FCS meaning in oil and gas

Frame Check Sequence (FCS) Calculation Explained <p> <p> NTCIP and AB 3418 protocol developers typically use the inverse polynomial method to calculate the Frame Check Sequence (FCS). This method checks against the "magic number" of 0xf0b8 to ensure error-free transmission. ISO 3309 specifies the "magic number" of 0x1d0f, which is the reverse bits of 0xf0b8. The inverse polynomial method corrects for the fact that each byte's bits are reversed at transmission time when transmitted over serial lines, even though the method checks against a frame ordered most significant bit to least significant. <p> <p> FCS Calculation at the Transmitter<p> <p> The method to calculate an FCS at the transmitter is as follows: <p> <p> Invert the first 16 bits of the frame to be transmitted, 1's become 0's and 0's become 1's. <p> Add 16 zeros to the end of the frame. <p> Divide the frame by the generator polynomial. This step involves XORing the remainder repeatedly with the 17 bit generator polynomial until the remainder is 16 bits long. <p> The FCS is the 1's compliment of the remainder, R(x). <p>