LASCAR ELECTRONICS LTD.
MODULE HOUSE, WHITEPARISH,
WILTSHIRE SP5 2SJ UK
TEL: +44 (0)1794 884567 FAX: +44 (0)1794 884616
LASCAR ELECTRONICS INC.
3750 West 26th Street,
Erie, PA 16506 USA
TEL: +1 (814) 835 0621 FAX: +1 (814) 838 8141
LASCAR ELECTRONICS (HK) LIMITED
FLAT C, 5/FL., LUCKY FTY. bldg., 63-65 HUNG TO ROAD
KWUN TONG, KOWLOON, HONG KONG
TEL: +852 2797 3219 FAX: +852 2343 6187
1, 40. V+
Positive power supply.
2 -7, 12-14, 17, 38, 39 See SPECIAL NOTE: ANNUNCIATORS.
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.
Drive for "-" annunciator. Internally connected by link 11.
LCD backplane drive waveform.
19.99 See SPECIAL NOTE: ANNUNCIATORS.
Negative power supply.
Connect to required annunciators/DPs (see note).
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.
31. IN HI
Positive measuring input. Analogue inputs must be no closer than 1V to either the positive or negative supply.
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 (> 100µA) by connecting it directly to a higher voltage.
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.
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.
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.
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.
+ 31 IN HI
- 30 IN LO
Links 1, 2, 3 & 4 SHORTED.
Measuring a floating voltage
source of 200mV full scale.
31 IN HI
30 IN LO
Links 1, 3 & 4 SHORTED.
Split supply operation.
31 IN HI V+
Links 1, 2, 3, 4 SHORTED.
(supply MUST be isolated).
V1 - 30 IN LO
+ 36 REF HI
V2 - 35 REF LO
Measuring the ratio of two voltages.
Reading = 1000 V1/V2
30 IN LO
Links 1, 3 & 4 SHORTED.
Measuring 4-20mA to read 0-999
(supply must be isolated).
Specifications liable to change without prior warning
Applies to DPM 500/7