Allen bradley Micrologix Read Request for bool from Data File B.

Hi all,

Working scenario is, My HMI project is having two integer tags at address N7:0 and N7:1. In this case i know i can make only one read request to PLC and ask for both tags by asking for returning the 4 bytes of memory starting from address 0.

Is it possible to do above thing in following cases.
1) If integers belong to file format B. Can it also be done in one read request?
2) If BOOL is belongs to file format N or B. i.e is it possible to make only one single request to read two bool tags(two bits) from N or B file type.?

Please help me in this regard.

hi Viti,

What HMI are you using?

I don't use many HMI panels, most of our HMI work is done on a PC running WonderWare Intouch. I know that the DASABCIP I/O driver from wonderware definitely does optimise reads, so what I normally do is try to make sure that most of my data is sequential, i.e. my integers might be from N9:0 to N9:64, my bools from N9:128 to N9:132 leaving a bit of space after each address block for later expansion. I normally avoid floating point if I can, at least in Micrologix processors.

However, I personally don't have any applications that put such a huge strain on the PLC that I normally worry about it too much! I have applications reading from the N9 file, the B3 file and a couple of floating point numbers too without any problems.