fx2n-48mr problem

[hatemmorsy]

dears i need your help 

i have plc fx2n-48mr connect with two fx2n-80mt  its manage dancing fountain  

its was working very good but i had problem form some time now the fx2n-48mr stop for 1 sec or 2 and work back this happen many times in our fountain show 

i this 1 sec or 2 sec the led of prog E is flash 

is this the battery problem  

im not  familiar in plc so can some one help me in this and i can answer any Question if need