User Manual

Logical I/O blocks
General functions
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The I/O objects have a monitoring function. The output objects monitor the
feedback signal from the plant. For this purpose, an address string must be
entered for the [FbAddr] feedback parameter [FbAddr] and the alarm function
must be enabled.
The input and value objects can monitor reference values. For this purpose, the
relevant reference values must be configured and the alarm function must be
enabled.
If the feedback value deviates from the output value [PrVal], a deviation alarm
is generated after a configurable time period, and the block status changes to
In Alarm . When the two values match again, and the configured time period has
expired, the alarm and status are reset. There is otherwise no automatic block
reaction, that is, if a switch response in the plant is required as a reaction to
this alarm, this response must be programmed in CFC via the Disturbance
output [Dstb].
It is also possible to configure the time period during which the maximum
deviation of the feedback signal may occur after a switch-on/off operation. If
the deviation persists after the monitoring time has expired, an alarm is
generated and the status of the block changes to
In alarm . When the two values
match again, and the configured time period has expired, the alarm and status
are reset. There is otherwise no automatic block reaction, that is, if a switch
response in the plant is required as a reaction to this alarm, this response must
be programmed in CFC via the Disturbance output [Dstb].
If no feedback monitoring is required, and the address string is left blank, the
monitoring periods are used by the block for the internal generation of the
transient state [TraSta]. This means that the transient state signal for the
switch-on/off operation is set for the preset period of time. This is how a
moving actuator, e.g., a damper, is displayed in the system.
Limit monitoring
Blocks: AI, AO, AVAL
In the case of the analog I/O blocks, the present value [PrVal] can be
monitored for a high/low limit. If the alarm monitoring feature is enabled, a
deviation alarm is generated after a configurable time period, and the block
status changes to
In Alarm . When the present value is within the limits again
and the configured time period has expired, the alarm and status are reset.
There is otherwise no automatic block reaction, that is, if a switch response in
the plant is required as a reaction to this alarm, this response must be
programmed in Xworks Plus (XWP) via the disturbance output [Dstb].
Deviation monitoring
Switch-on/off feedback
monitoring
No feedback monitoring