3.5
How is the flow rate measurement activated?
The TD 8250 can be switched to flow or volume measurement. This will be made by pro-
gramming TD 8250 under menu “
7
” at step “
display
”. The flow rate will be adjusted by
“
0
” and the volume by “
1
” (
§ 4.1 "Overview of the input values").
As soon as a medium flows through the flow sensor, a flow rate indication appears. No
special action is required. The instantaneous flow rate is indicated, usually in litres per min-
ute.
The TD 8250 must be adjusted to the actual flow sensor that is connected. The procedure
is given in § 4.2 "What must be programmed when connecting a flow sensor?".
3.6
How is the volume measurement activated?
The TD 8250 can be switched to flow measurement or volume measurement. This will be
made by programming TD 8250 under menu “
7
” at step “
display
”. The flow rate will be
adjusted by “
0
” and the volume by “
1
” (
§ 4.1 "Overview of the input values").
By volumetric measurement is implied the summation of the amount of a medium which has
flowed through a flow sensor. Usually the indication is in litres.
When the limiting frequency has been passed and a release signal has been given a
summation will be made. To program limiting frequency under menu „
10
“ you have to
take the flow sensor’s impulse frequency in hertz (Hz). Usually the limiting frequency has
to be set to 0.000.
Connection of release signal output has to be made on the terminal:
Terminal :
summation
enable
(yellow)
If there is a voltage of 24 V at the enable input, summation of the volume commences.
The measured values on the display change.
If there is a voltage of 0 V at the enable input, summation of the volume is stopped. The
measured values on the display do not change.
When the voltage at the enable input is changed from 0 V to 24 V the summation is reset
to zero. The determination of the volume starts again.
3.7
Error display
On two channel flow sensors it is possible to monitor the correct pulse sequence on the
channels. Faulty pulses are not counted and thus do not change the volume measurement.
If an error is established by the TD 8250, the character sequence “
FAUL
“ appears in the dis-
play.
The error display can also be completely deactivated. This is carried out under the menu
reference “
08
“ at the
“ counter input“
position. The error display is enabled with a
“0”
and blocked with a
“1”
(
§ 4.1 "Overview of the input values").
