Flintec II PC-BASED - Manual (Page 9)

FlintWeigh Technical Manual, Rev. 3.03 November 2011 Page 9 of 32
4.3. Important Information about the Operation of Digital Load Cells
The connection of the digital load cells has to be done according the description in the KPFD-8 manual (see
Flintec-CD, technical documents, manuals).
It is allowed to connect up to 16 digital load cells (e.g. type RC3D) to the scale interface.
IMPORTANT: If you connect more than 10 digital load cells, then it is mandatory to power all load cells from an
external power supply.
External power supply for digital load cells
The external power supply has to provide a stabilized +12 V DC / ±5% with at least 1.5 A current. The input
goes directly to the connection cable of the digital load cells. Only the pins "RS485 A", "RS485 B" and "GND"
will be connected with the scale interface.
Fig. 4.4: Schematic of the external power supply to the digital load cells
4.4. Information about the Digital Inputs / Outputs
The digital I/O connections (one input, two outputs) can be used connecting e.g. a traffic light, a gate or a
switch-key.
Digital output:
2x, open collector (max. 24 V DC, max. 50 mA)
Digital input: 1x, opto-isolated, 3...24 V DC, max. 20 mA; min. switching current = 1,5 mA
Fig. 4.5 : Wiring example for the digital I/O
Pin 6
Pin 2
Pin 1
Pin 5
Pin 7
Pin 8
Weighing terminal
Junction
box
External power supply
+12V DC / 1.5 A
Digital load cells
Weighing
system controller