Page 30 • MNFL003 ║ Issue/Rev. 0.1 (9/13)
microFlow.net Liquid Modbus Communications Manual Appendix
The status of inputs 1031 through 1024 is shown as the byte value AC hex, or binary
1010 1100. Input 1031 is the MSB of this byte and input 1024 is the LSB. The status of
inputs 1031 through 1024 is expressed as ON-OFF-ON-OFF-ON-ON-OFF-OFF, from
left to right.
The status of inputs 1033 through 1032 are shown as the byte value 01 hex, or binary
0000 0001. Input 1033 is in the seventh bit position from the left and input 1032 is the
LSB. The status of inputs 1033 through 1032 is OFF-ON. The six remaining bits toward
the high order end are padded with zeros, since the returned input quantity must be a
multiple of eight.
4.9 03 Read Holding Registers
Description
Reads the binary contents of holding registers (read/write registers).
Query
The query message specifies the starting register and quantity of registers to be read.
Registers are addressed starting at zero.
An example of a request to read registers 107 through 109 from microFlow.net Liquid
17 is shown below:
Query
Field Name Example (Hex)
microFlow.net Liquid Address 0x11
Function 0x03
Starting Address Hi 0x00
Starting Address Lo 0x6B
No. of Points Hi 0x00
No. of Points Lo 0x03
Error Check (CRC) (calculated)
Response
Each register data in the response message contains two bytes. The binary contents
are right justified within each byte. Within each register, the first byte contains the high
order bits and the second byte contains the low order bits.
An example of a response to the preceding query is shown below:
Response
Field Name Example (Hex)
microFlow.net Liquid Address 11
Function 03
Byte Count 06
Data Hi (Register 107) 02
Data Lo (Register 107) 2B
Data Hi (Register 108) 00
Data Lo (Register 108) 00
Data Hi (Register 109) 00
Data Lo (Register 109) 64
Error Check (CRC) --
To Next Page
Loading...
