2.0, the analog and digital on-board I/O support the value status as
diagnostics option. You activate the use of the value status in the hardware configuration of
STEP 7 (TIA Portal). Value status is deactivated by default. You can activate/deactivate the
value status of the digital on-board I/O for X11 and X12 independently of each other.
When you activate the value status, the input area of the digital on-board I/O (X11/X12)
contains four additional bytes, which provide the QI bits to the 16 digital input channels and
16 digital output channels. You access the QI bits through the user program.
Value status of input channels
Value status = 1 ("Good") indicates that the value of the assigned input at the terminal is
valid.
Value status = 0 ("Bad") indicates that no/or too little supply voltage L+ is applied at the
terminal and that the read value is therefore not valid.
Value status of output channels
The value status = 1 ("Good") indicates that the process value specified by the user program
is correctly output at the terminal.
The value status = 0 ("Bad") indicates that the process value output at the hardware output is
incorrect or the channel is used for technology functions.
Possible cause for value status = 0:
● The supply voltage L+ is missing at the terminals or is not sufficient
● Outputs are inactive (for example, CPU in STOP)
● Technology functions (HSC, PWM or PTO) use the channel
Note
Behavior of the value status at the output channels for technology functions
The output channels return the value status 0 ("Bad") when a technology channel (HSC,
PWM or PTO) is used. It does not matter in this context whether the output value is incorrect
or not.Size of the input and output addresses of the high-speed counters
Inputs Outputs
Size per high-speed counter (6x) 16 bytes 12 bytes
You can find a description of the control interface in the section Assignment of the control
interface of the high-speed counters (Page 47). You can find a description of the feedback
interface in the section Assignment of the feedback interface of the high-speed counters
(Page 50).
Table 5- 2 Size of the input and output addresses in operating mode "Position input for Motion Control"The analog on-board I/O is set to voltage measurement type and measuring range ±10 V by
default for the inputs on channels 0 to 3. By default, channel 4 is set to resistance measuring
type and measuring range 600 Ω. If you want to use another measurement type or
measuring range, change the parameter settings of the analog on-board I/O with STEP 7
(TIA Portal).
Disable unused inputs to prevent disturbances that cause incorrect behavior (e.g. triggering