Chapter 1. Modbus Communications
20
Communications Options User’s Guide
Figure 1: Menu Map for Sentinel LCT or Sentinel LNG Flowmeter
Table 8: Data Type/Symbol for the Sentinel LCT or Sentinel LNG Flowmeter
Symbol
Numeric Type
Size Register Sequence
Comments*
1
2
3
4
I
Integer
1W
Single, signed 16-bit word
L
Long integer
2LSW
MSW
32-bit signed integer may be listed as double word
on some types of programmable logic controller
(PLC).
U
Unsigned long
integer
2LSW
MSW
32-bit signed unsigned integer may be listed as
double word on some types of programmable logic
controller (PLC).
F
Floating point
2LSW
MSW
Single-precision floating point number specified in
IEEE Standard for Binary Floating-Point Arithmetic
(ANSI/IEEE Std 754-1985), also known as
IEC60559:1989, Binary floating-point arithmetic for
microprocessor systems.
D
Double-precision
floating point
4LSW
W
W
MSW Double-precision IEEE 754 floating point number is
not supported by many PLCs.
B
Bit field
2LSW
MSW
32-bit field where each field represents a
particular status (i.e. 0=off/inactive and
1=on/active).
*For data stored in multiple 16-bit registers, the Least Significant Word is usually transmitted first. The sequence can
be inverted, i.e.: the Most Significant Word is sent first and the LSW last, by toggling a global meter setting. Within each
two-byte register, the most significant byte must always be sent first.
Address #
Modbus
RS485
RS232
4800
19200
9600
None
Even
Odd
CONFIG
Units
Units
Units
Units
Parity
