KROHNE MFC 010 C Converter - Manual (Page 27)

MFC010 Interface Manual 25
6.3 03 (03
16
): Read Holding Registers
This f unction per mits t he us er t o r ead t he v alue of a number of consecutive Holding registers. (See
Section 7.5 on page 49 for details of the individual registers). The format of the Master request telegram
for this function should be as follows.
Request
Character
Field For Example
1 Slave Address 01
16
Request to Slave ID 1
2 Function 03
16
“Read Holding Registers”
3 Start Address Hi 03
16
Start Address = 1023
4 Start Address Lo FE
16
5 No of Points Hi 00
16
No. of Points = 3
( Input Registers 1023 – 1025 ) 6 No of Point Lo 03
16
7 CRC Lo 64
16
CRC Checksum
8 CRC Hi 7F
16
The MFC010 will respond to such a request with a telegram formatted as follows.
Response
Character
Field For Example
1 Slave Address 01
16
Response from Slave ID 1
2 Function 03
16
“Read Holding Registers”
3 Data Bytes in Response 06
16
6 bytes ( 3 x 2 Byte Registers )
4 Data Byte 1 3F
16
Register 1023 = 16201
5 Data Byte 2 49
16
6 Data Byte 3 02
16
Register 1024 = 724
7 Data Byte 4 D4
16
8 Data Byte 5 F1
16
Register 1025 = 61730
9 Data Byte 6 22
16
10 CRC Lo 7D
16
CRC Checksum
11 CRC Hi BD
16