Part 1 specification – IAI America REXT User Manual
Page 153
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Part 1 Specification
Chapter 3 Gateway R unit
129
Part 1 Specification
z
Response
Field name
RTU mode data
(8 bits)
Data length (bytes)
Remarks
Header
None
-
Slave address
3F H
1
Fixed.
Function code
03 H
1
Data bytes
04 H
1
1-word register x 2 = 4 bytes
Data 1
(upper)
Arbitrary
Data 1
(lower)
Arbitrary
1 each for upper and
lower words
2
Data 2
(upper)
Arbitrary
Data 2
(lower)
Arbitrary
Same as above
Data of gateway status signal 0, 1
Error check
(CRC)
Based on
calculation result
2
Trailer
None
-
Total bytes
Arbitrary
z
Actual Example
Sent Query:
3F03F7000002F2A1
Received Response: 3F0304802100031C3B
Gateway status signal 0 is “8021H,” while status signal 1 is “0003H.” In other words, the RUN, W8B1, W4B1, LNK1
and LNK0 signals are ON.
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