Modbus points 4-byte float swapped displays zero but Point locator test shows good values

[Pedro]

When using the "Point locator test" on the Modbus datasource configuration page, a good value is displayed after clicking on "Read." However, if that point is added as a regular point, 0 is displayed when mousing over the grey building block in the "Data points" list. Similarly, /point_details.shtm displays zero live and in the "Real-time history."

• "Discard extreme values" is not selected
• Register range is "Holding register"
• None of the "numeric" points are working, but binary points are working with the same datasource
• "Modbus read data" box shows non-zero hex values.
• The datasource log file displays outgoing and incoming Modbus packets, even when only one problematic point is selected.
• mango/logs/ma.log shows nothing
• There are no related datasource "Event alarm levels" generated.
• Disabling/enabling the source or the point does not fix the problem.
• core 2.7.2 build 465

Has anyone seen this problem before? What is the work-around? Were any changes made to the core or to the Modbus module that may fix this?

[craig]

do you have other holding register points on the data source? what if there is only the one?

Also try the "contiguous batches only" check box, some slaves will throw an exception if you you try to read a register that doesn't exist that may be between two blocks of defined registers.

[Pedro]

Craig, I noticed on the point_details.shtm page that it would display zero when the device was polled every five seconds, but when I clicked the green refresh icon, it would display the correct floating point value. After I checked the "contiguous batches only" check box, everything worked properly. Thanks for your help!