A&G Box TFR workaround

We strongly suspect that the stepper motor driving the slide with the TV barrels attached (TV focal reducers) is loosing steps.

With ISIS we need the 18"/mm optics in front of AG4 in order to view the whole ISIS slit. TFR in position 1.

With all other CASS instruments we need NO barrel. This corresponds to TFR in initialised position. TFR in position 0.

There is a 2nd barrel in position 2 for 12"/mm direct viewing. This position is not required until further notice.

 

After a CASS instrument change, once TFR is in the required position, the red marked cable PL50 (TV focal reducer) is disconnected from the A&G box. Thus for moving you need to reconnect this cable! Once TFR is in the required position the cable needs disconnecting again!

 

For ISIS slit viewing issue the following commands from the engineering terminal:

  • TFR102
  • TFR101(1)
  • after this movement check using 'TFR SEE' you see: Target 1, Step count 6410, Switches 2

    Note: With ISIS direct viewing is not available anymore. This is not a problem. A 7 star calibrate can aswell be done accurately using slit viewing.

     

    For direct viewing with all other CASS instruments (not ISIS), all you need is issuing:

  • TFR102

    •  

    This file: http://www.ing.iac.es/~eng/ops/wht/AGbox_TFR_workaround.htm
    Jürg Rey, 29 December, 2007