You all are welcome
The expert can be attached to more than one instrument. For example if you want to log EURUSD, GBPUSD, GBPCHF spreads at the same time, then you must attach the expert to EURUSD, GBPUSD, GBPCHF graphs. Expert will create files for all three currency pairs. For EURUSD it will create EURUSD.csv, for GBPUSD it will create GBPUSD.csv, .... .
One more thing. There is some mystical space in line
if(FileSeek(out,0,SEEK_END)) FileWrite(out,Day(),Month(),Hour(),Minute(),Second s(),CurrentSpread);
Please replace Second s() with Seconds()