MCA Data Server Reference

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ARM Data structures

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MCA Data Server

Overview

Neutron-3K Data Structure: arm_status

Summary

The arm_status data structure reports data describing the current status of the slow-control system. Data reported include the operating voltage (SiPM-3000), temperatures and more.

Data structures

For arm_status there are seven 'register' and 'field' data in use. All register data are 32-bit floats (float32).

arm_status registers and fields — slow control and operation
Register number and field nameDescription
AS0: op_voltageCurrent operating voltage (SiPM only)
AS1: voltage_targetComputed target voltage from request (directly or with correction applied)
AS2: set_voltageCurrent operating voltage set by the DAC (so that op_voltage matches req_volt (directly or with correction applied; SiPM only))
AS3: cpu_temperatureCurrent ARM M0+ processor core temperature
AS4: x_temperatureCurrent temperature measured by the external temperature sensor at the PMT or SiPM.
AS5: avg_temperatureCurrent temperature average (from selected sensor)
AS6: dg_targetTarget digital gain (reserved)
AS7: led_targetComputed LED value target, for systems with LED.
AS8: wall_clock_timewall_clock time; Resolution is 65536/48MHz=1.365ms when wall_clock_time < 224; ie 22906 s
AS9: op_statusBitfield, operation status; cf user table below
AS10: supply_voltageMeasured USB supply voltage
AS11: fpga_countNumber of FPGA reboots since power on
AS12: led_valueMeasured LED value from FPGA, for systems with an LED.
AS13: dc_offsetDC-offset in mV (90<DC<130)
AS14: anode_currentPMT or SiPM DC anode current.
The arm_status registers concerning slow control and operation.

There is only one higher-level 'user' dictionary entry for arm_status operation.

arm_version user dictionary
NameDescription
wall_clock_timeWall clock time in seconds; Resolution is 1.365ms.
fpga_status1 ⇒ FPGA is booted
alarm_status1 ⇒ Active alarm
arm_status 'user' dictionary entries concerning operation and slow control.
arm_status registers and fields — sample measurement: count rates and statistics
Register number and field nameDescription
AS15: run_time_sampleRun time of the sample measurement; resolution is 1.6384ms. This has been corrected for the measured dead time: run_time = real_time−dead_time.
AS16: eventsNumber of sample events
AS17: trigger_rateTrigger rate in cps
AS18: dead_timeMeasured dead time
AS19: count_rateSample count rate
AS20: count_rate_errSample count rate 2-σ error computed using Poisson statistics.
The arm_status registers concerning measuring a sample
arm_status registers and fields — background measurement: count rates and statistics
Register number and field nameDescription
AS21: run_time_bckRun time of the background measurement; resolution is 1.6384ms. This has been corrected for the measured dead time: run_time = real_time−dead_time.
AS22: events_bckNumber of background events
AS23: trigger_rate_bckTrigger rate in cps
AS24: dead_time_bckMeasured dead time
AS25: count_rate_bckBackground count rate
AS26: count_rate_bck_errBackground count rate 2-σ error computed using Poisson statistics.
The arm_status registers concerning measuring the background.
arm_status registers and fields — sample − background measurement: count rates and analysis
Register number and field nameDescription
AS27: count_rate_diffSample − Background count rate
AS28: count_rate_diff_errDifference count rate 2-σ error computed using Poisson statistics.
AS29: bck_probabilityProbability that the sample count rate is caused by the measured background rate.
AS30: bck_low_probabilityMost alarmist: P(counts > N+sigma(N) | mu-sigma(mu))
AS31: bck_high_probabilityMost cautious: P(counts > N-sigma(N) | mu+sigma(mu))
AS32: alarm_timeAlarm count down until alarm turns off when alarm_time = 0_seconds
The arm_status registers concerning measuring sample − background and the statistical analysis.
arm_status registers and fields — portal monitor alarms
Register number and field nameDescription
AS33: ts_readyPortal monitor alarming system is ready
AS34: ts_alarm>0 if there is an active alarm
AS35: ts_netNet counts above background during the last L time slices
AS36: ts_bckBackground counts above background during the last L time slices
AS37: ts_probProbability that ts_net is caused by the accepted background rate.
AS38: ts_resetTime slice counters were reset due to an extended alarm (longer than arm_ctrl[AC_TS_H])
The arm_status registers concerning portal monitor operation and statistical analysis.