RIEVTECH STUDIO SOFTWARE MANUAL In the Rievtech Studio software, the corresponding byte or word addresssymbolsare given according to the various connected devices. For the Rievtech FL2N series PLC,D represents the data register,SD represents the special address, represents the timer, C_word represents the 16-bits counter which saves the current value, and C_dword represents the 32-bits counter which saves the current value. As shown as below. 483