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65
Generic Slave Device DTM
Section 2-5
Max. Alarm PDU Length
This parameter defines the maximum size of an Alarm message sent from the
slave device to the PROFIBUS DP-V1 Master Unit. The Master Unit uses this
number to reserve buffers to handle the alarms. The maximum alarm mes-
sage size ranges from 4 bytes to 63 bytes
Alarms
The Alarms box defines the types of alarms the slave device will report, as
well as the alarm handling capacity of the master device. The settings in this
box are conveyed to the slave device through the Set_Prm message sent by
the PROFIBUS DP-V1 Master Unit.
Extra Alarm SAP
For acyclic data exchange between a PROFIBUS DP-V1 Master Unit (Class
1) and a PROFIBUS DP-V1 slave device one specific SAP (Service Access
Point, the PROFIBUS definition for a message identifier) is defined by the
PROFIBUS DP Extension standard. By default SAP 51 is used for acyclic
data exchange with the PROFIBUS DP-V1 Master Unit (Class 1).
For efficiency reasons however, acknowledgement of alarms, can be per-
formed using a different, dedicated SAP or message identifier, SAP50. This
will allow other acyclic communication (e.g. re-parameterization of the slave
device) to continue without interference.
Control
Description
Alarm mode
The Alarm mode indicates to the slave device the amount
of alarms the PROFIBUS DP-V1 Master Unit can process
simultaneously. The following standard selections are
available:
• 1 alarm of each selected type
• 2 alarms in total
• 4 alarms in total
• 8 alarms in total
• 12 alarms in total
• 16 alarms in total
• 24 alarms in total
• 32 alarms in total
Pull Plug alarm
When set, this checkbox enables the signalling of a pull/
plug alarm type, i.e. the removal/insertion of a hardware
I/O module.
Process alarm
When set, this checkbox enables the signalling of a pro-
cess alarm type, i.e. an alarm related to the process con-
nected to the I/O.
Example: Upper Limit exceeded alarm.
Diagnostic alarm
When set, this checkbox enables the signalling of a diag-
nostic alarm, i.e. an alarm related to the functioning of a
specific I/O module in a slot.
Example: Short circuit detected.
Manufacturer specific
alarm
When set, this checkbox enables the signalling of a Manu-
facturer specific alarm.
Status alarm
When set, this checkbox enables the signalling of a Status
alarm, i.e. an alarm related to an internal state change in a
module.
Example: Change to Run state, Stop state.
Update alarm
When set, this checkbox enables the signalling of an
Update alarm, i.e. an alarm indicating a change in the
parameters related to a specific module, either by local or
remote access.