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DMA4500m Density Meter

Cosimo Campo edited this page Apr 8, 2020 · 17 revisions

Wiki > The Backend System > Specific Device IOC > Gas and liquid handling systems > DMA4500m Density Meter

The device's IOC was originally developed at ESS, then updated to match ISIS requirements and conventions. The original code is available here.

It is a densitometer which currently measures density and temperature.

Documentation

Vendor documentation is available at \\ISIS\shares\ISIS_Experiment_Controls\Manuals\AntonPaar__DMA4500.

Connection Details

RS-232C Specifications
Baud rate 9600 Baud
Stop bits 1 bit
Parity None
Data length 8 bit
Flow control None

Notes:

  • Commands and returned values are terminated with CR
  • Only one command should be sent per second

Simulation

The IOC logic is fairly complex and uses features not supported by RECSIM, so RECSIM has not been implemented for this device.

Measurement Mode

The data sent back by the device is parsed according to the current measurement mode, which is set by $(MEASUREMENT_MODE) macro. Currently, the only supported mode is DENSITY_ONLY (for measuring density, temperature and measurement validity).

From the device's point of view, the measurement results are returned by the getdata command. The quantities to be measured and their position in the results list are determined by the active "method". Methods are defined by the user using the device's GUI, and they can include a large number of different quantities in any order specified by the user. The device does offer a getdatahead command to get the name and position of the quantities returned by getdata, but there is no easy way of parsing the output of this command to automatically make sense of the results list. For this reason, we need to manually add a measurement mode for every method used at ISIS, and users must make sure to set the $(MEASUREMENT_MODE) macro in IBEX to match the method they're using.

IOC diagram:

Diagram of DMA4500M IOC

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