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VIPA System 300S
32bit access with Modbus
Master ASCII
6.4.4.1
FC 01 - Read Coil Status
HB130 | CP | 341-1CH01 | en | 18-40
1.
With Modbus Master ASCII the register oriented functions 03,06,16 may also
handle 32bit registers.
2.
Here the parameter "with 32-bit Register" is to be activated at "Modbus Master" of
the protocol properties.
3.
If activated there is the possibility to access 32bit registers by a "modified" function
code.
4.
By setting the 6. bit of the function code 32bit are accessed. If the 6. bit is not set,
16bit registers are accessed.
There are the following values for the function codes:
FC
03
06
16
–
Please regard the function code, which is sent is not affected by the
state of the 6. bit.
–
This serves for master information, which data size to be handled.
–
Please also regard to activate 32bit access in the slave, too.
This function serves to read individual bits of the output area of the slave.
DB SEND source
Address
Name
+0.0
ADDR
+1.0
FUNC
+2.0
start_addr
+4.0
bit_number
n
start_addr
–
start_addr is not checked by the driver and is sent unchanged.
n
bit_number
–
Any value between 1...2040 (ASCII: 1...2008) is permitted as bit_number.
DB RCV destination
Address
Name
+0.0
data[1]
+2.0
data[2]
...
...
Modbus > Modbus Master - Function codes
at 16bit access
03h
06h
10h
Type
BYTE
BYTE
WORD
INT
Type
WORD
WORD
...
Communication protocols
at 32bit access
43h
46h
50h
Comment
Slave address
Function code
Bit start address
Amount of bits
Comment
Data
Data
...
59
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