TESTO 0699 6446 Series, Instruction Manual

Page: 35 / 44

6 Operation
35
Display unit
3 settings can be selected:
•
Lmin = Flow in Nl/min or Nm³/min
•
nm3h = Flow in Nm³/h or Nm³/h x 1000
•
nm3 = Quantity counter in standard cubic metres
Set the display unit before you set the values for the
SPx, rPx, ASP and AEP parameters. That way you
avoid rounding up/down errors in the internal conver-
sion into other units and are provided with exactly the
values required.
Hysteresis function
The hysteresis keeps the switch status of the output
stable if the flow is fluctuating around the nominal
value.
With increasing flow, the output switches upon reach-
ing the switch point (SPx).
If the flow decreases again, the output only switches
back when the return switch point (rPx) is reached.
The hysteresis is adjustable:
First the switch point is determined, then the return
switch point at the desired distance.
Window function
The window function allows a defined OK range to be
monitored.
If the flow is fluctuating between switch point (SPx)
and return switch point (rPx), the output is switched
through (window function/NO contact) or opened
(window function/NC contact).
The size of the window is adjustable by the distance
between SPx and rPx.
SPx = upper value; rPx = lower value.
Hysteresis
OK range