As we are more or less blind related to the suspension timing state and the data received by the DSP boards, we setup a test to check the Tolm paths between the DAQ room and terminal building through the MxDx_v1 network.

The basic idea is to send twice the same Tolm packet to the Sc_{N,W}E DSPs from the ISC_rtpc, but for the second one to return from the latest MxDx_v1 stage  before the receiving DSP to the SUSP_rtpc . To allow this

• the double transmission has been setup in the LSC_Acl_Moni server
• the  channel comparison has been setup in the TIMING_moni server

Today the Tolm packet send to NE and WE DSP contains the following channels

• TOLM_PROCESSOR_OUTPUT_PACKET_WITH_FREQUENCY    "LSCToSc_{N,W}E"    LSC_FREQ    0    ""    2    0x00 0x02 0x1F    0    LSC_DSP_FLAG
  TOLM_PROCESSOR_PACKET_APPEND                "LSCToSc_{N,W}E"    LSC_{N,W}E_LOCK_FLAG            LSC_{N,W}E_CORR                    LSC_B{7,8}_DC
  TOLM_PROCESSOR_PACKET_APPEND                "LSCToSc_{N,W}E"    LSC_ASC_{N,W}E_TX_ON_OUT        LSC_ASC_{N,W}E_TY_ON_OUT        LSC_ASC_{N,W}E_TX_CORR_OUT        LSC_ASC_{N,W}E_TY_CORR_OUT
  TOLM_PROCESSOR_PACKET_APPEND                "LSCToSc_{N,W}E"    LSC_ASC_{N,W}E_TX_NOISE_OUT        LSC_ASC_{N,W}E_TY_NOISE_OUT        LSC_{N,W}E_VIOLIN_OUT
  TOLM_PROCESSOR_PACKET_APPEND                "LSCToSc_{N,W}E"    LSC_CAL_{N,W}E_MIR_Z_CORR        LSC_CAL_{N,W}E_MAR_Z_CORR        LSC_CAL_{N,W}E_MIR_Z_NOISE

The channels comparison has been setup on a reduced set of channels

• LSC_{N,W}E_CORR different from zero only when the ARMS are locked
• LSC_B{7,8}_DC  always available and different from zero whatever the ITF state
• LSC_CAL_{N,W}E_MIR_Z_CORR   and  LSC_CAL_{N,W}E_MAR_Z_CORR always available and different from zero whatever the ITF state

The channels used as reference as labelled with the suffix  _REF , the ones related to the round trip  with _RT and the difference between the 2 channels is  LSC_diff_REF_RT_* (see this plot) .

All these new channels are stored in the RAW_FULL stream with the _FS suffix

Issues after these operations

When this new data path was put in operation, a mistake was made by using the same Tolm packet name with a new prefix for the ones forwarded  from the ISC_rtpc to SUSP_rtpc and the ones sent to the Sc_{N,W}E DSPs. As a consequence, the Tolm page header changed, so the data was not anymore handled at  the DSP's side

To recover the situation, the 2 different names are used and the SUSPENSION experts (mainly Paolo) had to update the setup.dat and recompile the DSP codes to use the new Tolm Page descriptor