YASKAWA VIPA System MICRO Manual page 210

Option: PtP communication
Protocols and procedures
USS
Master slave telegram
STX LGE ADR
02h
Slave master telegram
STX LGE ADR
02h
210
The USS protocol (Universelle serielle Schnittstelle = universal serial interface) is a serial
transfer protocol defined by Siemens for the drive and system components. This allows to
build-up a serial bus connection between a superordinated master and several slave sys-
tems. The USS protocol enables a time cyclic telegram traffic by presetting a fix telegram
length.
The following features characterize the USS protocol:
n Multi point connection
n Master slave access procedure
n Single master system
Max. 32 participants
n
n Simple and secure telegram frame
It is essential:
n You may connect 1 master and max. 31 slaves at the bus
n The single slaves are addressed by the master via an address sign in the telegram.
The communication happens exclusively in half-duplex operation.
n
n After a send command, the acknowledgement telegram must be read by a call of the
FC/SFC 218 SER_RCV.
The telegrams for send and receive have the following structure:
PKE IND
H L H
PKE IND
H L H
with
STX - Start sign
STW - Control word
LGE - Telegram length
ZSW - State word
ADR - Address
HSW - Main set value
PKE - Parameter ID
HIW - Main effective value
IND - Index
BCC - Block Check Character
PWE - Parameter value
PWE
L H L
PWE
L H L
VIPA System MICRO
STW HSW
H L H
ZSW HIW
H L H
HB400 | CPU | M13-CCF0000 | en | 18-50
BCC
L
BCC
L