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Model S4000T
29
8.0 MODBUS Interface
8.1 Baud
Rate
The Baud Rate is selectable via the Modbus Communications Interface. The
selectable baud rates are 19200, 9600, 4800, or 2400 bits per second.
8.2 Data
Format
The Data Format is selectable via the Modbus Communications Interface. The
selectable data formats are as follows:
Data Bits
Parity
Stop Bit
Format
8 None 1 8-N-1
8
Even
1
8-E-1
8 Odd 1 8-O-1
8
None
2
8-N-2
Figure 30 Data Format
8.3 Modbus
Read
Status
Protocol (Query/Response)
8.3.1 Modbus Read Query Message
Byte Modbus
Range
Referenced to S4000T
1
st
Slave Address
1-247* (Decimal)
S4000T ID (Address)
2
nd
Function Code
03
Read Holding Registers
3
rd
Starting Address Hi**
00
Not Used by S4000T
4
th
Starting Address Lo**
00-FF (Hex)
S4000T Commands
5
th
No. Of Registers Hi
00
Not Used by S4000T
6
th
No. Of Registers Lo
01
No. Of 16 Bit Registers
7
th
CRC Lo
00-FF (Hex)
CRC Lo Byte
8
th
CRC Hi
00-FF (Hex)
CRC Hi Byte
*NOTE -
Address 0 is reserved for broadcast mode and will not be supported at this
time.
** NOTE -
Start Address can be a maximum of 9999 Address Locations (0000-
270E).