PXL Detector slow control data and pathways



03/02/2012LG, JSDRAFTPXL Detector slow control data and pathwaysThe slow control and monitoring pathways and data to be logged/acted upon are broken down by the interfaces into the PXL system. The primary function of the slow control and monitoring system is to monitor and log the status of the PXL detector and to alarm or take automated action in the case that an error is sufficiently critical. This is independent of an interlock system such as the one being envisioned for the cooling system.The main interface for slow controls data logging will be the existing EPICS based slow controls system of STAR. The STAR slow controls group is evaluating the use of CSS as a new tool set for EPICS. If the development is sufficiently advanced by the time PXL needs to write the slow controls GUIs, this toolset will be used. The interface API for getting variables into EPICS will likely be EPICS’s “Channel Access” calls from a PXL controls PC (Linux?).USB interface to RDO motherboards:The USB interface to the RDO motherboards operates in parallel with the DDL RDO system but passes only information of interest to the monitoring PC. These monitoring events contain status registers that indicate the status of the RDO system and the temperature of two sensors per ladder. These counters will be reset when sent. The following counters and their readout frequency have so far been defined .The data will include:(I am just making things up here, let’s iterate on those):CounterFrequencyEvent Counter1 secSIU error1 secSync error between internal clock and frame boundary1 secLatch-up events1 secBusy Counter1 secSome of the other variables mentioned above would still be instantaneous values, but read out at a lower frequency as well:Sensor temp 1 secFirmware SEU’s1 secFixed values like “Firmware version” will only be read out on demand, not periodically.The architecture of the USB based monitoring system is shown schematically below:Figure 1 The PXL USB connection slow control architecture. The fiber optic couplers isolate platform ground from the RDO boards.CANBUS to the RDO crateThe CANBUS is used to power on/off the RDO crate and log the voltages, current and temperature of the RDO crate.State+5V current+5V voltageCrate temperatureThis interface will be using existing software from STAR Slow Controls that currently controls other VME crates in STAR.PXL MTB/sector power supplyThe power supply for the PXL MTB/sector is not yet defined. We will purchase a power supply that has a control interface which will need to be interfaced to the STAR slow control system. The interface will allow for the remote power on/off of the supply and will allow for the readout of the following data:State+6V current+6V voltagePS temperature TOF is successfully using Power supplies from “Wiener” (Model PL512), which have both a USB and an Ethernet controls interface. The Ethernet interface uses SNMP to control and monitor the supplies. TOF has written EPICS interface code (“IOC”) and GUI code (MEDM) to control and monitor these crates from EPICS.Here is an example (MEDM) GUI from TOF:Cooling system and cooling system sensorsThe cooling system SC path will allow for the powering on/off of the PXL air cooling system. The flow sensors are expected to be interlocked with the AC power to the PXL MTB/sector power supply. The data to be collected is expected to include:StatusAirflow inletAirflow outletTemperature inletTemperature outletPressure inlet?Pressure outlet?We will rely on existing EPICS code to monitor these sensors. These systems will only monitor and alarm from within EPICS, since they are critical systems and thus are interlocked with the STAR safety system. ................
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