Siemens SINUMERIK 840D sl Function Manual page 38

A4: Digital and analog NC I/O for SINUMERIK 840D sl
2.2 Indirect I/O access via PLC
Setting mask
A PLC setting for each output can determine whether the current "NC value" (e.g. as specified
by the NC part program) or the "PLC value" specified via the setting mask should be output at
the hardware output.
The following sequence has to be carried out to define the "PLC value":
1. The relevant PLC interface output has to be set to the required signal status.
DB10 DBB6 or DBB132 ... (setting value of the digital NC outputs from the PLC)
2. The setting mask must be set to "1" for the relevant output:
DB10 DBB7 or DBB133 ... (setting mask of the digital NC outputs)
Unlike the overwrite mask, the NC value is not lost when a value is set in the setting mask. As
soon as the PLC sets "0" in the corresponding setting mask, the NC value becomes active
again.
Note
The same setting value is used at the PLC interface for the overwrite and setting masks.
Therefore, an identical output signal state is the result if the signal state is changed
simultaneously in the overwrite and setting masks.
Disable output
Digital NC outputs can be disabled individually from the PLC user program:
DB10 DBB4 or DBB130 ... (disable of the digital NC outputs)
In this case, the "0" signal is output at the hardware output.
Read setpoint
The current "NC value" of the digital outputs can be read from the PLC user program:
DB10, DBB64 or DBB186 ... (setpoint of the digital NC outputs)
Please note that this setpoint ignores disabling and the PLC setting mask. Therefore, the
setpoint can differ from the actual signal state at the hardware output.
Behavior at program end / reset
At the end of the program or on reset, a specific default value can be assigned by the PLC
user program to every digital output in accordance with requirements, using the overwrite
mask, setting mask or disable signal.
Response to POWER ON
After POWER ON, the digital outputs are set to "0" in a defined manner. This can be overwritten
from the PLC user program according to the specific application using the overwrite or setting
mask.
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Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Extended Functions