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Ultima MOS-5 Detector
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
Table 6: Data Format
8.3 Modbus Read Status Protocol (Query/Response)
8.3.1 Modbus Read Query Message
Byte
Modbus
Range
Referenced to Ultima MOS-5
Intelligent Sensor
1
st
Slave Address
1-247* (Decimal)
Ultima MOS-5 Intelligent Sensor ID
(Address)
2
nd
Function Code
03
Read Holding Registers
3
rd
Starting Address Hi**
00
Not Used by Ultima MOS-5
Intelligent Sensor
4
th
Starting Address Lo**
00-FF (Hex)
Ultima MOS-5 Intelligent Sensor
Commands
5
th
No. Of Registers Hi
00
Not Used by Ultima MOS-5
Intelligent Sensor
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).