On 11 September 1862, Col Gregory complained about the laxness of the guards. [general order 49, 91st PA, 11 September 1862]
On 13 August 1863, the regiment was slow in posting the guard, because, as Sinex explained, they did not hear the signal. [letter, Sinex to Marvin]
On 15 January 1865 orders were issued prescribing how sentinels were to salute officers
Also see various schedules.