Table of Contents
Advertisement
502 010 05
reached, the output is switched off and the valve is closed or the pump stops. The Volume2
counter shows the dosed volume
2.3.2
Flow control
In systems where it is desirable to have a constant flow, the built-in Flow Control function may
be used to control a valve or pump directly. The required flow rate is keyed into a setpoint
register and the internal PI controller will control the valve or pump by means of the current
output signal (4-20 mA)
2.3.3
Limit switch
The Flow Transmitter has a built-in limit switch function. This function may be used to indicate
whether a measuring value is below or above the value in the setpoint register. As an exam-
ple, this may be used to indicate a high/low flow rate. The indication may appear on a digital
output, Output2, as ON or OFF
function for Output2).
2.4
Temperature measurement
The Flow Transmitter can measure temperature by connecting an external Pt100 tempera-
ture sensor. The temperature may be read in a register as °C or °F
tion selector
Code3). This would be necessary for temperature compensated flow measure-
ment.
2.5
Output1
Output1 is a power supply output, which can be used to supply nom. 24 V DC to an external
counter or relay circuit
2.6
Output2
Output2 can be selected for one of several functions:
•
Pulse signal, 0-10 Hz. The signal may be taken to a counter, electronic or electro-
mechanical, for indication of the total volume, e.g. in litres (see section 5.3.1 Output2).
•
Sign for Output3. The signal indicates the flow direction. The output is switched OFF,
when the flow is positive. By means of an UP/DOWN-counter, this signal may be used
for the totalizing of the volume flowing with a sign.
•
Control signal from the Batch control function.
•
Control signal from the Limit function.
•
Error free measurement signal. The output signal is ON if no error is present.
•
The output may be controlled directly via P-NET.
(See configuration of function selector
Further details for connecting Output2 can be found in section 5.3.1 Output2.
12/55
(see also the Batch control application
(see the Flow control application
(see configuration of function selector Code2
(see further details in section
Code2)
Flow Transmitter, PD 340
example).
example)
(see configuration of func-
5.2).
to select this
Manual
Advertisement
Table of Contents
