Cable Separation And Routing - GE Mark VIe System Manual

6.6 Cable Separation and Routing

This section provides recommended cabling practices to reduce electrical noise. These practices include signal/power level
separation and cable routing guidelines.
Note Electrical noise from cabling of various voltage levels can interfere with microprocessor-based control systems,
causing a malfunction. If a situation at the installation site is not covered in this document, or if these guidelines cannot be
met, please contact GE before installing the cable.
Early planning enables the customer's representatives to design adequate separation of embedded conduit. On new
installations, sufficient space should be allowed to efficiently arrange mechanical and electrical equipment. On revamps, level
rules should be considered during the planning stages to help ensure correct application and a more trouble-free installation.
6.6.1 Signal and Power Level Definitions
Signal and power carrying cables are categorized into four defining levels; low, medium, high, and power. Each level can
include classes.
6.6.1.1 Low-level Signals (Level L)
Low-level signals are designated as level L. In general these consist of:
• Analog signals 0 through ±50 V dc, < 60 mA
• Digital (logic-level) signals less than 28 V dc
• 4 to 20 mA current loops
• Ac signals less than 24 V ac
The following are specific examples of level L signals used in the control cabling:
Note Signal input to analog and digital blocks or to programmable logic control (PLC)-related devices should be run as
shielded twisted-pair (for example, input from RTDs).
• All analog and digital signals including LVDTs, Servos, RTDs, Analog Inputs and Outputs, and Pyrometer signals
• Thermocouples are in a special category (Level LS) because they generate millivolt signals with very low current.
• Network communication bus signals: Ethernet, IONet, UDH, PDH, RS-232C, and RS-422
• Phone circuits
Installation Guidelines
Public Information
GEH-6721_Vol_I_BP System Guide 143