
7800 SERIESS7800A2142 4-Line LCD Keyboard Display Module
32-00110-07
52
The maximum number of addresses that can be queried is 127 (0x7F) for each query
message.
Table 9 through 12 provide information on the function codes.
NOTE: All Query and Response cells below are 1 byte.
Slave
Address
Function
Code
Starting
Address
High
Starting
Address
Low
Number
of Ad-
dresses
High
Number
of Ad-
dresses
Low
CRC
CRC
01
03 or
04
00
0A
00
01
A4
08
Table 9. Query Message Format for Function Codes 3 and 4.
Slave
Address
Function
Code
Byte Count Data High
Data Low
CRC
CRC
01
03 or
04
02
00
22
38
5D
Table 10. Response Message Format for Function Codes 3 and 4.
Slave
Address
Function
Code
Starting
Address
High
Starting
Address
Low
Preset
Data
High
Preset
Data Low
CRC
CRC
01
06
00
7F
00
04
B9
D1
Table 11. Query Message Format for Function Code 6.
Slave
Address
Function
Code
Starting
Address
High
Starting
Address
Low
Preset
DataHigh
Preset
Data Low
CRC
CRC
01
06
00
7F
00
04
B9
D1
Table 12. Response Message Format for Function Code 6
(There is no response if the query was broadcast.)
Slave Address
Function Code
CRC
CRC
03
11
C1
4C
Table 13. Query Message Format for Function Code 17.
Slave Address
Function Code
+ 80h
Exception Code
CRC
CRC
Table 14. Exception Response Message Format.
Exception Code
Definition
Description
01
Illegal Function
An illegal function as requested. Only 3, 4, 6 and 17 are
supported.
02
Illegal Data Ad-
dress
Too many bytes requested, address is out of range, reg-
ister is read only, or the number of address requested is
past the last register.
03
Illegal Data Value
The “Preset Data” from function code 6 is invalid/out of
range.
Table 15. Exception Codes.