Trying to test FTVS with PLC attached to laptop, not working

[JZerb]

The bit identifier within a word of the RSLogix 500 SLC/MicroLogix platform uses "/" rather than "."

Make you Online browsed Connection {::[ML1200]I0:0/1} for Bit 1 of the Word 0 of file I0.

I did this and it still didnt work, but after reading what was said below about using registers to address bits instead of trying to feed into the I/O directly everything works great now! thank you. but now the question is why was the bit tags in the Tag Browser window were showing up in the Online folder incorrectly? i didnt have the option to select a B3:0/1 tag directly, i had to select the B3:0 tag in the Tag Browser then go and manually add the /1 so it was looking at the correct bit in the word. if i went into the PLC folder that i created and in the Tag Browser and selected the tag that i wanted it worked fine. why would one use one folder or the other? the Online folder in the ML1200 folder tree versus the PLC folder? thanks again to all, this place has been a big help when i post only after trying diligently to figure things out on my own.

You've probably got everything right. Your HMI (or at least, your PC pretending to be a HMI) is probably sending a message to the PLC to say "turn on I:0/1", and your PLC is doing exactly as it is asked.

Then, about 0.01seconds later, your PLC is reading the status of I:0/1 from the actual onboard input terminal, finding that it's off, and updating the register in the PLC to indicate as such.

tl;dr, never, ever address physical I/O directly from a HMI. Use N or B registers, and map from there in the PLC code.

 

[Jsu0234m]

You can't tie the value of a PB on the HMI directly to an input on the PLC.(You can but it won't actually toggle the input on or off) You can tie the indicator of a PB to the input on a PLC.

This is along the same lines as not being able to toggle on/off an actual input or output tag in the PLC, you can force them but you can't toggle them.