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Figure 13. NI DAQ.
To read the pressures gauges of the GHS, the CU is equipped with a Pfeiffer
Vacuum GmbH 6-channel pressure controller unit (MaxiGauge, model TPG 256).
This is a completely separate unit within the CU. For remote operation the RS232
output is converted to USB (with a converter from FTDI, model US232r-10), which
connects to the central USB-hub (see Figure 10). For more details, see also Section
5.2.
Finally the CU contains a small auxiliary circuit board to facilitate the readout of the
flow meter (see Figure 10). The flow meter circuit board and connection scheme are
given in Attachment 7.6. As shown, the output voltage of the flow meter is fed
directly into the analog input of the NI-DAQ. The voltage is converted to flow with the
calibration factor given in the Performance Sheet and Calibration Report, which is
supplied as separate document to your system. The LED display on the front panel
is a voltmeter that is calibrated to show flow in mmol/s by adjusting the trimmer R3
(see Attachment 7.6). Note: because of the good thermal anchoring between the
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System description |
BlueFors Cryogenics Ltd – BF-H400