Falcon HED281 Manual Del Usuario página 2

Introduction
• Low power consumption
• 5 or 9 volt dc operation (customer selectable)
• Annunciators for common engineering units and decimal point
• Auto-polarity
• 200mV full scale reading
In 5V mode each module generates its own -5V supply which enables it to measure signals with the same
common zero as the supply. Connections are brought out to enable the module to operate in various modes
including single ended, ratio measurement and differential. Different modes are selected by linking PCB
solder pads which are provided for the purpose.
Specification
Accuracy (±1 LSD)
Linearity
Sample Rate
Temperature Stability
Operating temperature
Storage temperature
Supply voltage (5V mode)
Supply voltage (9V mode)
Supply current
Backlight current (HED281/DPM951)
Backlight current (HED282DPM952)
Input impedance
Power Supply Selection
5 volt mode 9 volt mode
LK5 Open LK5 Shorted
LK6 Shorted LK6 Open
Internal Reference Voltage
The internal reference voltage (REF HI) is set by VR1.The voltage is factory set at 100.0mV but may be
trimmed to suit individual applications, eg. to compensate for the inaccuracy of external resistors when using
scaling configurations.
HED281/282 only:
This is a 9 turn pot for greatest accuracy.
Application Circuits (page 13)
Note:
In the application circuits, power is supplied on pins +V and 0V.
Caution:
Where the measurement voltage is referenced to the supply voltage (in either current or voltage applications)
the voltage on IN HI or IN LO must not exceed ±4.5V for 5V supply or ±3.5V for 9V supply.
Scaling Configuration
You can configure the HED282/DPM952 for different voltage ranges by soldering resistors in the positions
RA and RB. As supplied RA has a 0Ω resistor fitted. On the HED281/DPM951, RA and RB must be fitted
externally.
0.1% resistors are required to maintain an accuracy of 0.1%. This may be relaxed if an accuracy less than
this is required.
2
Min Typ Max Units
0.05 0.1 %
±1 LSD
3 per sec
30 ppm/°C
0 50 °C
-20 70 °C
3 5 7 Vdc
7 9 12 Vdc
2 mA
80 mA
160 mA
100 MΩ