with the Address (instrument number): 0 (20H) is shown as follows.
• 1’s complement: Make each bit of binary 0 and 1 reverse.
• 2’s complement: Add 1 to 1’s complement.
5.3 Command contents
Notice of setting and reading command
• Possible to set the setting value by setting command of the communication function
even
if
the
setting value is locked
• Even if the option is not applied, it is possible to set it by the setting command, however,
the contents of the command is ineffective.
• The setting value can be extended around 1,000,000 times before the memory expires.
If the number of setting times exceeds the limit, it cannot memorize data. So frequent
transmission via communication is not recommended.
• When connecting plural JC series, instrument numbers (address) must not be duplicated.
• When sending a command by Global address [95 (7FH)], the same command is sent to all the
slaves connected. However, the response is not returned to the Master.
• The instrument number and data transfer rate of the JC series cannot be set by communication.
Setting command
• The settable range is the same as the one in the case of key operation.
Refer to the communication command table of this manual as for communication command.
•
All commands are written in ASCII.
• The data (setting value) is converted from decimal to a hexadecimal number, and ASCII is used.
Negative numbers are represented by 2's complement. When the data (setting value) has
a decimal point, use the whole number as response omitting decimal point.
Reading command
• All commands are
written in
ASCII.
• The data (setting value) is converted from decimal to hexadecimal number, and ASCII is used.
Negative number is represented by 2's complement. When the data (setting value) has
a decimal point, it returns the whole number with the decimal point omitted.
6. Modbus protocol
6.1 Transmission mode
There are 2 transmission modes (ASCII mode and RTU mode) in Modbus protocol.
[ASCII mode]
Hexadecimal (0 to 9
，
A to F), which is divided to MSD (4-bit) and LSB (4-bit) out of 8-bit binary
data in command is transmitted as ASCII characters.
STX
ETX
P
0
0
0
1
0
2
5
8
02H
20H
20H
50H
30H
30H
30H
31H
30H
32H
35H
38H
03H
[Characters above are represented by ASCII]
Checksum
Checksum calculation range
[e.g.]
E
45H 30H
0
20H
20H
50H
30H
30H
30H
31H
30H
32H
35H
38H
0010 0000
0010 0000
0101 0000
0011 0000
0011 0000
0011 0000
0011 0001
0011 0000
0011 0010
0011 0101
0011 1000
+
10 0010 0000
[Hexadecimal]
[Binary]
1101 1111
1
+
1110 0000
E
0
45H
30H
[1's complement]
[2's complement]
[Hexadecimal]
[ASCII]
Checksum