The arm_status data structure reports data describing the current status of the slow-control system. Data reported include the count rates, alarm probabilities and more. Valid for PMT-based and SiPM-based MCA-2K devices such as PMT-2000, SiPM-2000.
For arm_status these are the 'register' and 'field' data in use. All register data are 32-bit floats (float32).
arm_status registers and fields |
Register number and field name | Description |
AS0: op_voltage | PMT-2000: always 0. SiPM-2000 only: Current SiPM operating voltage; cf note 1. |
AS1: target_volt | Reads arm_ctrl["cal_ov"] when gain stabilization is off; Reads a computed target voltage when gain stabilization is on; cf note 1. |
AS2: set_voltage | PMT-2000: always 0. SiPM-2000 only: Current operating voltage set by the DAC to achieve the op_voltage, cf note 1. |
AS3: target_dg | Reads arm_ctrl["cal_dg"] when gain stabilization is off; Reads a computed target digital gain when gain stabilization is on; cf note 1. Reserved for future use. |
AS4: cpu_temperature | Current ARM M0+ processor core temperature |
AS5: x_temperature | PMT-2000: Current temperature of the high voltage unit. It is close to the PMT temperature. SiPM-2000: Current SiPM temperature measured by a sensor adjacent to the SiPM. |
AS6: avg_temperature | Current temperature average (from selected sensor) |
AS7: | wall_clock time; Resolution is 65536/48MHz=1.365ms. Because these are float32 numbers delivered by the PMT-MCA, this field has only 23 mantissa bits and stops incrementing at 223; ie after 11453 s = 3.18 hours. (The field is repeated in the histogram data structure with full 32-bit precision, rolling over only after 67.9days.) |
AS8: run_status | Run status, a bit-field. |
AS8[0]: histo_active | Indicates if histogram acquisition is ongoing. |
AS8[1]: alarm_active | Indicates if the alarming algorithm is active. |
AS9: run_time | Run time of the foreground counter (resolution: 1.365333ms) |
AS10: count_rate | Foreground or sample count rate |
AS11: count_rate_err | Foreground count rate 2-σ error |
AS12: run_time_bck | Run time of the background counter (resolution: 1.365333ms) |
AS13: count_rate_bck | Background count rate |
AS14: count_rate_bck_err | Background count rate 2-σ error |
AS15: count_rate_diff | Foreground minus background count rate |
AS16: count_rate_diff_err | Foreground minus background count rate 2-σ error |
AS17: background_probability | Probability that the foreground counts are caused by the measured background rate. |
AS18: bck_low_probability | Most alarmist chance that the sample (S) is more radioactive than the background (B): P(counts > S+sigma(S) | B-sigma(B)) |
AS19: bck_high_probability | Most cautious chance that the sample (S) is more radioactive than the background (B): P(counts > S-sigma(S) | B+sigma(B)) |
All arm_status registers and fields. Note 1: Parameter reads back zero when the lock-bit is set in arm_cal, LUT[63].
When comparing the activity of a sample against the background activity, the results will be reported in the fields shown below. The region of interest (ROI) is encoded in arm_ctrl at AC17, AC18: roi_low, roi_high.
arm_status user dictionary |
Name | Description |
wall_clock_time | Wall clock time in seconds; Resolution is 1.365ms. |
counter_active | Histogram is updating; 0 or 1 |
active_bank | Number of the histogram bank that is updating; 0 or 1 |
trace_done | 1 → FPGA trace acquisition is complete. |
listmode_done | 1 → The FPGA has filled a listmode buffer with the maximum number of events. |
flash_busy | 1 → The SPI flash memory is still busy from a previous write. This typically takes a few dozen milli-seconds. |
fpga_fail | 1 → The FPGA did not boot. |
power_fail | Under voltage warning: 1 → The 5V supply is below the safe limit. |
arm_status 'user' dictionary entries