2651A Control Error

I have a problem with conrtoll my 2651A.
When i use same code to program 2651A as a power source but cause DUT error when current is above 5A.
Please help me to solve the problem. In addition I = 20A works only device is disconnected

\----------------------------------------
smua.reset() \n
smua.source.output = smua.OUTPUT_ON \n
smua.source.limitp = 200 \n
smua.sense = smua.SENSE_REMOTE \n
smua.source.levelv = %1 \n
smua.source.limiti = %1 \n
v = smua.measure.v() \n
print(v) \n
\------------------------------------------
%1 refers to C++ argument which is V = 10 and I = 5 or I = 20
 

Try setting the source level and source limits before turning the output on.

Keep in mind, when using power limit, the current limit in use will be the lower of the limit.i value or the computed value from source v and requested power limit (watts).

If troubles persist, can you tell us more about the DUT error and the only if device disconnected observations.
Is device accepting power from SMU or is SMU sinking power from DUT?