Annex; Profibus Functionality; Dpv0 Services - ProSoft Technology ILX69-PBM User Manual

Annex

User Manual
9 Annex
9.1

PROFIBUS Functionality

9.1.1 DPV0 Services

PROFIBUS DPV0 services refer to the cyclic data exchange mechanism between a
class 1 master and a slave. PROFIBUS DP defines two types of masters:

A class 1 master handles data communication with slaves assigned to it

A class 2 master is used for commissioning purposes
In a PROFIBUS message, class 1 masters and slaves transmit up to 244 bytes. Valid
station addresses on a PROFIBUS network range from 0 to 126.
Fail Safe Mode
For safety reasons, the ILX69-PBM informs the slaves of its current control status at
certain intervals using a "Global Control" message. If the ILX69-PBM goes to Clear
Mode, the Fail Safe enabled slaves will switch to a Fail Safe state. Slaves capable of the
Fail Safe state can be configured to either to hold the last state of the outputs or set its
outputs to "0". Slaves that do not support the Fail Safe state set their outputs to "0".
Global Control
With the Global Control message, the ILX69-PBM can send unsolicited commands like
Sync/Unsync, Freeze/Unfreeze and Clear Data to a slave or a group of slaves for
synchronization purposes. Group membership is defined during network start-up and in
ProSoft fdt Configuration Manager.
Sync and Freeze
Sync and Freeze are optional commands where slaves do not need to support them.
The slaves must be able to process the Global Control message. With a Freeze
command, the ILX69-PBM prompts a slave or a group of slaves to "freeze" their inputs
to the current state. A Sync command causes the current output data to latch at their
current state until the next Sync message arrives. Unfreeze and Unsync cancel each
corresponding state.
Extended Device Diagnostics
Using diagnostics messages, the slave informs the ILX69-PBM of its current state in a
high-priority message. The first 6 bytes of the diagnostics message are comprised of
information such as its identity code ("Ident Number") and correct/incorrect configuration.
The remaining bytes of this message are referred to as Extended Device Diagnostics,
containing information that is specific to the particular slave.
Page 108 of 113
ILX69-PBM ♦ CompactLogix™ or MicroLogix™ Platform
PROFIBUS Master Communication Module
ProSoft Technology, Inc.