MYERS Illuminator Supernova Series, Installation Manual

Page: 66 / 131

65
115895B System Installation Manual
MODBUS SERIAL COMMUNICATION OPTION SECTION
o
0x0001 is the File Number (for the Alarm Log File)
o
0x0000 is the Record Number (we
’re starting to read the file from
byte 0)
o
0x0020 (32) is the Record Length. We wish to read the first 32
bytes of the file.
Response PDU 1
14 42 41 06
00 31 00 39 00 2f 00 30 00 38 00 2f 00 32 00 31
00 09 00 30 00 39 00 3a 00 33 00 31 00 09 00 49
00 4e 00 56 00 45 00 52 00 54 00 45 00 52 00 20
00 46 00 41 00 55 00 4c 00 54 00 0D 00 0A 00 31
Where:
o
0x14 (20) is the Read File Record function code
o
0x42 (66) is the remaining length of the PDU in bytes
o
0x41 (65) is the file read response length (including the Reference
Type byte)
o
0x06 is the Reference Type (fixed)
o
The last 64 bytes of the PDU are byte pairs. If you eliminate all the
(0x00 valued) most significant bytes of each byte pair, you are left
with the ASCII data read out of the Alarm Log file:
31 39 2f 30 38 2f 32 31 09 30 39 3a 33 31 09 49
4e 56 45 52 54 45 52 20 46 41 55 4c 54 0D 0A 31
Note that 0x09 is the
‘tab’ character, and 0x0D 0x0A is a DOS style
line ending (
“\r\n”). The ASCII would display as:
19/08/21 09:31 INVERTER FAULT
1
Request PDU 2
14 07 06 00 01 00 20 00 17
Where:
o
0x14 (20) is the Read File Record function code
o
0x07 is the remaining length of the PDU in bytes
o
0x06 is the Reference Type (fixed)
o
0x0001 is the File Number (for the Alarm Log File)
o
0x0020 (32) is the Record Number (we
’re starting to read the file
from byte 32, where we left off)
o
0x0017 (23) is the Record Length. This is the remainder of the file
(55
– 32 = 23 bytes)
Response PDU 2
14 30 2F 06
00 39 00 2f 00 30 00 38 00 2f 00 32 00 35 00 09
00 32 00 32 00 3a 00 31 00 34 00 09 00 4c 00 4f
00 57 00 20 00 56 00 41 00 43 00 0D 00 0A
Where:
o
0x14 (20) is the Read File Record function code
o
0x30 (48) is the remaining length of the PDU in bytes