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Siemens
TX-I/O™ Module system – Functions and operation
CM110561en_08
Building Technologies
Digital output functions
2018-10-25
Of course this only works if AC 24 V on the bus (conductor "
V
") comes from the very
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:
Failure
Behavior of relays
Address
key
Bus
AC 24 V
Off
Backup
state
Masterdown
Backup
delay
Backup
state
Powerdown
X
X
X
X
X
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].
STOP
Note!
Response to failure
Remote override
Display