Tecfluid MT-02 - Manual (Page 6)

6
Cod.:E-MI-2151001I Rev.: 2
From this situation we can do one of two things:
1. Press again the ON/OFF" [3] push-button and the process will continue from where it was stopped.
2. Press the "
∆" [6] push-button and the instrument will go to MODE "0", aborting the process.
In the event that there has been a mains failure during a batching process, when the mains
comes back the MT-02 will automatically go to MODE "1" with the display blinking. We can use one of
the previous two options to continue the batch or abort.
The counters are always working in modes "0" and "1", and therefor if the elements which cut off
the flow are slow-acting, one can find that the partial counter may indicate a little more volume than was
programmed for the batch.
4 TOTALIZING
COUNTER
The totalizing counter shows the total volume that has passed through the flowmeter,
independently of the use or not of the batching option.
To visualize the value of the totalizing counter, whilst in MODE "0", we must press the " ∆" [6]
push-button and the MODE indicator will go to "2", indicating that the value displayed is the total volume.
To get back to mode "0" without clearing the totalizing counter we must press the " ∆" [6] push-
button.
To clear the totalizing counter, whilst in MODE "2" we must press "PROG" [4] and "ENTER" [5]
at the same time, and the instrument will automatically go back to mode "0".
5
USEFUL EXAMPLES OF CALCULATIONS
Measurement error corrections
The calibration of the mechanical flowmeters is realized using, for the liquid, water at 20
o
C thus
obtaining a calibration for a liquid of density 1 kg/l and viscosity of 1 mPas. If the flowmeter is used with a
liquid of other characteristics from the above specified o for reasons of turbulences in the flow,
measurement errors can be induced.
To correct these types of errors we can modify the litres per pulse programmed in the MT-02.
Example 1 - Shortage of volume
If we have a flowmeter which specifies 200 pulses per litre, and when we check the volume of a
batch, we find that instead of having 100 litres as programmed, we only have 95 litres (5% less) and we
must apply the following correction:
Fn = Factor Pulses per litre ( new )
= ? (210,526)
F = Factor pulses per litre ( original ) = 200
V = Expected Volume = 100
Vr = Real Volume = 95
V
V x F
= F
r
n
In this case counting 200 pulses per litre for 100 litres (total of 20.000 pulses) we have been
given in fact 95 litres, thus we must increase the value of pulses per litre to 210,526.
We must then calculate the reciprocal of this new value to introduce in the "L" mode.
Example 2 - Excess of volume
If we have a flowmeter which specifies 200 pulses per litre, and when we check the volume of a
batch, we find that instead of having 100 litres as programmed, we only have 105 litres (5% more) and