Operating Instructions

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Siemens TX-I/O™ Module system – Functions and operation CM110561en_08
Building Technologies Digital output functions 2018-10-25
5.8 Multistate pulse (MO Pulse / Q250-Px)
• For pulse control and pulse switching of multistate loads or the associated power
contactors with self-latching for each load step.
• Only one control output at a time is active.
• Examples:
– Fans
– Pumps
– Chillers
– Heat pumps
The following functions can be implemented by use of external circuits (and see the
connection diagrams in the module data sheet):
• If the control voltage for the self-latching circuit fails, the loads are not automatically
enabled when power is restored, even in the case of manual override. Example:
Power restoration circuit
• If the bus master fails, the loads are not disabled.
Example: lighting controls
• Local override on the module is possible; the contact interlock remains in effect.
• With a change from automatic operation to manual override, the power contactors
retain their last switch status.
• Two or more control circuits can switch the same load
(see connection diagrams in the data sheet).
Step switches, pulse switches, bistable relays: see Q250, section 5.2.
This feature covers the following signal type.
Signal type
Description
MO Pulse / Q250-Px
P-bus BIM:
– Q250-P3 only
– 1 to n mapping only
PROFINET BIM:
– Q250-P1...P4 only
Pulse, multistate with or without mutually exclusive
electronic relay interlock, depending on mapping kind
• The function uses one I/O point for each switched stage plus one I/O point for
switch-off.
• The I/O points must be on the same module and adjacent to each other.
• I/O point number (n) is always used for the switch-off command
• I/O point number (n+1) is used for the switch-on command for Stage (1), etc.
• Before a stage other than 0 is operated, relay n is switched for a period equivalent to
MinOffTime, interrupting the self-latching function.
MinOffTime can be parameterized: 0.1...25.5 s (default = 0.5 s)
(P-bus BIM: MinOffTime = 1 cycle period)
• The relay for the required stage is then operated for a period equivalent to PulseTime
• PulseTime can be parameterized: 0.1...25.5 s (default = 0.5 s)
(P-bus BIM: 0.5...25 s)
• The relays are latched.
• The signal type supports 1 to n mapping only.
Application
Note
Signal types
Hardware
Function