short RTU_readInRegs(u8 comCh, u8 slaveAdr, u8* result, u16 targetAdr, u8 numOfRegs)
comCh: The RS-232 channel to use |
slaveAdr: The Modbus slave address of the device to read from |
result: Buffer to store coil (bit) data to |
targetAdr: The address of the data to read |
numOfRegss: Number of registers (words) to read |
returns the status of this function call (-1=Success, 0=Timeout, 1=Data Error) |
Performs the same operation as RTU_readRegs but uses Modbus function code 4. The MOACON does not distinguish between function codes 3 and 4, but some PLCs do. This function is provided so the MOACON can interface properly with those PLCs that distinguish between function codes 3 and 4.
u8 registerBuffer[100]; res = RTU_readInRegs(0,1,registerBuffer,0,2);