The CPM1A-10 and CPM1A-20 units are NOT expandable. You must use a -30 or -40 to have expansion capability. All CPM2A cpu's can be expanded.
The CPM1A-MAD01 has two analog inputs and one analog output. Be careful, this unit only offers 8 bit resolution (0-255 decimal). The CPM1A-MAD11, also two analog in and one analog output offers 0-6000 decimal resolution.
Hope this helps.