Sporadic Minor Alarms for Altitude Sensor
ICSeverity
5 - Notice
Impact
Self-recovery, no service impact.
Description
The device may report envmon minor "ALTITUDE Sensor: Invalid sensor read error" sporadically. This is not due to faulty hardware, and a replacement is not required when your issue matches: there are minor envmon alarms show up in syslogs and show alarms; and physically on the router the Alarm Amber LED will blink during these minor errors. A sensor measures air pressure used to calculate an altitude value, and the software threshold for the altitude value raises an alarm if the read altitude is less than -60 meters. The altitude sensor has a tolerance of +/- 200 meters which meets the system requirement for fan algorithm but means that altitude alarms can possibly happen on low-altitude router installations around -60 to 140 meters, where the sensor can read below -60 meters due to its wide tolerances. The list of affected PIDs within the NCS540 Product Family can be reviewed under the Release Notes for Cisco bug ID CSCwe74645.
SyslogMessage
PKT_INFRA-FM-4-FAULT_MINOR
MessageSample
2022 Dec 16 17:51:17.866 <<ipaddress>> %PKT_INFRA-FM-4-FAULT_MINOR : ALARM_MINOR :Invalid sensor read error :DECLARE :0/RP0/CPU0:
MB-ALTITUDE Sensor has raised an alarm for Invalid Sensor read error THIS IS A SAMPLE MESSAGE
ProductFamily
Cisco Network Convergence System 540 Series Routers
Regex
N/A
Recommendation
To verify this problem, first look at the output of show environment altitude . The altitude value is -32768 once the alarm sets. You can see the problem bounce between set (declare) and clear. This error can be ignored in this circumstance.
Commands
#show platform
#show install active summary
#show logging 500
#show alarms brief
#show environment altitude
#show environment
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