# 868LP: workings of Auto Early Wake-Up Sleep Option

**URL:** <https://forums.digi.com/t/868lp-workings-of-auto-early-wake-up-sleep-option/13717>\
**Category:** XBee - DigiMesh\
**Tags:** sleep, battery, 868lp, digimesh, xbee\
**Created:** [October 9, 2014, 6:58am UTC](https://forums.digi.com/t/868lp-workings-of-auto-early-wake-up-sleep-option/13717 "2014-10-09T06:58:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![DigiMarty](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@DigiMarty](https://forums.digi.com/u/DigiMarty)\
**Post date:** [October 9, 2014, 6:58am UTC](https://forums.digi.com/t/868lp-workings-of-auto-early-wake-up-sleep-option/13717/1 "2014-10-09T06:58:42Z")

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Situation: a battery powered 868LP DigiMesh network in synchronous cyclic sleep mode with Auto Early Wake-Up Sleep Option enabled.

When a RF module has lost sync, how long exactly will the time period be between the early wake up moment and the moment the module normally wakes up?

We need this information to get an indication of the battery life time of our application.

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<div class="post-metadata">

**Author:** ![mvut](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.digi.com/mvut/32/31_2.png) [@mvut](https://forums.digi.com/u/mvut)\
**Post date:** [October 9, 2014, 11:16am UTC](https://forums.digi.com/t/868lp-workings-of-auto-early-wake-up-sleep-option/13717/2 "2014-10-09T11:16:31Z")

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If enabled in the firmware, for each missed sync message, a Digi Mesh module will wale up about 10mS earlier.

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<div class="post-metadata">

**Author:** ![DigiMarty](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@DigiMarty](https://forums.digi.com/u/DigiMarty)\
**Post date:** [October 14, 2014, 4:46am UTC](https://forums.digi.com/t/868lp-workings-of-auto-early-wake-up-sleep-option/13717/3 "2014-10-14T04:46:49Z")

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Thanks, that’s the answer I was looking for. 🙂