HP ProCurve Management And Configuration Manual page 214

Time Protocols
TimeP: Viewing, Selecting, and Configuring
Figure 9-17. Example of Configuring Timep for Manual Operation
9-22
Changing the TimeP Poll Interval. This command lets you specify how
long the switch waits between time polling intervals. The default is 720
minutes and the range is 1 to 9999 minutes. (This parameter is separate from
the poll interval parameter used for SNTP operation.)
Syntax: ip timep < dhcp | manual > interval < 1 - 9999 >
For example, to change the poll interval to 60 minutes:
ProCurve(config)# ip timep interval 60