Since some Modbus analog values can reside in two consecutive register pairs, it is possible to read these values in one read message. For example, registers 146 and 147 could contain one 32 bit value (0xF025A476). The read message should always be directed to the first register address of the register pair.
(I40) Reading the registers as one 32 bit signed decimal value:
>25R146I40:CC <25D:-265968522:CC(I41) Reading the registers as one 32 bit unsigned decimal value:
>25R146I41:CC <25D:4028998774:CC(I42) Reading the registers as one 32 bit hexadecimal value:
>25R146I42:CC <25D:F025A476:CCThe SPA implementation cannot check that the two Modbus registers actually belong together as one value. Any two independent consecutive 16 bit registers can be read freely in one 32 bit data value packet.