Brooks Instrument SLAMf Series - Manual (Page 36)

3-2
Section 3 Operation Installation and Operation Manual
X-TMF-SLAMf-MFC-eng
Part Number: 541B032AAG
April, 2013
Brooks ® Digital MFC's and MFM's
DT = A x P x Cp x m
Where,
DT = Temperature difference T2 - T1 (°K)
A = Constant of proportionality (s
2 -°K 2 /kJ 2 )
P = Heater Power (kJ/s)
Cp = specific heat of the gas at constant pressure (kJ/kg - °K)
m = Mass Flow (kg/s)
A bridge circuit and a differential amplifier interpret the temperature difference
and generate an electrical signal directly proportional to the gas mass flow
rate.
3-3 Features
Note: All Brooks SLAMf Digital Series mass flow meters are configured at
the factory according to customer order and do not require adjustment. Not
all features are available on all instruments.
The Brooks SLAMfDigital is a full-featured digital MFC. The Brooks SLAMf
Digital performs much like a traditional analog MFC, but with improved
accuracy, step response and valve control. The analog interface matches
that of Brooks' popular analog MFCs so it can be retrofitted into tools using
analog MFCs. Other versions of the SLAMf Series can provide a variety of
digital protocols, for example DeviceNet and RS-485.
The Brooks SLAMf Digital equipment is capable of storing up to 10
different sets of gas calibration data. Each set includes a calibration curve,
PID controller settings, valve performance data, and information about the
calibration conditions. The Brooks SLAMf Digital equipment can contain
calibrations for different gases or for the same gas at multiple conditions
(pressures, full-scale flow rates). Section 3-4 Analog I/O Mode of
Operation describes more information about the data contained in the
calibration table and how to access the data.
The DeviceNet Instruction Manual describes further details on specific
communication features.
Calibrations will appear in the calibration table in the same order as they
appeared on the customer order, unless otherwise specified. The first
listed gas will appear as calibration #1 the second as calibration #2 and so
on. Note that unless specified otherwise on the customer order any unit
containing a single calibration will have that calibration stored in calibration
position 1.