zaico 

I understand, but the thing is I can only access to that time through backtesting because it's a demo account. Anyway I'll try If there's a time frame I can access with the current contract data. Can you give some clue on how to use non-time bars. I've read something but I don't get anything clear. thanks agains

In a nutshell,

Time-based bars
Print a fixed amount of bars every x period. E.g. there's always 12 5-mins bars in 1 hour period.

Non-time-based bars
Print a variable amount of bars in a given period. The variable amount depends on the nature of the bar.

There's probably some documentation on the Wiki on NexusFi but for expediency you can check this for reference

https://help.cqg.com/cqgic/14/default.htm#!Documents/constantvolumebarcvb1.htm

https://help.cqg.com/cqgic/default.htm#!Documents/renkorenko.htm

https://help.cqg.com/cqgic/default.htm#!Documents/rangebarrb.htm

Thanks again for your help! I'll have a look as soon as I can