Siemens TX-I/O TXM1.8D Functions And Operation page 33

Note!
STOP
Response to failure
Failure
Address
key
Remote override
Display
Siemens
Building Technologies
Of course this only works if AC 24 V on the bus (conductor "
same transformer that supplies the source of the DC 24 V supply.
When backup value " Keep" is parameterized, the module is supposed to take no
activity at all, neither with absence nor with presence of bus or AC 24 V. Therefore, it
doesn't matter if bus terminal "V " (field device supply) is open or powered if there is a
bus connection module.
Modules of Series C actually work without AC 24 V connected.
With modules from Series D, however, it is compulsory to feed AC 24 V to bus terminal
"V " (field device supply) if there is a bus connection module. TXM1.6RL The module
always monitors this supply.
Simatic: It is also admissible to connect DC 24 V to bus conductor "V ".
As a summary, the I/O points behave as follows:
Bus AC 24 V
X
X
X
X X
Module type TXM1.6RL does not have a local override device, but remote override is
available for all I/O points.
• The I/O status LED is ON when the contact is closed.
• In the event of an error, the I/O status LED and the module status LED flash.
For details, especially in relation to flashing patterns and errors: refer to the section "Dis-
play, operation and diagnostics" in the TX-I/O™ Engineering and installation guide [6].
TX-I/O™ Module system – Functions and operation
Digital output functions

Behavior of relays
Off Backup
state
Masterdown
X
X
V
") comes from the very
Backup Backup
delay state
Powerdown
X
X
X
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