Brooks Instrument BM50 - Manual (Page 36)

3-12
Section 3 Operation Installation and Operation Manual
X-PD-BM-Ovals-eng
Part Number: 541B031AAG
January, 2009
BM Oval Series
3-8 Deluxe LCD Display Description
Normal Operation
The quantity of liquid passing through the meter will be measured and
displayed (partial quantity counter). No additional devices are required.
Automatic Operation (Presettable Batch Controller)
A preset quantity can be transferred in automatic operation. In order to
control valves, the motor of the pump and/or other similar devices by the
meter, an amplifier according to NAMUR signals is required. The amplifier
transforms the control signal from the meter into relay signals.
For transferring foaming liquids or if shock pressures are too high;
The meter enables a measuring operation of a liquid in three steps. For
this it is necessary to use two valves.
Step 1: Both valves are open
Step 2: One valve closes (precise measuring operations starts).
Step 3: The second valve closes
1 amplifier with 2 output signals, 2 valves and a regulating valve are
required.
Leakage Quantity (Time lag of valves)
If the "OFF" signal (close) is displayed, there will be a time lag before the
valve will be closed. During this time an unknown quantity of liquid will pass
through the meter. This quantity is called leakage quantity. The leakage
quantity is measured by the meter during each measuring operation and it
is taken into account when starting the next measuring operation.
Note: The current leakage quantity always depends on the previous measuring
operation.
Factory Calibration
Factory calibration is not protected and can be changed by the user.
Calibration constant is entered prior to shipment.
Presignal Quantity:
The set presignal quantity is valid for all preset quantities.
The presignal quantity can be set between 0.0 and 9.9 Liters/Gallons.
(Relative Automatic Operation)
Cycle Counter:
No overflow indication (the counter starts again at zero).
If the preset quantity is changed, this counter willreset to zero automatically