Communications Options User’s Guide
5
Chapter 1. Modbus Communications
Table 2: MODBUS Registers for a 1-Channel Gas Flowmeter
MODBUS Reg #
Description
Scaling
(decimal places)
Size in Bytes
1
1
”Clear Ch1 Totalizers”
--
2 (16 bit signed int)
2
Not Used
--
2 (16 bit signed int)
3, 4**
Velocity
2
4 (32 bit Long Integer)
5, 6*
2
Act Volumetric
--
4 (IEEE 32 bit Float)
7, 8*
2
Std Volumetric
--
4 (IEEE 32 bit Float)
9, 10**
3
Fwd Totals
Register 13
4 (32 bit Long Integer)
11, 12**
3
Rev Totals
Register 13
4 (32 bit Long Integer)
13
#Tot Digits
0
2
14, 15*
2
Mass Flow
--
4 (IEEE 32 bit Float)
16, 17**
4
Fwd Mass Totals
Register 20
4 (32 bit Long Integer)
18, 19**
4
Rev Mass Totals
Register 20
4 (32 bit Long Integer)
20
#MT DIGITS (Mass Tot Digits)
0
2
21, 22**
Timer
2
4 (32 bit Long Integer)
23
9
Error Code
0
2
24, 25**
Sound Speed
3
4 (32 bit Long Integer)
26, 27**
10
Density
4
4 (32 bit Long Integer)
28, 29**
Signal Strength Upstream
1
4 (32 bit Long Integer)
30, 31**
Signal Strength Downstream
1
4 (32 bit Long Integer)
32, 33**
Temperature
2
4 (32 bit Long Integer)
34, 35**
Pressure
3
4 (32 bit Long Integer)
92, 93 (36, 37)*
Signal Quality Up
--
4 (IEEE 32 bit Float)
94, 95 (38, 39)*
Signal Quality Down
--
4 (IEEE 32 bit Float)
96, 97 (40, 41)*
Amp Discriminator Up
--
4 (IEEE 32 bit Float)
98, 99 (42, 43)*
Amp Discriminator Down
--
4 (IEEE 32 bit Float)
100, 101 (44, 45)*
SNR Up
--
4 (IEEE 32 bit Float)
102, 103 (46, 47)*
SNR Down
--
4 (IEEE 32 bit Float)
508
6
MODBUS baud rate
0
2
509
7
MODBUS parity
0
2
510
8
MODBUS stop bits
0
2
511
MODBUS meter addr
0
2
