@belgacom Hello Armaud,
using multiple REXLANG blocks in one task should generally not be a problem. However, it depends on how computationally intensive the programs in the REXLANG blocks are. Please try to set a longer task period and look at Diagnostics in the watch mode. I am mainly talking about time statistics. Check the:
Target -> Diagnostics -> task name -> Task -> Enable
We are especially interested in max time and average time. Please note that times are in milliseconds.
Cheers,
Jan