Fluke molbox RFM Reference Flow Monitor

molbloc flow elements are connected to molbox RFM Flow Monitors with two pressure connections and one data line.

molbox RFM Flow Monitors are support units for making mass flow measurements using molbloc-L laminar and molbloc-S sonic flow elements.

molbloc flow elements are connected to molbox RFM Flow Monitors with two pressure connections and one data line. molbox RFM Flow Monitors read calibration data off the molbloc EEPROM and measures molbloc upstream and downstream pressure with a built-in high accuracy Reference Pressure Transducers (RPTs). An ohmic measurement system reads the resistance of the molbloc platinum resistance thermometers from which molbloc temperature is calculated. Using the molbloc calibration data, pressures, temperature and gas properties stored in molbox RFM memory, the flow rate of the gas flowing through the molbloc is calculated. For molbloc-L flow elements, a microrange option is available to increase flow measurement resolution and accuracy under 10 % FS of the flow range. molbox RFM and molbloc flow elements are useful in a variety of measurement, test and calibration applications in which highly accurate measurement of low gas flows is needed. molbox RFM is specifically designed for applications in which a highly compact presentation, great rangeability and reduced cost are the primary considerations. A second model, molbox1+, is available for applications in which lowest possible uncertainty is the top priority. To configure your mass flow calibration system, see the pages that follow to select the molbloc and pressure dependent calibrations to best cover your flow ranges and pressure conditions. molstic mounting systems and COMPASS® for molbox Flow calibration software are available to complete the system.

  • Compact presentation
  • Covers the flow range of 1 sccm to 100 slm with molbloc-L, and up to 5000 slm with molbloc-S
  • Select from 20 different gases
  • Accredited measurement uncertainty of ± 0.5 % of reading with up to 100:1 rangeability
  • Internal valving for on-board purge, leak test and tare support
  • Includes advanced measurement functions such as totalize, average, hi/lo and deviation
  • Complete front panel control and RS232 and IEEE-488 remote communications
  • Measures mass and volume flow with user setable reference pressure and temperature conditions

 

Flow Measurement Specifications

molbox RFM measures the flow through molbloc flow elements. The flow range, usable operating pressure, and differential pressure for molbloc-L, or the flow range and absolute pressure range for molbloc-S, depend on the molbloc element used and its calibration options. See the molbloc-L and molbloc-S range sheets for calibration and range details. For molbloc-L ranges up to 3E4, the resolution and accuracy under 10% FS are improved by the microrange option. For the 1E5-L molbloc, the microrange option is necessary to achieve the specification.

molbox RFM Reference Flow Monitors

  molbloc-L (ranges 1E1-L thru 3E4-L) molbloc-S (all ranges)
Measurement update rate   1 second 1 second
Range to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L range sheet) The flow related to 20 kPa to 200 kPa absolute (3 psia to 30 psia) or 50 kPa to 500 kPa absolute (7 psia to 70 psia) upstream (see molbloc-S range sheet)
Resolution 0.01 % FS ± 0.01 % of reading
Linearity ± 0.23 % of reading from 10 % to 100 % FS, ± 0.023 % FS under 10 % FS ± 0.25 % of reading
Repeatability ± 0.1% of reading from 10 % to 100 % FS, ± 0.01% FS under 10 % FS ± 0.1 % of reading
Precision1 ± 0.25 % of reading from 10 % to 100 % FS, ± 0.025 % FS under 10 % FS ± 0.3 % of reading
Predicted stability2 (one year) ± 0.15 % of reading from 10 % to 100 % FS, ± 0.015 % FS under 10 % FS ± 0.2 % of reading
Measurement uncertainty3   ± 0.5 % of reading from 10 % to 100 % FS, ± 0.05 % FS under 10 % FS ± 0.5 % of reading from 50 kPa to 500 kPa, ± 0.5 % of the flow @ 50 kPa from 20 kPa to 50 kPa

molbox RFM with Microrange option

  molbloc-L (ranges 1E1-L thru 3E4-L) molbloc-L (ranges 1E5 only)
Measurement update rate 1 second 1 second
Range 0 to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L tables) 0 to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L tables)
Resolution 0.01 % FS, 0.001 % FS under 10 % FS 0.01 % FS
Linearity ± 0.23 % of reading from 1 % to 100 % FS, ± 0.0023 % FS under 1 % FS ± 0.25 % of reading from 5 % to 100 % FS, ± 0.0125 % FS under 5 % FS
Repeatability ± 0.1 % of reading from 1 % to 100 % FS, ± 0.001 % FS under 1 % FS ± 0.2 % of reading from 5 % to 100 % FS, ± 0.01 % FS under 5% FS
Precision1 ± 0.25 % of reading from 1 % to 100 % FS, ± 0.0025 % FS under 1% FS ± 0.32 % of reading from 5 % to 100 % FS, ± 0.016 % FS under 5 % FS
Predicted stability2 (one year) ± 0.15 % of reading from 1 % to 100 % FS, ± 0.0015 % FS under 1 % FS ± 0.2 % of reading from 5 % to 100 % FS, ± 0.01 % FS under 5 % FS
Measurement uncertainty3 ± 0.5 % of reading from 1 % to 100 % FS, ± 0.005 % FS under 1 % FS ± 0.5 % of reading from 5 % to 100 % FS, ± 0.025 % FS under 5 % FS

molbloc-S (all ranges)

Specifications are the same as a molbox RFM without Microrange. The Microrange transducer is disabled whenever the molbox RFM is connected to a molbloc-S. 1 Precision: Combined linearity, hysteresis, repeatability. 2 Predicted Stability: Maximum change in zero and span over one year for typical molbox RFM and molbloc used under typical conditions. As stability can only be predicted, stability for a specific molbox RFM should be established from experience. 3 Measurement Uncertainty: Maximum deviation of the molbox RFM flow indication from the true value of the flow through the molbloc including precision, stability and DHI calibration standard uncertainty. Measurement uncertainty specifications for molblocs are valid only for gases with which the molbloc has been calibrated. All molblocs are calibrated for N2. Calibrations with other gases are optional. DHI calibration capability is not maintained at all times for all gases on all molbloc designations. Check for availability before ordering.

 

Model Name

Description

molbox RFM molbox RFM Reference flow monitor Includes: Users manual, calibration certificate, power cord, (2) molbox RFM to molbloc pressure lines, (1) molbox RFM to molbloc data line, (2) Straight through pressure quick connectors

Accessories common to all models:

Accessory

Description

MFC-CB Control Box Includes: (2) MFC/MFM connection cable kits Calibration cable Power cord Operation and maintenance manual Calibration report
COMPASS for molbox software Calibration assistance software for molbloc/molbox users
molstic-L Mounting Systems For molbloc-L Mass Flow Elements
molstic-S Mounting System For molbloc-S Mass Flow Elements
RFM-RMK Rack mount kit
RFM 02 Microrange
 

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