Slave: Uninitialized Network

BF ST
Master LED Condition Light OFF Red Light Blinking
Absent Slave LED Condition

Uninitialized network

Light OFF Light OFF

** Process Flowchart**

* See also:

Symbol See also:
1 Disconnected Terminating Resistors, Cable Disconnection, Disconnected Connector, and Disconnected Signal Wire
2 Loose Connector and Signal Wire

Causes of Error

Possible Cause Examination Method Countermeasure
Electrical surges of device power supply Measure voltage of the device power supply at the trouble unit.

It should be within the range of sufficient voltage for device operation.

Check voltage of the device power supply.
  • Disconnected terminating resistors
  • Cable disconnection
  • Disconnected connector
  • Disconnected signal wire
  1. Check that terminating resistors are connected to both ends of the network.
  2. Measure resistance between signal wires with device power supply OFF.

    → Normal: 100 to 120 Ω

Fix the problem.

How to find the trouble point:

Remove the terminating resistor on one end of the network.

The trouble point is where resistance changes from 220 Ω.

  • Loose connector
  • Loose signal wire
Check for the connection of connectors and signal wires.

→ The connectors and signal wires should be firmly connected.

Connect the connectors and signal wires again.
Broken unit Replace the trouble unit with a new one.

→ Verify whether the problem is fixed.

Replace the unit with a new one.