User manual - METER SRT-94
10.3.
EXAMPLES OF QUERY/ANSWER FRAMES
Examples apply for device with address 1. All values are represent hexadecimal.
Field description:
ADDR
Device address on modbus network
FUNC
Function code
REG H,L
Starting address (address of first register to read/write, Hi and Lo byte)
COUNT H,L
No. of registers to read/write (Hi and Lo byte)
BYTE C
Data byte count in answer frame
DATA H,L
Data byte (Hi and Lo byte)
CRC L,H
CRC
error check (Hi and Lo byte)
1. Read of the displayed value (measurement), SRT-94 device address = 01h:
ADDR
FUNC
REG H,L
COUNT H,L
CRC L,H
01
03
00
01
00
01
D5
CA
a) The answer (we assume that the measure result is not out of range):
ADDR
FUNC
BYTE C
DATA H,L
CRC L,H
01
03
02
00
FF
F8
04
DATA H, L - displayed value = 255, no decimal point.
Decimal point position can be read from reg. 03h.
b) The answer (if an error occur):
ADDR FUNC
ERROR
CRC L,H
01
83
60
41
18
ERROR - error code = 60h, bottom border of the measurement range is exceeded
2. Read of device ID code
ADDR
FUNC
REG H,L
COUNT H,L
CRC L,H
01
03
00
21
00
01
D4
00
The answer:
ADDR
FUNC
BYTE C
DATA H,L
CRC L,H
01
03
02
DATA - identification code (20B0h)
41
Summary of Contents for SRT-94
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