Diagnosis

PROFIBUS state

In many cases it is important to know whether the communication with the higher-level master is still OK. To this end, link the "DpState" variable with your PLC program.

Diagnosis 1:
PROFIBUS diagnostic byte in the System Manager

Error number

Description

Remedy

0

No error

-

129

Waiting for configuration data

Start PROFIBUS

130

Waiting for parameter data

Start PROFIBUS

131

No master available

Check PROFIBUS cables and connectors

Sample

If the PROFIBUS is interrupted, e.g. if the cable is pulled or the PLC is switched, the Bus Terminal Controller indicates this by reporting 130 in DP state. That is, the Bus Terminal Controller is waiting for parameter data from the master.
Slave boot sequence after a timeout or starting of the master:
parameter data - configuration data - data exchange

Reading fieldbus state by ADS

In default or TwinCAT configuration the fieldbus state can be read via ADSREAD.

Parameter ADSREAD function block

Description

NetID

local – empty string

Port

1

IndexGroup

16#0006

IndexOffset

BX3100: 16#000C_A0F4 
BC3150: 16#000C_A080

LEN

1

State of the K-Bus

An internal bus or Bus Terminal error is indicated in the K-Bus state. A more precise fault description can be obtained via a function block (in preparation). To this end, link the "K-Bus state" variable with your PLC program.

Diagnosis 2:
K-bus status

Error bit

Description

Error type

0

No error

No ERROR.

Bit 0

K-Bus error

ERROR

Bit 2

K-Bus is re-triggered

NOTICE

Reading K-Bus state by ADS

In default or TwinCAT configuration the fieldbus state can be read via ADSREAD.

Parameter ADSREAD function block

Description

NetID

local – empty string

Port

1

IndexGroup

16#0006

IndexOffset

16#000C_9000

LEN

1