Desperate help needed programming a register on GX-Developer

[treenifer]

Hey guys,

I'm taking a course on PLCs for my BTEC and my teacher is shockingly incompetant to the point the he took 2 hours to work out how to put in an input on GX-Developer... with our assistance... sigh

Needless to say, I'm desperate for help with an assignment on ladder logic. I'm not going to ask that you guys give me all the answers, but basically we've been given this:

|--| |------(R1)15---|
| IP0
|--| |-------[BSR]---|
| IP1 [R1 ]
| [BIT]
| [F1]

And told "rung 1 shows contact IP0 connected to a register. You must specify the bit to change when IP0 is closed. In this case, bit 15 which is the MSB. If IP0 is closed bit 15 is high, if open it is low. Rung 2 shows 1P1 followed by a command BSR (Bit Shift Right). Every time IP1 is closed, all the bits are shifted right. The LSB falls off the end and the MSB is replaced by a 1 or 0 depending on the state of IP0. Each time a right shift is done with bit 15 being replaced by a 0, the binary number is divided by two. If BSL is used (Bit Shift Left), all the bits are shifted left, with the LSB being replaced by a zerp, the binary value is doubled. Create the above programme using GX-DEveloper and text it under simulation"

...This is like French to me. I've never worked on PLCs before and I've asked him to explain but he's so bad he can't. I'm not going to ask you to do this assignment (I actually want to learn!) but could I have some sort of starting point? I am so clueless as to how even to approach this - how do you define the register? Indicate bit 15? I'm so lost!

Thank you so much anyone who sees this :/

 

[Sergei Troizky]

This is not an assignment for one who "never worked on PLCs before" and does not know how to define a register or indicate a bit.
What PLC model?

 

[treenifer]

This is not an assignment for one who "never 'worked on PLCs before" and does not know how to define a register or indicate a bit.
What PLC model?

I'm not surprised I got that as an answer. The teacher is utterly hopeless and has no idea what he's doing - I would bet money that he's downloaded this question from somewhere. I've already given him stick about the fact our assignment specifically asked for us to program an Up-Down counter, yet he cannot program an Up-Down counter himself.

In regards to the PLC question, the FX-series 3U. However, the only reason any of us use that one in the class is because it's the only one that seems to work on the (garbled, possibly illegal) copies of GX-Developer that he's given us. He told us to use the FX series because "it has enough inputs and outputs for us", and since the BTEC never actually requires us to use a PLC, just form the ladder logic programs, help on any of the PLCs that GX-Developer has would be so welcome.

 

[Lancie1]

Treenifer, your instructions are not clear, but this is the best interpretation that I can make. Of course, this program is fairlly useless without some more instructions about what it is supposed to do.

PS: There is a free (not illegal) copy of the Mitsubishi MELSOFT GX Developer program that you can download from the Mitsubishi Electric Corporation at this link:
http://www.mitsubishi-automation.com/products/software_gx_developer_content.htm?distributor=0

 

[Lancie1]

Help on any of the PLCs that GX-Developer has would be so welcome.

As for the specific Mitsubishi PLC model, you may change the type in GX Developer by clicking "Project, Change PLC Type", then selecting from the drop-down list. If you want to know the specifications for the FX3U(C) model, then download the Mitsubishi hardware manual and look it up.

 

[Sergei Troizky]

Treenifer, your instructions are not clear, but this is the best interpretation that I can make.[/URL]

As far as I understand, he needs one physical input to be the shift register input source, and another physical input to shift the data.
Anyways, driving a shift instruction in non-differential format is a common mistake. Either the condition or the instruction must be of P format.

All this being said, I still don't understand what good are these explanations in lack of basic knowledge of PLC.

BTW, Lancie, what is the reason of using R register in your code, not D?
And why not SFTR?