Multistate Maintained Contact (Mo Steps / Q-Mx) - Siemens TX-I/O TXM1.8D Functions And Operation

Application
Signal types
Hardware
Function
1 to n mapping
Siemens
Building Technologies
5.7 Multistate maintained contact
(MO Steps / Q-Mx)
• For control and switching of multispeed motors and other electrical loads or their
power contactors
• Can be used to switch one or more control outputs. Examples:
– Fans
– Pumps
– Chillers
– Heat pumps
– Electric heating coils
– Burners
This feature covers the following signal type.
Signal type
MO Steps / Q-Mx
P-bus BIM:
– Q-M3 only
– 1 to n mapping only
This function uses one I/O point for each stage to be switched.
The I/O points must be on the same module and adjacent to each other.
• I/O point No. (n) is used for the switch-ON command of Stage (1).
• depending on the mapping kind, the I/O points are latched or can be activated
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
output to be driven.
Despite the interlocking of the contacts inside the module, overlapping "ON" states
can occur (due to delayed release of the contactors, or "sticky" contacts) when
switching from one stage to another. For this reason the contactors must always be
interlocked externally (refer also to the connection diagram in the module data sheet)
• Any previously operated output is switched off before the next output is switched on.
The break time is 100 ms.
• In the Mapping Table parameter, the default assignment of the I/O points to the
values of MOValue can be changed (for1 to n mapping only!).
• If no value corresponding to the process value is found in the mapping table, a
Reliability Error message is transmitted (Quality = MULTISTATE_FAULT) and a
configurable back-up value is enabled (parameter Backup Value).
MOValue
0
1
2
3
4
5
6
TX-I/O™ Module system – Functions and operation
Digital output functions
Description
Maintained contact, multistate, relays with or without
mutually exclusive electronic interlock, depending on
mapping kind.
Active I/O point
Stage
0 None
1 n
2 n + 1
3 n + 2
4 n + 3
5 n + 4
6 n + 5
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CM110561en_08
2018-10-25