Siemens SIMATIC S7-200 - Installation Guidelines

S7-200 Specifications
A-47
S7-200 Programmable Controller System Manual
A5E00066097-02
Installation Guidelines
Use the following guidelines to ensure good accuracy and repeatability:
• Ensure that the 24-VDC Sensor Supply is free of noise and is stable.
• Use the shortest possible sensor wires.
• Use shielded twisted pair wiring for sensor wires.
• Terminate the shield at the Sensor location only.
• Short the inputs for any unused channels, as shown in Figure A-19.
• Avoid bending the wires into sharp angles.
• Use wireways for wire routing.
• Avoid placing signal wires parallel to high-energy wires. If the two wires must
meet, cross them at right angles.
• Ensure that the input signals are within the common mode voltage specification
by isolating the input signals or referencing them to the external 24V common
of the analog module.
Note
The EM 231 and EM 235 expansion modules are not recommended for use with
thermocouples.