Why, after an application full download, some Modbus I/O scanning variables written to devices and driven by a BMENOC03x1 are not correct (bytes swapped) ?

Search FAQs

This problem is a known issue and fixed in firmware revisions :

- SV1.05 for BMENOC0321
- SV2.16 for BMENOC0301 and BMENOC0311

The issue occurs when all conditions below are met :

- when using firmware revisions lower than the ones described above
- when re-configuring and re-downloading application with a Modbus IO Scanner configuration into a BMENOC3xx (without doing a power cycle after the download)
- IO Scanner configuration contained a mix of "Read ONLY", "Write ONLY" and "Read/Write" modbus request
- some IO Scanner lines have been deleted and/or added

=> These four conditions may cause byte swapped data (for little endian conversion) on some modbus commands on the I/O scanning devices.

A global power cycle on the rack or hot swap of BMENOC03x1 makes the issue disappear.

We recommend to upgrade the BMENOC03x1 firmware to the latest available version.