How to Read Data Recorder Modules via Modbus in ION meters(ION8650/ION7650/ION750/ION8800)?

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Issue
How to Read Data Recorder Modules via Modbus in ION meters(ION8650/ION7650/ION750/ION8800)?

Product Line
ION8650, ION7650, ION7550, ION8800

Environment
3rd party software using Modbus

Resolution

Note: PM8000, ION7400 and ION9000 do not support reading Data Recorders through Modbus at this time. Some Modbus registers have been reserved for a possible future feature(FA381566).
There are other workarounds such as using Log Export Module to send email with log data attached as an xml file. Refer to ION Reference, Log Export Module for more details.

ION software tools such as ION Setup or Power Monitoring Expert (PME) use a proprietary protocol to communicate with ION meter. The proprietary protocol is the recommended method for accessing onboard logged data. Some ION meters include ION8650, ION7650, ION7550, and ION8800 can provide onboard logged data from Modbus registers.

In order to to retrieve Data Recorder Module's data via Modbus communication, follow the steps in "Appendix B: Data record / Modbus map" of document Modbus protocol and register map for ION devices:

Ensure the Data Recorder is online. See the ION Reference for Data Recorder module descriptions.
Write the Data Recorder module number to Modbus register 43001. If an invalid Data Recorder module number is written, a Modbus exception is returned.
Determine a valid Starting Record with a read of Modbus registers 43001 through 43011. This returns the Modbus Record Availability and Selection. All valid Record Numbers lie in the range of the Oldest Record Number (Modbus registers 43008 and 43009) and the Newest Record Number (Modbus registers 43010 and 43011).
After a valid Record Number is determined, write it to Modbus registers 43002 and 43003 (Client’s Request for Starting Record) so valid data is cached and read back.
A read of the Data Record Block returns the data for each available record starting at the record number written to Modbus registers 43002 and 43003. The number of records returned depends on the number of Source Inputs connected to the Data Recorder and the number of records available with respect to the Start Record.
Repeat steps 3 through 6 for new records.

Note:
Some Modbus tools apply offset 1 to the register(address or register number) that needs to be considered.

Example:
ION8650, Source 1 Input Data(kWh del) of Data Recorder 10 with Module label 'Egy&Dmd' is extracted by ModScan tool:

Data Recorder Module Egy&Dmd has number 10.
Write value 10 to register 43001.
Read Modbus registers 43001 through 43011 to find out a valid Starting Record of Newest Record Number (Modbus registers 43010 and 43011). Result is 11058.
Write value 11058 to registers 43003 and 43002.
Read the values starting registers 430018(Source 1 Input Data), 430020(Source 2 Input Data), etc. The results match the ION Setup values.