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
• When detected, a new process value is carried out by the relay according to the I/O
function.
• The meaning of the I/O status LED can be parameterized:
Normal = green (default) / Alarm = Red / Service = Yellow.
• The way in which local override operates depends on the I/O function concerned
(one or multi-stage, maintained contact or pulse).
• Local override has first priority, followed by the various "functional tests" and (lastly)
operation via process value.
• Tool override of an I/O point is indicated by the flashing of the module status LED.
• With a change from automatic operation to local override, the process value (and
thus the status of the devices concerned) is retained until the user overrides it.
The same applies after the resumption of automatic operation, until the bus master
sends a new process value.
• For each I/O function local override can be disabled in the configuration.
For a full description see section 2.3, local override.
• Self-latching must be implemented externally to the I/O modules.
• The relay outputs associated with a function are mutually interlocked, which means
that these relays cannot be used independently of one another. It is therefore
recommended that contactors always be interlocked by external means (see the
connection diagrams in the data sheets).
• Feedback signals must be implemented separately, via a digital input.
• All safety-related functions must be implemented with external solutions
• The local override must not be used for safety switch-off
• In compliance with the standard (ISO 16 484-2, Section 3.110), the module
executes all local overrides directly, without safety precautions or interlocks.
Full responsibility for all operations lies with the operator.
Behavior in case of a fault
• Address key is swiveled out
• Failure of the module supply voltage DC 24 V (Powerdown)
• Failure of bus master (Masterdown, no datagram received for more than 4 s)
Local override
Engineering notes
Warning
Possible faults