Fema Electronica K Series, User Manual, Page: 11 / 32

FEMA ELECTRÓNICA . Series K . K40-232
11
1.18 Registers in ‘Text’ mode
Register
number
Name Type
(R=Read, W=Write)
Description
0 Display R / W
Register with the alphanumerical characters to represent on display. See
section 1.21 for a list of representable characters.
1 Reserved --- ---
2 Reserved --- ---
3 Reserved --- ---
4 Reserved ---
5 Reserved ---
6 Alarm status R / W Status of alarms 1, 2 and 3 (see section 1.20).
Table 5 - Registers in ‘Text’ mode
• if the register contains more than 6 characters, the ‘scroll’
mode is activated
(see section 1.28.3).
• the alarm status is accessible at register 6. The format of this
register is explained at section
1.20
.
• after power loss, the instrument will start-up with all registers
initialized to a value of ‘0’
(see section 1.8).
List of registers accessible
(see Table 5)
for an instrument configured
in ‘Text’ mode.
• register 0 contains the value to show on display. It is an alpha -
numerical value. The register can contain up to 71 characters.
• acceptable characters are indicated at
Table 7
.
• character ‘+’ is represented as an empty space.
• characters received not included in this table, are shown as
3 horizontal stripes on display ( ).
1.19 CRC calculation
The frame_value for the CRC byte is calculated based on the frame_
values (see section 1.14) of the bytes from the ‘Header’ and ‘Data’
sections. Calculation consists on a ‘XOR’ function from byte ‘0’ (‘STX’)
to the last data byte (byte Dn).
• If the CRC calculated value is lower than ‘32’, it is normalized with
the function ‘complement to 1’.
CRC0=STX ^ ID ^ RSV ^ FROM ^ TO ^ REG ^ RSV ^ LONG ^ D0 ^...^ Dn
• Si (CRC0<32) -> CRC=!CRC0 (complement_to_1 function)
• Si (CRC0>31) -> CRC=CRC0
//example of CRC calculation in C language
int8 Calculate_CRC(int8 CRC_Position)
{
int8 i,CRC=0;
for(i=0;c<CRC_Position;c++)
{
crc=crc ^ frame[i];
}
if(crc<32) CRC=~CRC;
return(CRC);
}