Glossary
PROFIBUS manual
Version FELD-V2002.02
Page 35
PROFIBUS PA:
Process Automation. PROFIBUS definition for process
automation in accordance with IEC 1158-2 and DIN E 19245 Part
14. The protocol is very similar to PROFIBUS DP but has a
different physical bus design. Typically used in the chemicals
industry. Not supported by the DIGIFORCE
®
type 9310.
PDU:
Process Data Unit. The net data to be transferred is specified in
the PDU.
PI:
PROFIBUS International
Piggy back:
Electronic module that is plugged into another board to provide
specific functions. In this case it refers to a PROFIBUS interface.
PNO:
PROFIBUS user organization based in Karlsruhe, Germany. Non-
profit association representing the interests of PROFIBUS
suppliers.
Repeater:
Used for signal conditioning when linking together the individual
bus segments.
SAP:
Service Access Point providing unique identification of the data
to be transferred and requested within a message. Each message
contains a Source SAP and a Destination SAP (exception: data is
transferred via the default SAP)
PLC:
Programmable Logic Controller
State machine:
Describes how a PROFIBUS station is to respond in every
situation.
Sync mode:
This command is used to make a slave "hold" the outputs. This
mode is an optional service and is often used for synchronization
purposes. Not supported by the DIGIFORCE
®
type 9310.
TBit:
Unit of time e.g. for transferring a bit on the PROFIBUS
(reciprocal of the baud rate, e.g. 1 TBit at 12 Mbaud
Æ
1/12000000 bits/sec
Æ
83 ns).
Token:
The active station (master station) holding the token can exchange
data with the slaves (passive station) that it has parameterized and
configured. At the end of a data cycle, the active station passes
the token to the next active station.
Certification test: The PROFIBUS certification test is performed by experts
(PROFIBUS user organization) and tests for non-compliance of
the device. Plug and Play only works with certified units.