Supplements to ET 200SP documentation
2.1 System Manual
Product information on the documentation of the ET 200SP distributed I/O system
34 Product Information, 02/2021, A5E03799595-BG
Section 7.4 Value status
Value status (QI, quality information) refers to status information of I/O channels that is made
available to the user program via the process image input (PII). However, since the value
status is partly derived from the diagnostics, there may be a time delay between the
occurrence of the error and the message depending on the diagnostics.
Each bit of the value status is assigned to a channel and provides information about the
validity of the process value of the respective channel (1 = no errors on the channel of the
I/O module, 0 = value is bad).
The assignment of the value status bytes in the process image input depends on the module
used. Detailed information can be found in the manual for the relevant I/O module.
Summary: Possible cause for value status = 0:
• A channel has an error (overflow/underflow, wire break, short-circuit, etc.)
• The supply voltage L+ is missing at the terminals or is not sufficient
• A channel has been deactivated
• PROFIenergy pause is activated
• Outputs are inactive (value status = 0: Module not plugged in. Value status is generated
via interface module in distributed mode)
If, for example, there is a wire break at an input but the wire break diagnostics is disabled, the
value status of the channel is set to "0" but no diagnostics is triggered. Diagnostics is only also
triggered if the wire break diagnostics is enabled.
With module-by-module channel diagnostics of the I/O modules, these also map the value
status module-by-module. The channels are mapped here module-by-module to value status
= 0 or value status = 1.
Which interface modules support the value status
The following interface modules support the value status:
• IM 155-6 PN ST
• IM 155-6 PN HS
• IM 155-6 PN/2 HF
• IM 155-6 PN/3 HF
• IM 155-6 MF HF
Which I/O modules support the value status
The I/O modules of the function classes Standard, High Feature and High Speed support the
value status.
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