7 DEVICE SUPPORT BLOCK (DSB)
Combination of any of the above, with
the same scope
After the diagnostic condition returns to normal for the channels whose status is "Bad," the affected channels change
their status to request the PIOMB to back initialize these channels. This is applicable only for the output channels.
In addition, the following two scenarios result in the output value initialization in the Siemens DP/AS-i Link
When the PDA connection is lost or closed, the output channel values are held or set to 0 (Off) and these
output values are written to the appropriate AS-i slave devices.
However, the output value written to the slave devices depends on the value of the HOLDONFAIL
When the PDA connection is restored with the controller, the output values are back-initialized to the
The Siemens DP/AS-i Link DSB does not support remote/local control of AS-i device input/output values. Therefore,
there are no initialization scenarios for these. In addition, there is no read-back of output values from the AS-i slave
devices. Therefore, the back initialization is performed using the values which are held internally in the DSB, typically
the last written value.
The Siemens DP/AS-i-Link DSB can have one AS-i slave error alarm for each configured slave in the system. It
can have up to 62 active slave error alarms.
The alarms conditions are processed at the same rate as the PROFIBUS data is cyclically fetched. However, the
alarms are reported at the DSB's cyclic execution period of one second.
The following table lists the various alarms reported by the Siemens DP/AS-i-Link DSB. This table also
provides information on the priority and severity of each alarm.
One of the diagnostic conditions listed in the table below must exist for at least one second to ensure that an alarm is
AS-i Slave Error
AS-Interface voltage low
DP/AS-I Link module is
Largest scope of common diagnostics
Only the Siemens DP/AS-i-Link DSB has the
Alarm indicates which AS-i slave device has
an error (1 – 31). Theoretically, if you had 31
slave devices and all of them had errors you
would see 31 alarms in Station.
This alarm only provides notification of AS-i
voltage low if either the DP/AS-i Link is on
an external 24V power source or there is still
enough power on the AS-i cable for the
DP/AS-i Link to operate.
This alarm provides the communication error
(when there is the failure of the whole
Unspecified hardware error with the DP/AS-i