What exactly do you want help with ?
FactoryTalk View ME Alarming uses "trigger" tags which are typically addressed to one or more words of a PLC data table.
the data file starts at bit b50/17 and is 400 bits long
In Allen-Bradley nomenclature, Binary and Integer data file syntax is
Bxx:yy/zz
Where the data type is B for Binary and N for Integer
xx = Data File number
yy = 16-bit Word number of the data file in decimal
zz = Bit number of each Word, in decimal
With the PLC-5 and SLC-500, you can be a little informal with words and bits, which I don't like because it's confusing. I would have to experiment to be sure that FactoryTalk View ME accepts the informal omission of the Word number, and lets you start a bit array anywhere.
"B50/17" might really be "B50:17" which would start the data array at the 18th word of data file B50.
Or it might really be "B50/17", where each word has 16 bits starting at zero. That would mean "B50/17" is equivalent to "B50:01/01".
To make things a little more confusing, PLC-5 I/O data tables are addressed in octal, while PLC-5 internal data memory is addressed in decimal. So "bit 17" in an Input data table is different from "bit 17" in an Integer or Binary data table.
All this is unnecessary diversion until we know what you actual question and configuration are. Detailed descriptions and even screenshots would be great.
So post the exact and complete Alarm Trigger configuration address.