PROGRAMMING GUIDE
SINUS PENTA
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Data
The data field contains any additional information for the function being used.
Error Control
The error control is performed through the CRC (Cyclical Redundancy Check) method. The16–bit value of the relevant
field is computed when the message is sent by the transmitter and is then re–computed and checked by the receiver.
CRC Register is computed as follows:
1. CRC Register is set to FFFFh
2. Exclusive OR is executed between CRC register and the first 8 bits of the message; the result is saved to a 16–bit
register.
3. This register is right–shifted of one place.
4. If the right bit is 1, exclusive OR is executed between the 16–bit register and value 1010000000000001b.
5. Steps 3 and 4 are repeated until 8 shifts are performed.
6. Exclusive OR is performed between the 16–bit register and the next 8 bits of the message.
7. Steps 3 to 6 are repeated until all message bytes are processed.
8. The result is a CRC, that is attached to the message by sending the least significant byte as the first byte.
Supported Functions
03h: Read Holding Register
Allows reading the register state of the slave device. This function does not allow the broadcast mode (address 0).
Additional parameters are the address of the basic digital register to be read and the output number to be read.
06h: Write Single Register
Sets the state of one register for the slave device. In broadcast mode (address 0), the state of that register is set for all
the connected slave devices. Additional parameters are the register address and the relevant value.
10h: Preset Multiple Register
Sets the state of consecutive multiple registers (max 123) for the slave device. In broadcast mode (address 0), the state
of those registers is set in all the connected slave devices. Additional parameters are the basic register address, the
number of registers to be set, the relevant value and the number of bytes used for the data items.
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