• If the bus cable between the slave station 05(8) and 06(8) is disconnected in the following system.

03(8)

02(8)

01(8)

04(8)

Master

05(8)

06(8)

07(8)

station

 

 

 

 

B A

C

D

 

 

 

 

 

 

Disconnection

 

State of an individual communication flag

 

 

 

D7 6

5

4 3 2

1 D0

 

 

 

 

OFF

 

Unstable

OFF

 

 

 

 

Remove the connector on point A, and turn ON the termination resistance of the master station.

As the communication possible stations 03(8), 02(8), 01(8), and 04(8) are normal, the state of communication monitoring flag is as follows.

D7 6 5 4 3 2 1 D0

OFF ON OFF

Connect the A connector, and then remove the connector on point B.

8

Remove the connector on point C and make sure the B connector is not connected.

There is no normal station amoung commiunicatable station 05, 06, 07(8), and 05(8) is unstable.

D7 6 5 4 3

2 1 D0

OFF Unstable

OFF

As the communication possible station 05(8) is normal, abnormal points exists ahead of the point C.

D7 6 5

4 3 2 1 D0

OFF ON

OFF

Connect the C connector and make sure the B connector is not connected, and remove the connector at the next point to the point D.

The station 05(8) and 06(8) become communication possible stations, but the station 05(8) is unstable and the station

06(8) is turned to OFF, so the abnormal states occur between the point C and the point D.

D7 6 5 4 3 2 1 D0

OFF Unstable OFF

Cause

Countermeasure

Disconnection in the bus cable and the

Remove both the bus cable and

branch cable between the station 05(8) and

the branch cable connectors. After

06(8), or contact failure of the connectors

that, shorten one of these

 

connectors and check conductivity

 

using a tester.

 

 

Error on the slave station 06(8)

Exchange the slave module.

 

 

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