ProSoft Technology ILX69-PBM - Manual (Page 116)

Contents ILX69-PBM ♦ CompactLogix or MicroLogix Platform
User Manual PROFIBUS Master Communication Module
Page 116 of 124 ProSoft Technology, Inc.
February 4, 2015
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.
Watchdog
Using the Watchdog functionality, a network slave is able to monitor bus traffic. This ensures
that the ILX69-PBM is still active, with process data still being updated. The Watchdog time
is configured in ProSoft fdt Configuration Manager and is transmitted from the ILX69-PBM to
the slave during the network start-up phase. If the Watchdog timeout has been reached, the
slaves go to their Fail Safe state (if supported) or set their outputs to "0".
9.1.2 DPV1 Services
As an addition to cyclic DPV0 services, acyclic services called Read, Write and Alarm were
added to PROFIBUS. These services are referred to as DPV1. With DPV1, it is possible to
address individual slaves within the network. In addition, DPV1 services allow the transfer of
non-time critical data to slaves. DPV1 data exchange takes place after cyclic data exchange
in a PROFIBUS network cycle.
Read Request
With a Read Request message, the ILX69-PBM can read data addressed by slot and index
within the data range of a slave device. This may take several DPV0 cycles. If the ILX69-
PBM discovers a timeout, it aborts both DPV1 and DPV0 communication with the slave. The
communication to the slave must be re-established. The ILX69-PBM initiates the Read
Request service.
Write Request
With a Write Request message, the ILX69-PBM can write data to a slave, addressed by slot
and index. The timeout handling is identical to the Read Request. The ILX69-PBM initiates
the Write Request service.
Alarm Indication
DPV1 Alarm handling is an addition to the Device Diagnostics function in a PROFIBUS
message. Alarms are reported to the ILX69-PBM as device-specific diagnostics information.
The slave initiates an Alarm Indication. Other than Device Diagnostics messages, Alarms
must be acknowledged by the ILX69-PBM.