# Sequence/sleep

**URL:** <https://forum.certara.com/t/sequence-sleep/2441>\
**Category:** Modelling and Simulation\
**Created:** [June 28, 2012, 11:54pm UTC](https://forum.certara.com/t/sequence-sleep/2441 "2012-06-28T23:54:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kyang12](https://avatars.discourse-cdn.com/v4/letter/k/a87d85/32.png) [@kyang12](https://forum.certara.com/u/kyang12)\
**Post date:** [June 28, 2012, 11:54pm UTC](https://forum.certara.com/t/sequence-sleep/2441/1 "2012-06-28T23:54:31Z")

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Hi, I was trying to use sequence/sleep function, but got the warning message saying “variable ‘sequence’ undefined”. I would like to turn on wash between 20 - 21 min. Could you help with this problem? My code is as follows; test(){ #Diff Eqs deriv(AM = - CM \* (PSinf + Wash) + (CC \* PSeff) + (AB \* Kleak)); deriv(AC = (PSinf \* CM)- (CC \* PSeff)- (CLbil \* CC)) deriv(AB = (CLbil \* CC)- (AB \* Kleak)) #Dose dosepoint(AM, idosevar = AMDose, infdosevar = AMInfDose, infratevar = AMInfRate) #Variables CM = AM / VM CC = AC / VC ACB = AC + AB VM = 1500 VC = 6.83 Sequence{ Wash = 0; sleep(20); Wash = 10000; sleep(21); Wash = 0; } #Observation error(CMEps = 1) observe(CMObs = CM \* (1 + CMEps)) error(ACBEps = 1) observe(ACBObs = ACB \* (1 + ACBEps)) #Parameters stparm(PSinf = tvPSinf) stparm(PSeff = tvPSeff) stparm(CLbil = tvCLbil) stparm(Kleak = tvKleak) #Initial fixef(tvPSinf = c(, 1, )) fixef(tvPSeff = c(, 1, )) fixef(tvCLbil = c(, 1, )) fixef(tvKleak = c(, 1, )) } Thanks, Kyunghee

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**Author:** ![SimonDavis](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@SimonDavis](https://forum.certara.com/u/SimonDavis)\
**Post date:** [June 29, 2012, 6:54am UTC](https://forum.certara.com/t/sequence-sleep/2441/2 "2012-06-29T06:54:03Z")

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Kyunghee, Sequence should start with lowercase ‘s’. however you will still need to define the variable Wash Simon