SHORT
V+
1
V+
V+
+
±200mV
31
30
IN HI
IN LO
V-
26
+
±200mV
-
14V max
7V min
+
31
30
±200mV
IN
HI
IN
LO
-
0V
1V min
V-
26
-
V-
V-
Links 1, 2, 3 & 4 SHORTED.
V-
Links 1, 3 & 4 SHORTED.
0V
Links 1, 3 & 4 SHORTED.
26
Measuring a floating voltage
source of 200mV full scale.
V+
Split supply operation (DPM 500).
Measuring a single ended input
referenced to supply (DPM 500S-BL).
I
IN
V+
31
IN HI
V+
V
1
1
R
R= 0.2
I
FSR
1
V+
31
+
IN HI
30
-
IN LO
V+
1
V+
31
IN
HI
220K
30
IN LO
V
2
26
+
V-
V-
Links 1, 2, 3, 4 SHORTED.
REF HI
35 REF LO
-
V-
26
36
6R2
5K
30
32
IN
LO
V-
I
OUT
COM
V-
26
V-
Links 1, 3 & 4 SHORTED.
Measuring current
(supply MUST be isolated).
Measuring the ratio of two voltages.
Reading = 1000 V
1
/V
2
50mV< V
2
<200mV
V
1
<2V
2
.
DPM 500
Issue 4
July/1999
Measuring 4-20mA to read 0-999
(supply must be isolated).
Specifications liable to change without prior warning
M.C.
Applies to DPM 500/7
DIY/Open Source Hardware
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