Data Exchange
2-3
Slave Data Set
General Information
The data associated with each slave is organized as follows:
Slave Status Register
This register reflects the current status of the slave.
• RES (Reserved)
Reserved for future use, mask off and ignore.
• FNF (Fieldbus Network Fault)
This bit indicates if the fieldbus has gone on- (set) or off- (cleared) line.
• USSF (USS Fault)
This bit is set if a USS master-slave communication fault has been detected.
• OP (Operational)
This bit is set if the gateway has detected the slave and found it operational.
• CFG (Configured)
This bit is set (1) if the node is configured in the master or cleared (0) if not configured.
• Slave No.
USS slave address (0... 31).
Process Data (PZD)
This is the actual Process Data (PZD) image.
Parameter Data (PKW)
The gateway does not process the Parameter Data (PKW) data in any way. This means that the param-
eter access protocol used to access PKW data, if required, must be implemented entirely on the PLC
side. Exactly how this is done is beyond the scope of this document.
Data from Gateway
Data from IO Controller
Slave Status Register
(reserved, set to zero)
(2 bytes)
Parameter Data (PKW)
Parameter Data (PKW)
(size is device dependent)
Process Data (PZD)
Process Data (PZD)
- “ -
(lsb)
(lsb)
b15
b14
b13
b12
b11
b10
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
RES
FNF USSF OP
RES CFG
RES
Slave No.
