Mitsubishi Electric Melservo MR-J3-A Instruction Manual page 396

14. ABSOLUTE POSITION DETECTION SYSTEM
(c) Checksum
The check sum is the code which is used by the programmable controller to check for errors in the
received ABS data. The 6-bit check sum is transmitted following the 32-bit ABS data.
At the programmable controller, calculate the sum of the received ABS data using the ladder program
and compare it with the check sum code sent from the servo.
The method of calculating the check sum is shown. Every time the programmable controller receives 2
bits of ABS data, it adds the data to obtain the sum of the received data. The check sum is 6-bit data.
Example: ABS data:
Therefore, the check sum of " 10" (ABS data) is "2D
10 (FFFFFFF6H)
b
10
<Appendix>
b
01
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
11
b
101101
Decimal
FFFF FFF6
Hexadecimal
1111 1111 1111
Binary
When the binary data of each 2bits of the
ABS data is added up, "10 1101 " is obtained.
b
"
14 - 11
10
0110
b