Hi Han Bin, Please take a look at the log from one of the tests. This code is printed from void addNewEntry(TimeSyncMsg *msg) function. As you can see, every time the number of the table entries (numEntries) is >= 4, the timeError of new TimeSync message is checked, and it never fits between the limits of ENTRY_THROWOUT_LIMIT (500).
The logs are from experiment with 2 motes, each within a distance of ~4 inches from each other. msg->localTime:657714 msg->globalTime:750209 timeError:-92495 offsetAverage:0 localAverage:0 msg->localTime:767248 msg->globalTime:767367 timeError:92376 offsetAverage:92495 localAverage:657714 msg->localTime:876782 msg->globalTime:876903 timeError:90192 offsetAverage:46307 localAverage:712481 msg->localTime:986316 msg->globalTime:986439 timeError:-283317 offsetAverage:30912 localAverage:767249 msg->localTime:1095850 msg->globalTime:1095975 timeError:-99916 offsetAverage:23215 localAverage:822017 timeError too big msg->localTime:1205384 msg->globalTime:1205511 timeError:-149120 offsetAverage:23215 localAverage:822017 timeError too big msg->localTime:1314918 msg->globalTime:1315047 timeError:-198325 offsetAverage:23215 localAverage:822017 timeError too big msg->localTime:1424452 msg->globalTime:1424583 timeError:-247530 offsetAverage:23215 localAverage:822017 timeError too big - cleanTable msg->localTime:1533986 msg->globalTime:1534119 timeError:-296735 offsetAverage:23215 localAverage:822017 msg->localTime:1643520 msg->globalTime:1643655 timeError:-49204 offsetAverage:133 localAverage:1533986 msg->localTime:1753055 msg->globalTime:1753191 timeError:197128 offsetAverage:134 localAverage:1588753 msg->localTime:1862589 msg->globalTime:1862727 timeError:-7293 offsetAverage:135 localAverage:1643522 msg->localTime:1972123 msg->globalTime:1972263 timeError:-1510611 offsetAverage:136 localAverage:1698290 timeError too big msg->localTime:2081657 msg->globalTime:2081799 timeError:-2114860 offsetAverage:136 localAverage:1698290 timeError too big msg->localTime:2191191 msg->globalTime:2191335 timeError:-2719110 offsetAverage:136 localAverage:1698290 timeError too big msg->localTime:2300725 msg->globalTime:2300871 timeError:-3323359 offsetAverage:136 localAverage:1698290 timeError too big - cleanTable msg->localTime:2410259 msg->globalTime:2410407 timeError:-3927609 offsetAverage:136 localAverage:1698290 Best, Marcin On Tue, Sep 25, 2012 at 4:28 AM, LoveYou <[email protected]> wrote: > Dear Marcin, > > Your explanation help me understood more how FTSP implementation works. > Thank your about this. As your explanation, at the receiver, we get two > time values: > msg->globalTime = time_at_sender_when_sender_sent (Call > TimeSyncAMSend.send) > msg->localTime = time_at_receiver_when_sender_sent (by calling > TimeSyncPacket.eventTime(msg)) > so we get timeOffset = msg->globalTime - msg->localTime; > And we expect that timeOffset does not vary much for each packet. However, > I observed that the timeOffset value is very abnormal, it changes time to > time. Moreover, value of msg->localTime does not correspond to the time of > the event in receiver's local clock (I get receiver's local clock by > calling GlobalTime.getLocalTime() to compare with). That is the reason why > we get the large timeError value in addNewEntry function > > timeError = msg->localTime; > call GlobalTime.local2Global((uint32_t*)(&timeError)); > timeError -= msg->globalTime; > > I'm trying to test many time but FTSP can't work. How about your result? > Could you print out the log file including the msg->localTime, > msg->globalTime, timeError, etc for comparasion? > Thank you very much! > > Best regards, > Han Bin > > >
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