Falcon DPM 652 Handbuch Seite 2

Introduction
•Low power consumption
•9 volt DC operation
•Low battery warning
•Annunciators for common engineering units and decimal point
•Hold function
•Auto-polarity
•200mV–200V (DPM652), 200µA–2A(DPM752) full scale reading
Connector CN1
Pin Name Function
1 IN HI Positive measuring input
– No connection
2 IN LO Negative measuring input
Connector CN2
Pin Name Function
1 VDD Module DC positive supply +9V
2 VSS Module DC negative supply 0V
3 BL+ Backlight: connect with external resistor to +9V supply
4 BL- Backlight negative supply. Note: connect directly to OV not to pin 4
5 HOLD Connect to VDD to freeze display
Annunciators (page 7)
To display an annunciator, solder a connection between the required Annunciator solder pad and the
adjacent (Selected) solder pad. For the annunciators that are not in use, solder a connection between
BP
the associated Annunciator solder pad and the adjacent BP (Not Selected) solder pad to ensure that they
do not appear.
Application Circuits (page 8)
Scaling Configuration
The DPM 652 measures voltage, and the DPM 752 measures current. You can configure the units for a
number of preset ranges by connecting links to CN3 as shown on page 7. To configure the units for higher
ranges, extra scaling resistors must be fitted externally.
Analogue Inputs
IN HI and IN LO are all differential inputs. They respond to the voltage across them and not to the voltage
with respect to the power supply. There is a limit to the voltage which can be measured using a differential
input and this is known as the common mode range.
Caution:
No input may be taken outside the range VDD minus 0.5V and VSS plus 1.0v. If there is a danger that any
input may be taken outside these limits, it is necessary to fit a resistor of suitable value to limit the current to
100µA in series with the input or damage to the unit may occur.
The voltage between IN HI or IN LO must not exceed ±3.5V.
The maximum voltage allowed for any connection to the PCB is 200V. When measuring voltages
greater than 200V, the scaling resistors must be fitted externally.
Internal Reference Voltage
The internal reference voltage 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.
2
draft January 2007