Read Status (07); Force Multiple Coils (15) - Athena C10 Communications Manual

3.7 Read Status (07)

This function is used for reading the status of eight predetermined bits
with a compacted message. Broadcast mode is not allowed.
Question
The message consists only of the slave address and the function code
(07).
Example: Request of the status of slave 25.
ADDR FUNC
19
Answer
In addition to the address of the slave and the function code (07), the
message comprises a character containing the status bits.
Example: Answer to the request indicated above.
ADDR FUNC
19

3.8 Force Multiple Coils (15)

This function is used for forcing the status of each binary variable in a
consecutive block. Broadcast mode is allowed.
Question
In addition to the address of the slave and the function code (15), the
message contains the starting address expressed in two bytes, the
number of bits to be written, the number of bytes containing the data and
the data characters. The data are compacted, so one byte contains the
status of 8 bits, the least significant bit of the first byte must contain the
bit corresponding to the starting address and so on. If the number of bits
to be written is not a multiple of 8, the last character must be completed
with zeros in the most significant bits. Address numbering starts from
zero (bit1 = 0) for MODBUS, from one (bit1 = 1) for JBUS.
Example: Request to force 4 bits starting from address 1 on slave 12. Bits
1 and 4 forced to "1" and the others to "0".
ADDR FUNC
0C 0F
Answer
In addition to the address of the slave and the function code (15), the
message contains the starting address and the number of bits written.
Example: Answer to request indicated above.
ADDR FUNC
0C
CRC CRC
HI LO
07 4B E2
DATA CRC CRC
status
byte HI
07 6D 63
DATA DATA DATA
start start bit #
Addr HI Addr LO HI
00 00 00
DATA DATA DATA
start start
Addr HI Addr LO
0F 00 00
LO
DA
DATA DATA DATA
bit # Byte bit
LO Count 1..4
04 01 09
DATA CRC
bit # bit #
HI LO HI
00 04 55
CRC CRC
HI LO
3F 09
CRC
LO
15
13