Thanks to everyone for your help.

Is a thermostat, TSTAT and RM TH all the same thing?

If a properly running systems run for long periods of time, doesn't
that translate to high energy bills? What would be a reasonable ratio
of on to off time?

I didn't want to take much of anyone's time, but I guess I should
disclose that my system is not running right. It was installed in a
new house four years ago. I've had to have the system recharged 3
times, the last time a few weeks ago. The previous two times fixed the
short cycling, but not this time.

The AC company found a leak in my evaporator coil. I guess it needs to
be fixed, but it's going to be expensive. I was hoping that the
recharging would buy me some time, but i guess the leak has gotten too
big.

Lastly, when they found the problem, the guy did not reseal the
evaporator coil housing access panel. I just went up in the attic and
noticed there is some cold air coming out. I guess i will get up there
with duct tape, but I can't imagine it having that big an effect.
There is also air coming out of my drain pipe (because there is no cap
on it). I guess I will put some tape on that too.

Thanks everyone.