34
Request from Master to Slave
Range
Byte
Slave address
1Dh
Function code
03h
Word starting address (high byte)
00h
Word starting address (low byte)
B2h
Number of words (high byte)
00h
Number of words (low byte)
03h
Error check (CRC-16) (low byte)
A7h
Error check (CRC-16) (high byte)
B0h
The 6 bytes in “Data” field (FFh, 9Ch, 80h, 00h, 05h, 5Ah) are 3 words whose meaning is:
word 178 value = -100 (FF9Ch)
word 179 value = not implemented or not relevant (8000h)
word 180 value = 1370 (55Ah)
12.6 Notes
1. “Broadcast” Address
When using the writing codes (5, 6, 15 and 16) the slave address 0 is permitted: in this case all
the slaves connected accept the command but do not give any reply.
2. Words Format
Every time the information transfer is performed by using 2 bytes (1 word of 16 bits), the first
byte transmitted is the most significant one. For the negative numbers the “two complement”
format is used.
3. Reply Time
The slave will start to send a reply from 2 ms to 700 ms after the end of the request detected by
counting the received bytes.
4. Decimal Digits
The decimal point that may be present in the value is ignored.
Example:
The value 204.6 is transmitted as 2046 (07FEh)
The value -12.50 is transmitted as -1250 (FB1Eh)
Every location that needs a decimal point has a related variable containing the number of
decimal digits; see also the “Attribute description” chapter.