Novatek-electro PEF-321ABP, Operating Manual

Page: 15 / 16

~ 15 ~
PEF-
321АВР
NOVATEK-ELECTRO
The subroutine for generating LRC checksum is in C language:
1: uint8_t GenerateLRC(uint8_t *p
СendRecvBuf, uint16_t uCount)
2: {
3: uint8_t lrc = 0x00;
4: uint16_t i;
5: for(i=0; i<(uCount-1); i++){
6: lrc = (lrc + p
СendRecvbuf[i]) & 0xFF;
7: }
8: lrc = ((lrc ^ 0xFF) + 2) & 0xFF;
9: returnlrc;
10: }
6.3.4 Set of instructions
6.3.4.1 Function 0x03 - read operation of a group of registers
The 0x03 function reads the contents of 321ABP registers. The master
‟s request contains the address of the
initial register, as well as the number of words to read.
Answerback of
321АВР contains the number of bytes returned and the requested data. The number of
registers returned is limited to 50. If the number of registers in the request exceeds 50, the response is not split
into frames.
An example of a request and response in the MODBUS RTU is shown in Figure 11.
Request
Address Function
In. address
HB
In. address
LB
Number of words
HB
Number of words
LB
CRC LB CTC HB
01h 03h 00h A0h 00h 02h C4h 29h
Answerback
Address Function
Number of
bytes
HW HB
data
HW LB
data
LW HB
data
LW LB
data
CRC LB CTC HB
01h 03h 04h 44h 7Ah 00h 00h CFh 1Ah
Fig. 11 - Example of request and response of function 0x03 - reading a group of registers
6.3.4.2 Function 0x06 - register entry
Func
tion 0x06 provides writing to one 321ABP register. The master‟s request contains the address of the
register and data for entering.
The answer of the device coincides with the request of the master unit and contains the address of the
register and the established data. An example of a request and answer in the MODBUS RTU mode is shown in
Figure 12.
Request
– register 00A0h = 1000 (INT)
Address Function
In. address
HB
In. address
LB
HB
data
LB
data
CRC LB CTC HB
01h 06h 00h A0h 03h E8h 89h 56h
Answerback
Address Function
In. address
HB
In. address
LB
HB
data
LB
data
CRC LB CTC HB
01h 06h 00h A0h 03h E8h 89h 56h
Fig. 12 - Example of request and answer of function 0x06 - register setting
7 MAINTENANCE
7.1
Safety precautions
THE TERMINALS AND THE DEVICE INTERNAL ELEMENTS CONTAINS POTENTIALLY LETHAL
VOLTAGE.
DURING MAINTENANCE IT IS NECESSARY TO DISABLE THE DEVICE AND CONNECTED
DEVICES FROM THE MAINS.
7.2 Maintenance of the device must be performed by the skilled professionals .
7.3 Recommended frequency of maintenance is every six months .
7.4 Maintenance Procedure :
1) Check the connection reliability of the wires, if necessary, clamp with the force specified in Table 1;
2) Visually check the integrity of the housing, in case of detection of cracks and damages take the device out
of service and send for repair;
3) If necessary, wipe the front panel and the housing of the device with cloth.
Do not use abrasives and solvents for cleaning.