mrp is nothing but material requirement planning,mps means 
master production sheduler.in mrp we can plan all the 
material with final assembly also while mrp run we can get 
the procurement proposals for all the material including 
final assembly, in mps planning we can get the proposal 
those who are marked as a mps material.(material master it 
self we say it)

MPS :- Master Production scheduling is generally done for 
when the product groups exists. By doing MPS we basically 
disagreegate the group requirements into individual product 
requirements. By doing MPS we can disagreegate the plan and 
we can only creat planned order for finished products.

MRP :- Materials requirment planning is done to drill down 
for individual product once the planned orders for finished 
products are created by MPS. However, we can use only MRP 
for any individual material anytime.

mps is done for fg.mrp for row material sfg and fg.
mps time fense can be fixed.we can avoid auto po and auto 
issue of materials in mps.

MRP-Material Requirement planning.It is used for multi 
lelvel planning.But MPS is used for critical level or 
single level planning.planning time fence is must for mps

In The MPS, the comapny level critical components are 
planned and in the mterial master, the MRP type is choosen 
accordingly, this is generally done for single level. This 
is planned seperately and this can be also done using 
interactive planning.

In MRP or time phased planning, the BOm is exploded and 
netting is done and component level quantity and time 
requirements are planned.

Fisrt MPS is done, then MRP is run.

MPS is for Final products basically planned by the Top 
management for costly items with extra care. MPS can be 
planned MRP materials also.
Where as MRP starts after the MSP materials decides. MRP 
can plan all the materials for the Final product decided by 
MPS