Trouble Detection And Solution - Hitachi LQE550 User Manual

6 MAINTENANCE

6.2.2 Trouble detection and solution

Is the terminating resistor properly set?
• Be sure to short a terminating-resistor setup terminal (see "2.1 Names and Functions of
Each Part") to a module positioned at the end of a line. If terminating resistor setup is not
completed, a communication error occurs successively or intermittently.
• Check that the employed terminating-resistor setup terminal matches the cable's
characteristic impedance.
CPU link module
Terminating
resistor
Are the wiring connections properly made?
• Check that the link cable extension length is as
specified (see "1.2 Specifications").
• If different types of cables are used for the same
CPU link line, a communication error may occur.
When making wiring connections for a line, use
only one type of cable.
• Check cables for disconnection or incorrect
connection.
CPU link module
6-6
Terminating
resistor
CPU link module