See the molbox1+ (or molbox1) manual and the below diagram to compare two molbloc elements in A/B mode. This can be useful to check your mobloc elements between calibrations.
The below example is with two laminar molbloc elements with low pressure calibrations. Remember that each molbloc must remain within its pressure requirements based on its calibration type (low pressure, high pressure or downstream). See these quick start guides for more information on the calibration types.
Set the stability setting on the molbox1+ to a value that is lower than the uncertainty of the molbloc at the flow rate. A standard class calibration is 0.2% of reading down to 10%FS. At 100 sccm, this is 0.2 sccm. Set the stability setting to 0.05 sccm at this menu path; Setup --> Stability
This slows down the switching of the channels enough so that a valid comparison can be made. In A/B mode the molbox1+ display will show you the ratio of the flow rates and the value should be within 0.998 to 1.002 for a standard class calibrated molbloc and within 0.99875 to 1.00125 for a premium class calibrated molbloc.
Note that this cannot be done with a molbox RFM because it only has one channel and cannot do A/B mode.