User Manual

Logical I/O blocks
Reliability table
19
CM110664en_07 273 | 351
The input value can be connected via the data flow. In the engineering tool, this is preceded by a function
block or compound, e.g., a Scheduler. However, if the input value is not connected, it can also be modified
via BACnet client. The subsystem registers a change in the input value by comparing the value with the
process image and transferring it to the field devices.
Trigger value
This input value is the logical image, or memory map, of an analog positioning command and describes its
properties. Within the program, the Present Value is made available to the block as a program value. The
block transfers the program value to the subsystem, from where it is transmitted to the field device.
Writing to this value acts as a trigger. This makes it possible, e.g., to generate the output of the same value
(e.g., Lighting 100%, followed later by 100% again). In this case the subsystem registers the trigger value
and transmits the value to the devices. This capability is required when the same variable can be modified
from several sources (e.g., when Desigo CC writes 100.0%, the local operator unit writes 0.0% and the
Desigo CC user wants to rewrite the value of 100.0%). The sources can be BACnet clients or system
function blocks.
Only analog trigger values may be used.
Commandable value
The input value is the logical image, or memory map, of an analog positioning command and describes its
properties. Within the program, the Present Value is made available to the block as a program value. The
block transfers the program value to the subsystem, from where it is transmitted to the field device.
The commandable value is based on the BACnet priority-mechanism (which is the same as for the output
blocks – refer to Section 0). A commandable value can be operated from various sources. Each source has
its own priority. The sources are mutually exclusive (interlock). The source with the highest priority
prevails, e.g., Emergency = Priority 1, Façade control = Priority 6, Operator = Priority = 8). The sources can
be BACnet operator units or system function blocks (grouping function).
Only analog commandable values can be used.
19.8 Reliability table
Value (decimal) Text
0 No error recognized.
1 No sensor.
2 Above the range.
3 Below the range.
4 Continuous loop.
5 Short circuit.
6 No output.
7 Unreliable other.
8 Process error
9 Multistate fault.
64 Subsystem not supported.
65 Subsystem feedback not supported.
66 Invalid address (syntax error).
67 Invalid feedback address (syntax error).
68 Invalid address value.
69 Invalid feedback address value.
70 Invalid address parameter (syntax error).
71 Invalid feedback address parameter (syntax error).
72 Invalid address parameter value.
Unsupported signal types in the automation station also generate reliability error message 72.
73 Invalid parameter value for feedback address.