Siemens SIMATIC SM 335 Manual page 34

Connecting the Inputs and Outputs of the SM 335
Cable
There is a voltage drop on the cable between SM 335 and the linear potentiometer.
Because of the SM 335's high resolution, this can play a role in the measuring of
the analog signal. You can compute the voltage drop on an electric cable as fol-
lows:
r · I · L
0
U +
A
Because of this, we would recommend keeping the cables as short as possible
and using a cable with the largest possible cross-section.
2-8
U: Voltage drop along the cable
r : Resistivity of the cable used
0
(for Cu: 0,0172 W mm
2
I: Current flowing through the cable in
amperes
L: Length of the cable in meters
A: Cross-section of the cable in mm
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
/m)
2
6ES7 335-7HG00-8BA1