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Siemens
TX-I/O™ Module system – Functions and operation
CM110561en_08
Building Technologies
Digital output functions
2018-10-25
5.3 Maintained contact, triac
(BO Triac NO / NC
)
On/off switching of AC 24 V devices,
especially:
– Frequent switching (triacs do not have any problems with contact life span)
However, check the admissible switching frequency of the connected
device and adjust the parameters or the application accordingly.
– Other devices with AC 24 control
– silent switching
•
The function is supported by module type TXM1.8T only.
•
The function requires one I/O point.
•
The supply is AC 25 V, the triay closes the contact to
⊥
(system ground).
•
Technical data (max. output of the triacs): see data sheet N8179.
Process value
I/O status LED
Relay
Active
Inactive
On
Off
10561D01
Active
Inactive
The signal operation can be selected: Triac (Default), Triac_NA
In the case of
bus failur
e, with DC 24 V module supply available, the following backup
states van be parameterized:
– No
(Inactive) (= default)
– Value (Active, Inactive)
– Keep Same value as before the bus failure
Parameterization can be done during runtime.
•
The
I/O status LED
is ON when the
triac
is active, i.e. when the N/O contact is
closed and the N/C contact is open.
•
In the event of an error, the
I/O status LED
and the
module status LED
flash.
For details, especially in relation to flashing pattern and errors: refer to the section "Dis-
play, operation and diagnostics" in the TX-I/O™ Engineering and installation guide [6].
TXM1.8T has no local override.
The quality value "No_Output" is sent when AC 24 V is absent.
In this case the triac can not be activated
the module switches the output off and
sets the process value to 0.
The fault message is only sent when a command is pending.
Application
Hardware
Function
Parameterization
Display
Local override
Fault message