4 Function description
4.2 Modbus interface
Extension stage
Components
Functions
000142
Basic + flow direction det
temperature compensation
o
2 flowmeters
o
2 pick up each
o
1 temperature sensor Pt100
each
o
1 BEM 500 electronic unit
o
Electronic evaluation
o
Differential measurement
o
Flow direction detection
o
Mass flow measurement
o
Temperature compensation
o
2 relay outputs
o
2 analog outputs
o
2 pulse outputs
Tab. 6: Extension stages differential measurement
4.2 Modbus interface
Menu item
Variable
designation
Data
address
(HEX)
No. of
words
Raw data
(decimal)
Decimal
places
Explanation
of data
value
Data
reading
command
to BEM
(HEX)
1.01
QA rate
4006
2
+/-2 147 483 647
1 ... 3
Unit rate
0103 4006 0002 31CA
1.02
Total A1
4100
2
+/-2 000 000 000
1 ... 3
Unit total
0103 4100 0002 D037
Total A2
4102
2
+/-2 000 000 000
1 ... 3
Unit total
0103 4102 0002 71F7
1.04
Serial number
4012
2
0...999 999
0
–
0103 4012 0002 71CE
Software
4020
1
0...65 535
3
–
0103 4020 0001 9000
Hardware
410A
1
0...65 535
3
–
0103 410A 0001 B034
Tab. 7: Modbus variables
Data value
Value Meaning
Value Meaning
Value
Meaning
Unit rate
1
l/sec
9
lb/sec
17
galUK/h
2
l/min
10
lb/min
18
m
³
/min
3
l/h
11
lb/h
19
m
³
/h
4
kg/sec
12
galUS/sec
20
g/sec
5
kg/min
13
galUS/min
21
g/min
6
kg/h
14
galUS/h
22
ml/sec
7
t/min
15
galUK/sec
23
ml/min
8
t/h
16
galUK/min
Unit total
1
l
4
lb
7
m
³
2
kg
5
galUS
8
g
3
t
6
galUK
9
ml
No. of decimal
places
1
1 decimal place, this means all values with 1 ... 3 decimal places must be
divided by 10 (10
1
) to get the actual value.
2
2 decimal places, this means all values with 1 ... 3 decimal places must be
divided by 100 (10
2
) to get the actual value.
3
3 decimal places, this means all values with 1 ... 3 decimal places must be
divided by 1000 (10
3
) to get the actual value.
Tab. 8: Data values
Example for Total TA1
Data reading command to BEM (query):
0103 4100 0002 D037
Response from BEM:
0103 0400 0160 9E02 5B
Value
Meaning
01
03 0400 0160 9E...
01
= Modbus device address 1
01
03
0400 0160 9E...
03
= Read holding registers function
Operating instructions
OIE 15en-GB Edition 2020-03
11
