How does per diem scheduling work in a hospital?

At the facility I work at, per diem employees submit a monthly sheet telling what days and times they can work for the month and then are called in only if needed during those times....Is this also how a hospital does their per diem shifts as well? I would like to get a second job at a hospital but would not want it to interfere with the job I have now. How does per diem work in a hospital exactly?
It may depend on the facility. In my experience at a particular facility, Per Diem Staff have a minimum commitment of 4 shifts every 4-weeks or 2 pay periods. 2 of the shifts must be weekend shifts. Of course, you can do more as you are able. The Per Diem staff turns in dates of availability weeks ahead of the final schedule and are granted shifts based on unit needs. Per Diem Staff gets cancelled first when the census is low. Per Diem Staff are either Med-Surg Pool, ER, or ICU Pool. They are not under the unit management, rather, they are under the Nursing Pool Unit Manager.

Our facility is a lot like Juan de la Cruz's. There is a minimum commitment. Of course, peope get sick so we might call that per diem nurse between times and they are welcome to contact the House Supervisor to add hours if they like. Saves us from paying agency.

Where I work there is no minimum commitment and no availability given. Each floor has their own list of casuals and some people are on more than one list.

My workplace requires PRN/per-diem employees to work at least once in a 30-day schedule to avoid being auto-terminated. I send an email to the scheduler or leave her a voice mail with my availability for the next month, and they schedule me appropriately.

It depends on the facility. I worked per diem when I was an aide and I would give my availability to the scheduler and she would put me on days I was needed that fit with my availability. When I worked as a nurse in the hospital, everyone filled out a scheduling spreadsheet by a certain date. Per diems filled out what shifts they were available. They could not just be placed on shifts that they didn't sign themselves up for (like the rest of us could) and they had no minimum shift requirement. If there were enough permanent staff on the shifts they signed up for, they did not get hours. When I first starting working there we had "unit based per diems" who were assigned specifically to one unit but the hospital did away with them years ago. Per diems were always the first canceled when census was low.