Models FL3100/3101
30
8.4.2 MODBUS Write Response Message
Byte
MODBUS
Range
Referenced to FL3100, FL3101
1
st
Slave Address
1-247
*
(Decimal)
FL3100, FL3101 ID (Address)
2
nd
Function Code
06
Preset Single Register
3
rd
Register Address
Hi
**
00
Not used by FL3100, FL3101
4
th
Register Address
Lo
**
00-FF (Hex)
FL3100, FL3101 Commands
5
th
Preset Data Hi
00-FF (Hex)
FL3100, FL3101 Hi Byte
Command Data
6
th
Preset Data Lo
00-FF (Hex)
FL3100, FL3101 Lo Byte
Command Data
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 is not be supported at
this time.
NOTE
**
- Register Address can be a maximum of 9999 Address Locations
(0000-270E)
8.4.3 Function Codes Supported
Function Code 03 (Read Holding Registers) is used to read status from the slave
unit. Function Code 06 (Preset Single Register) is used to write a command to
the slave unit.
8.5 Exception Responses and Exception Codes
In a normal exchange, the master device sends a query to the FL3100, FL3101.
The FL3100, FL3101 receives the query and returns a normal response to the
master. If a normal communications error occurs, there are 4 possible responses
from the FL3100, FL3101:
1.
If the FL3100, FL3101 does not recognize the query due to a
communications error, then no response is returned from the FL3100,
FL3101 and the master device will eventually process a timeout condition for
the query.
2.
If the FL3100, FL3101 receives the query, but detects a communication error
(CRC, etc.), then no response is returned from the FL3100, FL3101 and the
master device will eventually process a timeout condition for the query.
3.
If the FL3100, FL3101 receives the query without a communications error,
but cannot process the response to the master within the master's timeout
setting, then no response is returned from the FL3100, FL3101 and the
master device will eventually process a timeout condition for the query.