Accessing the screen

The GMD main screen already shows the most recent calculation of the photon beam energy made with data from Keithley. One of the chart lines also shows the last 256 seconds of energy calculated by Keithley. To access a screen with more details, click on the button called Keithley.

Keithley main screen

Below the chart, on the left, there's a group with data that is used to calculate the photon beam energy:

1. SXR repetition rate, from the accelerator.
2. Wavelength, from the accelerator.
3. Keithley's current sum, from the Keithley itself.
4.  Temperature, from the sensor that is touching the outside area of the chamber. A PLC is responsible to read the temperature and expose it as an EPICS PV.
5. Pressure, from the Spinning Rotor Gauge (SRG), controlled by another IOC.
6. Cross-section and mean charge come from tables, in txt format, that are part of the IOC. These tables were provided by the GMD vendor. The GMD IOC gets the type of gas that is in the chamber and the wavelength to select the right values for the cross-section and mean charge.

The mean charge and cross-section can be manually typed on the screen in the bottom right in case a problem happens when retrieving the gas type from the SRG IOC.

The calculated values are shown below the chart, on the right.

Clicking on the Keithley 1 (or 2) button opens the screen from the Keithley IOC.

Difference between GMD and XGMD

The GMD has only one Keithley, while the XGMD has two. The screen always shows the buttons Keithley 1 and Keithley 2, no matter if it refers to the GMD or XGMD. In a future version of the software, this will be fixed.

The parameter Keithley's current sum shown on screen is the sum of the two Keithley currents in the case of the XGMD or the direct reading of the only Keithley in the GMD.

Known problems with the Keithley