I am looking for a function which is equivalence to iVolume in MT4.
Does Zorro have it?

Forex has no volume. That's for stocks only.

You could theoretically use the quote frequency instead, but this is not usable for trade signals because it depends on the broker, not on the market.

So how can I use quote frequency?

Not easily. It is available in the asset struct through the "nCounter" element. But you had to write a C function for accessing it - that's not for beginners.

We could implement it of course, but we would need a good reason for that, as the quote frequency is mostly random and not a measure of the trade volume.

This tick bot is very interesting.
What do you think?

http://cyberbot2.com/
http://www.myfxbook.com/members/CyberFXorg/cyberbot2/425543

Just to be clear here, Forex does have volume - it's called tick volume and differs from order volume as seen on Futures and stocks. Tick Volume might seem useless but it actually has almost the same predictive properties as Order Volume, if used right of course. Since the data is available there should be a function for it.

I think Forex can not have a volume, because for Forex there is no global exchange that can register trades and sum up the volume.

The tick volume is not a volume, its the frequency of quotes of your broker. I think no broker publishes his volume. When the broker generates many price quotes the frequency goes up, so one could think it is something similar to the trade volume, but its only similar to the price volatility and not to the volume. Forex trades by retail brokers are anyway very small compared to the total forex market, so the quote frequency of a broker has no relation to the forex trade volume and I doubt it can predict anything.

The tick volume is not really similar to the price volatility, as it normally only counts the price changes, but not the price range. You could maybe say that it is similar to the noise of the volatility.

In any case it depends on how the broker counts price changes - 4 or 5 digits - and which liquidity providers are used. So it does not reflect the market, like price or volume, but the traffic on the broker's server. It's hard to see how that could be used for a trade system.

the only usefull stats i know is to follow the fx futures

http://www.cmegroup.com/trading/fx/

it could be very usefull to have it embedded into Zorro.

Forex Broker Volume Comparison
http://www.myfxbook.com/forex-broker-volume