Convert a DWORD into Individual BOOL Signals in PCS 7 CFC

In PCS 7 CFC, use the DW_BO elementary block to split a DWORD into 32 Boolean signals: IN bit 0 maps to OUT0, bit 1 to OUT1, through bit 31 to OUT31. Siemens' CFC block help documents this mapping. For PCS 7 V8.1, confirm the block exists in the installed library, connect the source to IN, then use the corresponding outputs.

Use the DW_BO conversion block

Siemens CFC elementary-block help defines DW_BO with a DWORD input named IN and 32 BOOL outputs (OUT0 through OUT31). The mapping is positional: IN-Bit0 becomes OUT0, IN-Bit1 becomes OUT1, continuing through bit 31. This separates a packed bit field; it does not interpret the DWORD as a measurement.

Configure it in CFC

Confirm that the source is DWORD and determine each bit's meaning from the producing device or application specification.
In the installed PCS 7 V8.1 CFC library/help, locate DW_BO and confirm its interface.
Place it in the chart and connect the DWORD source to IN.
Connect required outputs to BOOL parameters while preserving bit numbering.
Compile and validate using the project's normal procedure.

Use WORD conversion for a 16-bit source

For a WORD, use W_BO, which provides 16 outputs, OUT0 through OUT15. Do not truncate a DWORD if bits 16–31 are significant. Siemens documents WORD and DWORD conversions separately.

Verification

In an approved test environment, use a known pattern or online values to confirm that bit 0 changes OUT0, bit 1 changes OUT1, and representative higher bits map to same-numbered outputs. Validate the source bit definitions separately; conversion does not assign semantic meaning.

Limitations and Operational Precautions

The available Siemens block-help document is newer than PCS 7 V8.1. Confirm block availability and interface in the installed V8.1 library. Avoid test patterns on a live control path if they could change outputs or interlocks.

Engineer FAQ

How many BOOL outputs come from a DWORD? 32, one per bit.

Does OUT0 represent the most significant bit? No. Siemens maps IN-Bit0 to OUT0 through IN-Bit31 to OUT31.

Can W_BO convert all 32 bits? No; it provides 16 outputs for a WORD.

Does conversion define bit meaning? No; consult the signal or protocol specification.

Technical References

Siemens, Help on CFC – Elementary Blocks, section 9.3 “DW_BO” and “W_BO,” defines DWORD/WORD to BOOL mapping. Confirm availability in the installed PCS 7 V8.1 library: https://support.industry.siemens.com/cs/attachments/109973511/s7jbib_b_en-US.pdf