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sigfox MODBUS MASTER - Guide utilisateur / User guide version V1.0.1
68
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FR
4.2.4 Frame for updating the VALUE of specific registers
This frame (0x41) allows to change the VALUE of requested registers.
0
1
2
3
4
5
…
7
Code
PAYLOAD
0x41
CONF ID1
CONF ID1
VALUE
CONF ID2
CONF ID2
VALUE
CONF ID2
VALUE
…
CONF IDn
VALUE
Description of the frame :
• Byte 1: CONF ID1 (8bits) : indice of the first register to change. The corresponding register is 300 + value of CONF IDX. For example, if
CONF ID1 = 0x14 (hexadecimal, so 20 decimal), the product will change the value of register number 320.
• Byte 2: VALUE to assign to CONF ID1 : in this example, its VALUE has a size of 1 byte
• Byte 3: CONF ID2 (8bits) : index of the second register to change. The corresponding register is 300 + VALUE of CONF IDX.
• Bytes 4 and 5: VALUE to assign to CONF ID2 : in this example, its VALUE has a size of 2 bytes
• …
The product does not return any uplink frame following the reception of a downlink frame 0x41 et 0x43. However, the Config bit of the status
byte (see section 4.1.1.2) will be set to 1 in the next scheduled uplink frame (periodic or alarm or keep alive frame) if all was well done.
IMPORTANT: the VALUE 0xFF for a CONF IDX will stop the reading of the downlink frame. Only the bytes preceding this VALUE 0xFF will be
taken into account. This mechanism can be useful when you need to work in fixed downlink frame lengths and you do not want to use all
available bytes.