Operating Instructions

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Siemens TX-I/O™ Module system – Functions and operation CM110561en_08
Building Technologies Default functions, disabling function 2018-10-25
Testing options with default functions
Test
Action
I/O status LED
LCD display
Remark
Testing of inputs
TXM1.8D, 16D (BI Default)
Shorting the input
ON
TXM1.8U (-ML), TXM1.8X (-ML)
(UIO Default)
No voltage
(input open or shorted)
OFF
–75 ... +75 µA at input OFF
High-resistance
conductivity tester

Do not use!
>75 µA at input ON
Correct polarity of
low-resistance
conductivity tester
(buzzer)
< –75 µA at input Flashing 1 Hz Incorrect polarity of
low-resistance
conductivity tester
(buzzer)
>11.5 V at input Flashing 1 Hz
E.g. DC24 V connec-
ted by mistake
AC24 V at input Flashing 1 Hz
AC24 V connected by
mistake
TXM1.8P (RI Default)
< 40 Ohm at input
ON
(no LCD) Especially short circuit
> 40 Ohm at input OFF
(no LCD)
Testing of
TXM1.6R (-M), TXM1.6RL, TXM1.8T (BO Default)
digital outputs
Local override or tool
override enabled
ON / OFF
The module executes all local over-
rides or tool overrides directly, without
safety precautions or interlocks.
 Special care is required 
Testing of
TXM1.8RB
blinds modules
Tool override enabled
OFF / Stage 1 / Stage 2
Testing of
analog outputs
TXM1.8U (-ML),
TXM1.8X (-ML)
UIO Default is an input function. For safety reasons,
planned analog outputs can not be tested with
unconfigured modules.
As soon as the modules are configured, you can use the
functional tests of the building automation and control
system.