ProSoft Technology PS69-DPM - Manual (Page 68)

Contents PS69-DPM ♦ CompactLogix or MicroLogix Platform
User Manual PROFIBUS DPV1 Master
Page 68 of 130 ProSoft Technology, Inc.
October 1, 2014
Byte Offset Member Name Data Type Description
84 Seq_Nr SINT Sequence Number (0 to 31)
85 Alarm_Type SINT Alarm Type (1 to 6, 32 to 126)
86 Alarm_Spec SINT Alarm Specification (0 to 7)
87 Reserved SINT Reserved
Alarm_Status
Bit Offset Member Name Data Type Description
0 AlarmInd BOOL Alarm Indication
1 Reserved BOOL Reserved
2 Reserved BOOL Reserved
3 Reserved BOOL Reserved
4 Reserved BOOL Reserved
5 Reserved BOOL Reserved
6 Reserved BOOL Reserved
7 AlarmOverrun BOOL Alarm Overrun
The alarm indication registers start with the byte "Alarm_Status". This byte is a collection of
bits to indicate alarm status. Bit D0 (AlarmInd) is set to "1" to indicate to the user application
that an alarm request has been received by the module. The specifics of the alarm request
will be present in the remaining alarm indication fields, which contain the slave station
address "Rem_Add", the slot number "Slot_Number", and so on. according to the
PROFIBUS specification. If an alarm is indicated, the user application has to decide what to
do with its application specific reaction.
The application has to respond to the alarm with a CIP message, which is described later in
this manual. With its response, the application confirms to the slave that the alarm was
received. When the user application responds to the alarm using a CIP message Bit 0 will
be set to "0" indicating that the alarm has been acknowledged and is no longer pending. The
alarm information Rem_Adr, Slot_Number, and so on. is not cleared. It can happen that a
second or more alarms are pending. In this case bit D0 will not be reset to "0" when the
application has responded to one alarm. Only the alarm information Rem_Add,
Slot_Number and so on. will be update in the case of multiple alarms pending.
To handle this situation the application has to look also to the variable "AlarmCnt". This
counter will be incremented every time a new alarm is pending.
NOTE: It is possible to receive several alarms from one or more slaves. The master module has a buffer for only
32 alarms. The application has to respond as fast as possible to alarms. If the internal alarm buffer runs over,
further alarms are lost. This situation is indicated by the "Alarm_Status" bit D7 "AlarmOverrun". If an alarm was
loss, this bit is set to "1". It will be cleared only if the bus communication is stopped for example if the controller
goes to stop or the application stops the bus communication by the NRDY bit in the command register.