power automation PA 8000 LW Series, Installation Instructions Manual, Page: 100 / 132

n Use the actual data obtained from the cable's technical
specifications.
n Double the cable's physical length.
This is necessary as there are two lines: one line to the
RMS (+5 V) and one line from the RMS (grounding).
n Calculate the voltage drop as follows:
Voltage drop [V] = 2 x L x C
R
x P
C
L - Cable length [m]
C - C
R
Specific resistance per meter [ Ω /m]
P - P
C
Power consumption [A]
Personnel:
n
Skilled electrician
1.
Install a power supply with adjustable output voltage to supply
the RMS supply input.
This is a requirement for voltage drop compensation.
2.
Calculate the actual voltage drop between RMS power supply
and RMS.
3.
Adjust the external RMS power supply to feed a slight
overvoltage of 5.1 V to 5.5 V depending on the measured drop.
– Select a conductor cross-section which guarantees a maximum
voltage drop of 0.2 V.
– Set the power supply to the upper limit of the RMS supply voltage.
A measurement system contains integrated electronic components.
Relating to the current consumption Power Automation only indicates
mean values. Current peaks of a multiple of the mean value may occur
for several microseconds during operation. These steps guarantee that
the RMS' supply voltage does not drop below the required minimum.
5.4 Installing digital I/O
The following chapters provide instructions and examples for
installation of digital inputs and outputs. Due to the versatility of the
control unit not all possible configuration options can be covered in
detail.
Calculation
Compensation
General
PA 8000 LW CNC control unit
Installation
25.09.2015 | 100