2920 Float & Tape Transmitter
MODBUSAppendix A — MODBUS Implementation
150
Installation and Operations Manual
Note
Exception: Because the 2920 FTT does not distinguish between inputs and outputs,
function codes 01 and 02 as they apply to bits, and function codes 03 and 04 as they apply
to numeric values refer to the same data registers. For example, either function code 03
or function 04 can be used to read the integer form of the level variable at data address 0.
Note
Default communications settings are shown in bold type above.
Functions and Data Formats
The MODBUS data in the 2920 FTT is arranged in integer registers, floating point registers, and
status bits. The assignments for these registers are found at the end of this appendix.
Function codes 03, 04, 06, and 16 are used with integer registers.
Because of the multiple MODBUS hosts available today, the 2920 FTT supports two floating-
point data formats: a two 16-bit register format and a one 32-bit register format. These two
Function
Code
Function
Information Type
MODBUS Nomenclature
01
Read
Bits
Read output status
02
Read
Bits
Read input status
03
Read
Integer, Coded, Status word,
Floating point
Read output registers
04
Read
Integer, Coded, Status word,
Floating point
Read input registers
05
Write
Bits
Force single output status
06
Write
Integer, Coded, Status word
Preset single register
15
Write
Bits
Force multiple outputs
16
Write
Integer, Coded, Status word,
Floating point
Preset multiple registers
65
Read
Floating point
Read floating point registers
66
Write
Floating point
Write floating point registers
Configuration Item
Valid Entries
(default in bold type)
MODBUS Config-
urable
ViewRTU
Configurable
MODBUS Address
1 to
254
No
Yes
Maximum Integer Size
Whole number (0 to 65,534)
(default:
9999
)
Yes
Yes
Integer Scaling Factors
Floating point number
Yes
Yes
Unit Selection
Coding list
No
No
Baud Rate
300, 600, 1200, 2400,
4800,
9600
, 19200
No
Yes
Parity
Odd, Even,
None
No
No
Summary of Contents for 2920
Page 2: ......
Page 16: ...2920 Float Tape Transmitter 1 Introduction 6 Installation and Operations Manual...
Page 114: ...2920 Float Tape Transmitter 6 Bi Phase Mark 104 Installation and Operations Manual...
Page 120: ...2920 Float Tape Transmitter 7 MODBUS 110 Installation and Operations Manual...
Page 126: ...2920 Float Tape Transmitter 9 L J TankWay 116 Installation and Operations Manual...
Page 158: ...2920 Float Tape Transmitter 14 Ordering Information 148 Installation and Operations Manual...
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