Why, when I am signed it to google, but when I try to access or save anything on my Google calendar, it says I have been logged out?

How to set up Google mail, calendars, and contacts on iPhone or iPad
Open Settings.
Tap Passwords & Accounts.
Tap Add Account.
Tap Google.
Enter your Google account credentials.
Make sure the switches for mail, contacts, and calendars are in the 'on' or 'off' positions depending on where you want them.
Tap Save.

Try checking this link for this concern http://www.google.com/support/calendar/bin/answer.py?hl=en&answer=99358 , you can find there the steps to setup the Google calendar..

Hope that helps.........

We often get asked by customers and prospects about Google Calendar and their ability to use it in a HIPAA compliant manner. We know the HIPAA market is vast so we can empathize with just how many people need to use cloud-based storage services in this sector.
Google Calendar is a time-management and scheduling calendar service developed by Google. It was first released in 2006.
According to Google's own HIPAA compliance guidelines, businesses that want to store PHI on Google Drive in a HIPAA-compliant way need to sign a Business Associate Agreement with Google. The good news is that Google offers BAAs for paid users of its Google Apps platform. Specifically, the BAA covers Gmail, Google Calendar, Google Drive, and Google Apps Vault. The big caveat, though, is that it's incumbent on the health care organization itself to configure those services to be HIPAA Compliant. The BAA also requires that you disable all additional services in the Admin console.
The Business Associate Agreement is a key component to HIPAA compliance between a Covered Entity and a Business Associate. Since Google offers one that covers Google Calendar, we conclude that Google Calendar is a HIPAA compliant service. It's important to note however, you must sign a BAA with Google to be HIPAA compliant.

Hi
The only reason I can think of for your iPad not signing into Google when your Mac can is that the credentials being entered are not the same in both cases. The username should be the same as this is easily checked at each machine when you are on the log in page. The password is different as it is usually only shown on any screen as dots or asterisks. If you have saved the details on each machine then I would suggest that you check the usernames are the same and then change your account password using the Mac and the instructions below.
Log in to your Gmail account, click on the cogwheel to the top right of the window, and click "Settings" Click on the Accounts and Import tab and the password options, including changing the password are the first options on the list.
Having changed the password you can log in again from the Mac and then try logging in on the iPad using the new password.
Hope this is helpful, if so would you please register that with Fixya
Cheers

I believe you're already logged into your Google Account in Google Chrome which keeps your logged-in status. Google will use your login credentials for Google Chrome to allow you to access your Gmail without requiring you to login again. To force a login each time, you may wish to logout of your Google Account from Google Chrome.

Can you go to "http://calendar.google.com"?

Do you get an error?

open the hosts file with notepad
If there is anything under the "127.0.0.1 localhost"
delete it and then save the file. (don't delete 127.0.0.1 localhost)
restart the computer and try again

Maybe you access your acc on another machine, that why is ask for.
So try this:
You may not want to sign out each time when using your own PC, but it is particularly important to sign out if you are accessing your account on a shared computer or public network. However, if you forget to log out, you can log out of all previous sessions the next time you are at a computer.
To do this, open your Gmail or Google Apps account and click on the Details link in the bottom right of your screen. This will open up a pop up window where you can see recent activity, whether your Gmail or Google Apps account is open in any other location, and choose to Sign out of all other sessions. Clicking that button will ensure all your previous Gmail and Google Apps sessions are logged out, leaving you logged in to the current computer only.

had the problem on old computer...turned out to be date/time stamp. resetting date/time solved the problem. also had the issue pop up on new laptop w/ windows 7 ie. turned out to be in tools...internet options...trusted sites...sites. somehow i had added gmail.google.com to trusted sites and gmail was looping between http and https. removed the entry and problem disappeared.