For example, I want to have an RSI (period 2) <= 20, within the past 5 days.

I wrote "MIN(WRSI2,5) <= 20" but I'm getting a "Formula Error." 

Thanks for your help.

If it is a plain RSI without Wilder's smoothing then you could write the following.

MIN(RSI2,5) <= 20

The Condition Formula would be quite a bit longer for the Wilder's RSI version with Wilder's smoothing however because we can't use the MIN() function and because the formula for the RSI itself is quite a bit longer.

50 * (C - XAVGC3.1) / 2 / (.50003052 * (ABS(C - C1) + .5 * (ABS(C1 - C2) + .5 * (ABS(C2 - C3) + .5 * (ABS(C3 - C4) + .5 * (ABS(C4 - C5) + .5 * (ABS(C5 - C6) + .5 * (ABS(C6 - C7) + .5 * (ABS(C7 - C8) + .5 * (ABS(C8 - C9) + .5 * (ABS(C9 - C10) + .5 * (ABS(C10 - C11) + .5 * (ABS(C11 - C12) + .5 * (ABS(C12 - C13) + .5 * (ABS(C13 - C14)))))))))))))))) + 50 <= 20 OR 50 * (C1 - XAVGC3.2) / 2 / (.50003052 * (ABS(C1 - C2) + .5 * (ABS(C2 - C3) + .5 * (ABS(C3 - C4) + .5 * (ABS(C4 - C5) + .5 * (ABS(C5 - C6) + .5 * (ABS(C6 - C7) + .5 * (ABS(C7 - C8) + .5 * (ABS(C8 - C9) + .5 * (ABS(C9 - C10) + .5 * (ABS(C10 - C11) + .5 * (ABS(C11 - C12) + .5 * (ABS(C12 - C13) + .5 * (ABS(C13 - C14) + .5 * (ABS(C14 - C15)))))))))))))))) + 50 <= 20 OR 50 * (C2 - XAVGC3.3) / 2 / (.50003052 * (ABS(C2 - C3) + .5 * (ABS(C3 - C4) + .5 * (ABS(C4 - C5) + .5 * (ABS(C5 - C6) + .5 * (ABS(C6 - C7) + .5 * (ABS(C7 - C8) + .5 * (ABS(C8 - C9) + .5 * (ABS(C9 - C10) + .5 * (ABS(C10 - C11) + .5 * (ABS(C11 - C12) + .5 * (ABS(C12 - C13) + .5 * (ABS(C13 - C14) + .5 * (ABS(C14 - C15) + .5 * (ABS(C15 - C16)))))))))))))))) + 50 <= 20 OR 50 * (C3 - XAVGC3.4) / 2 / (.50003052 * (ABS(C3 - C4) + .5 * (ABS(C4 - C5) + .5 * (ABS(C5 - C6) + .5 * (ABS(C6 - C7) + .5 * (ABS(C7 - C8) + .5 * (ABS(C8 - C9) + .5 * (ABS(C9 - C10) + .5 * (ABS(C10 - C11) + .5 * (ABS(C11 - C12) + .5 * (ABS(C12 - C13) + .5 * (ABS(C13 - C14) + .5 * (ABS(C14 - C15) + .5 * (ABS(C15 - C16) + .5 * (ABS(C16 - C17)))))))))))))))) + 50 <= 20 OR 50 * (C4 - XAVGC3.5) / 2 / (.50003052 * (ABS(C4 - C5) + .5 * (ABS(C5 - C6) + .5 * (ABS(C6 - C7) + .5 * (ABS(C7 - C8) + .5 * (ABS(C8 - C9) + .5 * (ABS(C9 - C10) + .5 * (ABS(C10 - C11) + .5 * (ABS(C11 - C12) + .5 * (ABS(C12 - C13) + .5 * (ABS(C13 - C14) + .5 * (ABS(C14 - C15) + .5 * (ABS(C15 - C16) + .5 * (ABS(C16 - C17) + .5 * (ABS(C17 - C18)))))))))))))))) + 50 <= 20

You could use the following shorter Boolean Formula with the technique given below however.

Condition True at Least Once Over x Bars

50 * (C - XAVGC3.1) / 2 / (.50003052 * (ABS(C - C1) + .5 * (ABS(C1 - C2) + .5 * (ABS(C2 - C3) + .5 * (ABS(C3 - C4) + .5 * (ABS(C4 - C5) + .5 * (ABS(C5 - C6) + .5 * (ABS(C6 - C7) + .5 * (ABS(C7 - C8) + .5 * (ABS(C8 - C9) + .5 * (ABS(C9 - C10) + .5 * (ABS(C10 - C11) + .5 * (ABS(C11 - C12) + .5 * (ABS(C12 - C13) + .5 * (ABS(C13 - C14)))))))))))))))) + 50 <= 20

OMG, I'm so glad I asked, b/c I'd never have figured it out on my own.  Thank you so much!

You're welcome.