5 mm2) (can changed): 0,075 Ohm/m
Additional info:
max.
The calculation with the scheme below takes into account:
- The most distant slave situated the end the scheme -needs least: 19,2 VDC
- Line resistance (0. The supply current depends the voltage (typical values):
Supply voltage: 19.0
The power supply has always fused with max.2 31.2 V
Supply current typ.2006 PR0FIBUS-DP_PowerSupply-via-Bus-Cable_Calculation-Berechnung_05-2006.PDP21-FBP PROFIBUS DP-V0 FieldBusPlug
PDP22-FBP PROFIBUS DP-V1 FieldBusPlug
PDQ22-FBP
Power Supply via Bus Cable, Calculation
Supposed all devices are supplied externally, the supply has feed the PDP21, PDP22 PDQ22
connected the bus.
All slaves even the slave ost distant from the supply unit need supplied with min. PDP22, PDP21 mA
Supply current typ. (M12 System Limit)
Remark:
The max. 19. That means that the power supply unit the beginning the line has to
provide higher voltage compensate the voltage drops due the line resistance.
That means: For more than slaves additional segment (coupled with repeater) has be
provided that needs normally separate supply unit. number physical stations one bus segment 32, defined the RS-485 standard. output voltage above recommended supply unit V
FieldBusPlug 03.
In accordance with this fact the calculation below provides max slaves one master.xls PROFIBUS. PDQ22 mA
To simplify the calculation the scheme below uses the highest the currents but the other
hand does not regard the increased copper resistance and voltage drop for higher environment
temperatures.
Power Supply 24V adjustable Order code: 1SVR423416R0100 Type: CP-24/5.2
V including ripple. Normally
each repeater and RS-485 fiber-optic converter represent also one physical station each the
RS-485 bus line
