ABB OETL1600K3 Panel Accessories

In RTU mode, messages include an error-checking field that is basedon a Cyclical Redundancy Check (CRC) method. The CRC fieldchecks the contents of the entire message. It is applied regardless ofany parity check method used for the individual characters of the mes-sage.The CRC field is two bytes, containing a 16-bit binary value. The CRCvalue is calculated by the transmitting device, which appends the CRCto the message. 

The receiving device recalculates a CRC duringreceipt of the message, and compares the calculated value to theactual value it received in the CRC field. If the two values are not equal,an error results.The CRC is started by first pre-loading a 16-bit register to all 1's. Thena process begins of applying successive 8-bit bytes of the message tothe current contents of the register. Only the eight bits of data in eachcharacter are used for generating the CRC. Start and stop bits, and theparity bit if one is used, do not apply to the CRC.