Double Pass Calibration article image July 2021

Calibrating – Double Pass Emission Monitors

Acoem Dynoptic’s double pass dust and particulate monitors are designed to operate using open path, optical technology. To conclude the installation process, the operator must perform an in-situ calibration and commissioning of the monitor. This is true for every installation, as we are unable to manufacture and supply monitors pre-calibrated due to the physical variations between each individual application.

Below is a summary of the steps required to successfully commission a Dynoptic double pass dust or particulate monitor, these steps are in order starting with the head alignment.

  1. Perform head alignment – This optimizes the mounting angle of the TRX and Reflector heads to achieve the largest possible measured signal.
  2. Perform an Automatic Gain Correction – This adjusts the gain applied to the measurement signal to achieve an amplified signal that is within the required voltage range.
  3. Perform a Zero Adjust – adjust the zero to 0.0mg/m3 under clear path conditions (IE the process must not be running). This adjusts the instruments span setting to define 0.0mg/m3.
  4. Define the Path Length – An accurate path length, defined as the distance (in metres) between the face of the flange on the air purge body of the TRX, and at the same point on the air purge body of the reflector head must be input to within +/- 0.05m.
  5. Perform an Upscale Calibration – The particulate monitor must be calibrated to an independent reference measurement, such as isokinetic sampling. The calibration requires a density scale factor to be input into the utility software, this process can only be completed with the monitor installed in-situ.
  6. Configure the outputs – Once the instrument is calibrated the current output and level alarm can be configured as required for integration with the wider plant systems.

Dynoptic monitors have a range of design features and optional accessories to help with this process, including

  • A laser alignment tool to simplify physical head alignment
  • Easy to use utility software with signal strength indicators (included with all monitors as standard).
  • Compression gaskets, in conjunction with mounting nuts, to fine tune alignment
  • Calibration heads, zero mirrors and opacity filters.

Our monitors are supplied with comprehensive installation and operator manuals which provide a high level of detail along with clear illustrations. All our customers are welcome to contact us directly, video conference training sessions can be arranged when remote support is required.

If you have any questions or would like more information about our range of Opacity, Dust and Particulate monitors please contact us directly.  +44(0)1280 850521,

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