From a8a01ae53d58f1d5fd761f3ac1cd82a29c33f025 Mon Sep 17 00:00:00 2001 From: John Segrave Date: Wed, 28 Oct 2020 22:05:12 +0000 Subject: [PATCH] Sensors can now report 'range exceeded', so the config-checker code no longer needs to *enforce* the 'limits should be at least double the sensor range' as a safety constraint. (However they do still *recommend* it, via a warning). --- src/GasExposureAnalytics.py | 33 +++++++++++++++++++++------------ 1 file changed, 21 insertions(+), 12 deletions(-) diff --git a/src/GasExposureAnalytics.py b/src/GasExposureAnalytics.py index 1ef3749..1687f4a 100644 --- a/src/GasExposureAnalytics.py +++ b/src/GasExposureAnalytics.py @@ -89,24 +89,33 @@ def _validate_config(self, config_filename) : critical_config_issues += [message] # For each supported gas, check that limits PPM configuration is within that sensor's range. - # The limits should be no less than double the range of the sensor. To to illustrate why: - # Say a firefighter experiences [30mins at 1ppm. Then 30mins at 25ppm] and the 1hr limit is 10ppm. Then one - # hour into the fire, this firefighter has experienced an average of 13ppm per hour, well over the 10ppm + # The limits must be less than the range of the sensor. For best reporting, the range should be at least + # two or more times the upper limit and a warning will be produced if this is not the case. To to illustrate + # why: Say a firefighter experiences [30mins at 1ppm. Then 30mins at 25ppm] and the 1hr limit is 10ppm. Then + # one hour into the fire, this firefighter has experienced an average of 13ppm per hour, well over the 10ppm # limit - their status should be ‘Red’. However, if the range of the sensor is 0-10ppm, then the command center - # would actually see their status as *Green* (not Red or even Yellow) with a 5.5ppm per hour average - seemingly - # well under the limit. Why? Because the sensor would have provided [30mins at 1ppm. Then 30mins at 10ppm] which - # averages to 5.5ppm. For time-weighted average math to give reliable results, the sensor must have a much - # larger range than the limits - 2x being a minimum. If the limit is set at or near the sensor range, a - # firefighter's status would essentially never go red, even if they were well over the limit. + # would actually see their status as *Range Exceeded* (not Red, Yellow or Green), which is not very helpful. + # It's essentially saying "this firefighter's average exposure is unknown - it may be OK or it may not. + # Prometeo can't tell, because the sensors aren't sensitive enough for these conditions". For the firefighter + # to get an accurate report, this sensor would need to have a range of at least 25ppm (and likely more), + # so that exposure could be accurately measured and averaged to 13ppm. + # (Note: the sensor returns *Range Exceeded* to prevent incorrect PPM averages from being calculated. + # e.g. in the above scenario, we do not want to incorrectly calculate an average of 5.5ppm (Green) from a + # sensor showing 30mins at 1ppm and 30mins at 10ppm, the max the sensor can 'see'). for gas in self.SUPPORTED_GASES : limits = [window[GAS_LIMITS_PROPERTY][gas] for window in self.WINDOWS_AND_LIMITS] - if ( (min(limits) < SENSOR_RANGE_PPM[gas]['min']) or ((max(limits)*2) > SENSOR_RANGE_PPM[gas]['max']) ) : + if ( (min(limits) < SENSOR_RANGE_PPM[gas]['min']) or (max(limits) > SENSOR_RANGE_PPM[gas]['max']) ) : valid_config = False - message = ("%s : One or more of the '%s' configurations %s is incompatible with the range of the '%s' sensor (min: %s, max: %s)." + - "\nPlease note that sensors must have a much larger range than the limits - 2x being a minimum.") \ + message = ("%s : One or more of the '%s' configurations %s is incompatible with the range of the '%s' sensor (min: %s, max: %s).") \ % (config_filename, GAS_LIMITS_PROPERTY, limits, gas, SENSOR_RANGE_PPM[gas]['min'], SENSOR_RANGE_PPM[gas]['max']) self.logger.critical(message) critical_config_issues += [message] + if ((max(limits)*2) > SENSOR_RANGE_PPM[gas]['max']) : + # This is valid, but not optimal. Produce a warning. + message = ("%s : One or more of the '%s' configurations %s is very close to the range of the '%s' sensor (min: %s, max: %s)." + + "\nSensors shoud have a much larger range than the limits - e.g. 2x at a minimum .") \ + % (config_filename, GAS_LIMITS_PROPERTY, limits, gas, SENSOR_RANGE_PPM[gas]['min'], SENSOR_RANGE_PPM[gas]['max']) + self.logger.warning(message) # Check there's a valid definition of yellow - should be a percentage between 1 and 99 if not ( (self.YELLOW_WARNING_PERCENT > 0) and (self.YELLOW_WARNING_PERCENT < 100) ) : @@ -319,7 +328,7 @@ def _calculate_TWA_and_gauge_for_all_firefighters(self, sensor_log_chunk_df, ff_ # It's essential to know when a sensor value can't be trusted - i.e. when it has exceeded its range (signalled # by the value '-1'). When this happens, we need to replace that sensor's value with something that - # both 1. identifies it as untrustworthy and 2. also causes calculated values like TWAs and Gauges to be + # both (A) identifies it as untrustworthy and (B) also causes calculated values like TWAs and Gauges to be # similarly identified. That value is infinity (np.inf). To to illustrate why: Say a firefighter experiences # [30mins at 1ppm. Then 30mins at 25ppm] and the 1 hour limit is 10ppm. Then 1 hour into the fire, this # firefighter has experienced an average of 13ppm per hour, well over the 10ppm limit - their status should be