Integer Format (32 Bits); Crc (Cyclic Redundancy Check) - Trumeter 898X Serie Manual De Instrucciones

Machine precision
The relative machine precision indicates the maximum relative error that can be generated during rounding
(conversion). For the Float values (single floating point), the machine precision is ε

5.8.2 Integer format (32 bits)

The Integer format is used in the representation as a two's complement. The device interprets the transmitted
integer value. If the data value is represented in the device with the set number of decimal places, the decimal
point is set for the integer in compliance with the set number of decimal places.
Example for a setting to 3 decimal places:
Transmitted integer value:
Interpreted value:

5.9 CRC (cyclic redundancy check)

A 16 bit CRC value is calculated according to a defined process for every data block and appended to the
data block. For data check purposes, the same calculation process is applied to the data block, including the
appended CRC value. If the result is zero, it can be assumed that the data block has not been corrupted.
CRC generation algorithm:
1. Loading of the value FFFF
2. Exclusive OR operation on the first byte sent or received with the low byte of the CRC register; store the
result in the CRC register
3. Shift the CRC register 1 bit to the right and fill the msb with 0
4. If a 0 has been shifted out in step 3, this step is repeated. If a 1 has been shifted out in step 3, an
exclusive OR operation is carried out on the CRC register with the value A001
5. Steps 3 and 4 are repeated until 8 bit shifts have been performed.
6. Steps 2 to 5 are repeated for the other bytes sent or received.
7. The result of the CRC generation is now in the CRC register. They are appended to the sent message
after a byte exchange.
msb: most significant bit
Page 8 | ENG
00000010
hex
000.016
dec
Address X + 1
00 00
hex hex
Byte 4 Byte 3
in the 16 bit CRC register
hex
Address X
00 10
hex hex
Byte 2 Byte 1
− 8
= 5,96 * 10 .
0
.
hex