The ION 75xx RTU reads -1 for all external numeric registers and will not save any changes after a register write

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Issue
User is getting -1 when reading an externa numeric register. The user may notice that any changes to this register will not save

Product Line
ION 7550 and ION7500 RTU

Environment
ION Framework

Cause
The ION 75xx RTU units do not come with predefined framework on the meters. If a module does not exist on the framework, modbus requests will return -1.

Resolution
Use ION Setup or ION Designer to create external numeric modules and unlock the registers. Once the module has been created the register will read 0 instead of -1.