Continuous 3-Point Analog Output; Function; Backup Mode; Ao Backup Value - Siemens TX-I/O User Manual

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4.12

Continuous 3-Point Analog Output

AO_Y250T_2Cha_1_Open (SIMATIC Manager hardware catalog)
AO_Y250T_2Cha_2_Close (SIMATIC Manager hardware catalog)
Continous 3-point analog output with two channels for positioning drives.
This function is used for the open/close control of three-position drives without
feedback (without a position potentiometer) – for example, for
 valve drives
 Damper actuators
 Third-party drives

4.12.1 Function

The function uses two channels. These must
 be in the same module and
follow in direct succession.

An internal stroke model (path algorithm) [StrkPos] calculates the required length of
the open or close pulses from the drive cycle time and the position defined by the
process value. No feedback is required by the drive.
The function supports asymmetric drives with different opening and closing cycle
times under the condition that this is also supported by the automation station.
AO_Cont3Point_Simple
SIMATIC HW catalog
AO_Y250T_2Cha_1_Open
AO_Y250T_2Cha_2_Close
The function converts the process value [AOValue] to a 3-position signal. A stroke
model [StrkPos](path algorithm) continuously simulates the position of the drive
based on the incoming control commands, and calculates the required length of
the open and close pulses from the drive cycle time and the position defined by the
process value. It therefore represents the drive position at all times. As a result, the
drive does not require corresponding feedback signals.
For full integration of all of the functionality – including the resulting stroke position
[StrkPos] and the function status [FncSta] – the 'Cluster Object Model' must be
applied (as described in PD622-F-0012 – Architectural Concepts).

4.12.2 Backup Mode

Function for control of the behavior of the function when changing to the
'MasterDown' status.
Possible values Description
NO Process value = INACTIVE, 0 (Off)
VALUE Specific value of the parameter [BOBackupValue]
KEEP Save the last active process value

4.12.3 AO Backup Value

TX-I/O PROFINET BIM V1.0
Parameters
Description
'Open' channel for the AO_Cont3Point_Simple function
'Close' channel for the AO_Cont3Point_Simple function
CM110564en_02
23.09.2010