Siemens simatic et200sp User Manual

Wiring
3.3 Current transformer selection data
Analog input module AI Energy Meter 480VAC ST (6ES7134-6PA20-0BD0)
22 Manual, 12/2015, A5E36061895-AA
Maximum length of the connection cable
To avoid overloading or damaging the current transformer, the burden Z
n
specified on the
data sheet of the current transformer (in VA) must not be exceeded. To prevent this being
exceeded, the entire burden resistance (consisting of the resistance of the connection cable
and the internal resistance of the AI Energy Meter 480VAC ST (see figure below) must be
below a certain resistance value (depending on Z
n
and I
max
).
Image 3-2 Maximum length of the connection cable
The maximum value of the resistance of the connection cable is obtained with the following
formula:
R
L
Cable resistance in ohms I
max
Secondary current of the current trans-
former
Z
n
Rated burden current transformer in VA
R
burden
Resistance of the Energy Meter (25 mΩ)
Image 3-3 Maximum value for the resistance of the connection cable
Based on the maximum cable resistance in ohms, you then calculate the maximum length of
the connection cable. To do this, check the data sheet of the connection cable you are using.
Note
The length of the connection cable (outwards and return) must not exceed the value of
200
meters.

Siemens simatic et200sp Specifications

General

Category	I/O Systems
Power Supply	24 V DC
Protection Rating	IP20
Number of Modules	Up to 64 modules
Mounting	DIN Rail
Communication Protocols	PROFINET, PROFIBUS
Storage Temperature	-40 °C to +70 °C
Digital Inputs	Yes (depending on module)
Digital Outputs	Yes (depending on module)
Analog Inputs	Yes (depending on module)
Analog Outputs	Yes (depending on module)
Modularity	Modular
Relative Humidity	5 to 95% (non-condensing)
Weight	Varies by configuration
System Type	Distributed I/O