User manual for - FLOW METER SPP-N118
Let meter measures with precision 0,1 m
3
/h, parameters of
“Flouu”
menu should be
set as below:
“I tyPE“
=
“4-20mA”
- current input type
“I CHAr“
=
“Sqroot”
- input characteristic – square-root. It is necessary to obtain flow
rate readings direct proportional to pressure difference (using
differential pressure sensor proposed in example).
“Point”
=
“0.0”
- decimal point position, it allows to obtain displaying precision
0,1 m
3
/h
“F unit”
=
“m 3”
- parameters defining the unit flow as m
3
/h
“Ftunit”
=
“hour”
“Lo CAL”
=
“000.0”
- value displayed when input current is equal 4mA - 0,0 m
3
/h
“Hi CAL”
=
“010.0”
- value displayed when input current is equal 20mA - 10,0 m
3
/h
Parameter
“FiLtEr”
and
“CutoFF”
should be set if necessary. If it is necessary to input
current lower than 1% (it means 4.16mA) stop total flow counter incrementation then
“CutoFF”
parameter should be set to value
“1.0”
.
If user would like to protect input signal from the noise (to stabilize measurements), then
parameter
“FiLtEr”
should be set to value allowing easy readings.
10.
THE MODBUS PRO
TOCOL HANDLING
Transmission parameters: 1 start bit, 8 data bits, 1 or 2 stop bit (2 bits are send, 1 and 2 bits
are accepted when receive), no parity control
Baud rate:
selectable from: 1200 to 115200 bits/second
Transmission protocol:
MODBUS RTU compatible
The device parameters and display value are available via RS-485 interface, as HOLDING-
type registers (numeric values are given in U2 code) of Modbus RTU protocol. The registers
(or groups of the registers) can be read by 03h function, and wrote by 06h (single registers) or
10h (group of the registers) accordingly to Modbus RTU specification. Maximum group size for
03h and 10h functions can not exceeds 16 registers (for single frame).
The device interprets the broadcast messages, but then do not sends the answers.
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