Epson RC620 Manual page 201

♦ Process Flowchart
Check for cable laying.
Check that
terminating resistors
are connected.
Normal
Turn OFF all units.
Measure resistance
with tester.
100 to 120 Ω
Normal
See 4.2.3.2.
RC620 Option Fieldbus I/O Rev.8
Problem exists.
(Add terminating resistors.)
Out of 100 to 120 Ω (Error)
Resistance: over 120 Ω
Yes
Remove one terminating
resistor on either side.
Approx. Measure
Ω
220 resistance at
connectors
with tester.
Other
Find the trouble point.
(1) Unconnected or loose connector
(2) Cable disconnection, etc.
4. Troubleshooting (PROFIBUS DP)
No
Resistance: under 100 Ω
10 to 100 Ω
Check for connection of
terminating resistors.
(1) Three or more
terminating resistors
(2) Wrong terminating
resistors, etc.
Under 10 Ω
Check for short
circuit between
signal wires.
Short circuit
between signal
wires
191