Scaime eNod4-B - 7.5 eNod4 Profibus DP Features

39/95
User manual SCAIME: NU-soft-eNod4B-E-0716_236704-C.doc
- Transaction status is set to 0xFFFF in case of an error otherwise it takes the same value as the
one entered in the transaction request word.
- For a read transaction, the value of the requested setting is copied into the four IN following
bytes.
- For a write transaction the value of the data to be written is copied into the four IN following
bytes.
- For 16-bits size data, the data is read/written through the 16 last bits. Ignore the 16 upper bits.
 Note: the transaction request register must be set to 0x0000 before every new transaction.
7.4 Acyclic exchanges
For DPV1 class 1 and class 2 masters, another mechanism is available to write/read data into/from eNod4 device.
Acyclic exchanges are supported authorizing a class 1 master to send acyclic requests so as to read or write data into
memory area defined by a couple of slot/index.
A class 2 master can also send the same requests after initiating a connexion (up to 2) with eNod4. The
communication happens without disturbing the cyclic data exchange established between the device and the class 1
master.
 Note: be careful when using acyclic read/write requests. The 4-bytes size data are transmitted as 2x16 bits
blocks that need to be inverted so as to keep their consistency. For example 500 000
d
(0007A120
H
) is
read/written through acyclic requests as A1200007
H
.
7.5 eNod4 Profibus DP features
7.5.1 Sync
The Sync command can be transmitted from a master to one or more slaves. When receiving this command, eNod4
device is set into Synchro mode. Thus, the cyclic outputs of all the addressed slaves are maintained in their current
state. The cyclic outputs state is not updated until a new Sync command is received. The Synchro mode stops upon
reception of a Unsync command.
7.5.2 Freeze
The reception of a Freeze command causes eNod4 cyclic inputs to be frozen. Their state is not updated until a new
Freeze command is received. The Frezze mode stops upon reception of an Unfreeze command.
7.5.3 Fail-safe
eNod4 supports the Profibus DP Fail-safe mode. When the Profibus DP master asks eNod4 to switch to Fail-Safe
mode, eNod4 functioning changes according to following rules:
 eNod4 Profibus DP cyclic inputs goes on being refreshed
 eNod4 Profibus DP cyclic outputs are no more received
eNod4 remains as a “read-only device” until the master goes back to a normal working mode.
7.5.4 Profibus DP standard and extended diagnoses
eNod4 diagnosis frame is composed of a standard and a specific (called extended) parts that allow to inform the
Profibus DP master about the device functioning on the communication bus and about device internal errors. The
Profibus diagnosis frame has the following structure: