Siemens TX-I/O TXM1.8D - Multistate Input Maintained Contact (MI Switch)

20/54
Siemens TX-I/O™ Module system – Functions and operation CM110561en_08
Building Technologies Digital input functions 2018-10-25
3.5 Multistate input maintained contact
(MI Switch)
• Mapping of several digital inputs to a single multistate value.
• 3 different mapping kinds are available:
– 1 to n mapping
– Up-down mapping
– Binary mapping
This feature covers the following signal type.
Signal type
Description
MI Switch Maintained contact, multistate, NO contact.
• This function uses one I/O point for each stage.
• The I/O points must be on the same module and adjacent to each other.
• 2...8 I/O points are admissible.
• The signal operation can be selected: Contact_NO (default), Contact_NC)
• Depending on the mapping kind, the I/O points can be active one by one or
simultaneously.
• The following mapping kinds can be parameterized (parameter Mapping Kind):
– 1 to n mapping
– Up-down mapping
– Binary mapping
• The multistate process value is mapped so that the mapping table defines just one
input to be active.
Before the process value MIValue changes, a time delay SwitchOverTime must
elapse, in order to debounce mechanical contacts (0...22.5 s, Default = 0.4 s).
• In the Mapping Table parameter, the default assignment of the I/O points to the
values of MIValue can be changed (for1 to n mapping only!).
• If more than one input is active, a Reliability Error message is transmitted (Quality =
MULTISTATE_FAULT) and the last valid process value stays active.
Active I/O point
MIValue
Stage
None
0
0
n
1
1
n + 1
2
2
n + 2
3
3
n + 3
4
4
:
:
:
n + 7
7
7
Active I/O point
MIValue
Stage
None
2
0 / Auto
n
1
1
n + 1
3
2
n + 2
4
3
Application
Signal types
Hardware
Function
1 to n mapping
Default mapping table
Example of a
modified table