SiteLab SL1188P, Инструкция по эксплуатации

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SL1188P Ultrasonic transit-time flowmeter
Revision
：
2.0.0
Page
42
of
81
Menu
5 5
Current Loop Mode Select
CL Mode Select [55
0. 4 - 20 mA
Select the current loop mode. The following options are available:
0. 4-20mA set up the output range from 4-20mA
1. 0-20mA set up the output range from 0-20mA
2. 0-20mA via RS232 set up to be controlled by Serial Port
3. 4-20mA VS.Fluid set up the CL output 4-20mA corresponding sound velocity
4. 20-4-20mA set up the CL output range from 20-4-20mA
5. 0-4-20mA set up the CL output range from 0-4-20mA
6. 20-0-20mA set up the CL output range from 20-0-20mA
7. 4-20mA vs. Vel set up the CL output range from 4-20mA corresponding flow velocity
8. 4-20mA vs. Energy set up the CL output range from 4-20mA corresponding heat flow
20-4-20mA mode output 20-0-20mA mode output 0-20mA mode output
4-20mA mode output 0-4-20mA mode output Fluid velocity / 4-20mA mode output
-F20mA -F4mA F4mA F20mA
Flow Flow Flow Flow
24mA
Flow
Output current
-F20mA -F0mA F0mA F20mA
Flow Flow Flow Flow
24mA
Flow
Output current
F0mA F20mA
Flow Flow
24mA
Flow
Output current
20mA
F4mA F20mA
Flow Flow
24mA
Flow
Output current
20mA
4mA
F0mA F20mA
Flow Flow
24mA
Flow
Output current
20mA
4mA
F4mA F20mA
Fluid Fluid
Velocity Velocity
24mA
Fluid velocity
Output current
20mA
4mA
The Serial Port controls the output according to the command and parameter entered in the RS232 to output a
definite current value through the current loop. The command formats are narrated in the command explanations
to Serial Port controls. For example, if it is necessary to output a 6mA current through the current loop, it can be
realized by setting Window M56 to the mode
“
0-20mA Via RS232
”
and giving a command as
“
AO6 (CR)
”
. This
function is able to make the Flowmeter operate a control valve conveniently.
Other different current output characteristics are displayed in above figures. The user can select one of them
according to his actual requirements.
In six graphs shown above, flow F
0mA
or F
4mA
indicates the value that user entered in Window M57; and flow
F
20mA
indicates the value that customer entered in Window M58. In the 4-20mA and 0-20mA modes, F
0mA
(or
F
4mA
)and F
20mA
can be selected as a positive or negative flow value as long as the two values are not the same. As
for modes 20-4-20mA and 20-0-20mA, the Flowmeter ignores the positive and negative value of the actual flow;
therefore, both F
0mA
(or F
4mA
)and F
20mA
must be selected as positive flow values.
In mode 0-4-20mA, F
0mA
must be select as a negative value and F
20mA
as a positive value. Furthermore, in mode
4-20mA, the output current is indicated as velocity.