NT21 - Screen Function and PLC Address

[LD_M 2]

Hello,

In an NT21 screen, how do you determine the plc address of the switch?.  In my NT21 hmi, there are 4 screens ( functions ) and each screens has 4 switches,  the switches plc address are exactly pointing to the same address.  I could not determine the exact / individual plc bit address, since all are having the same addresses.

I tried opening the nt21 program using the NTST4.8 software, but I could not see the correct address.  A converted NT21 to NS program, still gives the same plc address...the same for all the 4 screens.

Anyone who have work with NT21 hmi? could you give me a link to manuals or guidelines, on how to know the exact plc addressing?

Appreaciate all the help.

cheers.

[gtsuport 61]

Do you have the plc code that was used with the NT21?

They may have used the current screen number (PLC Notify area) along with the bit address in the plc logic for control.

This is absolutely just a guess.

[LD_M 2]

You are right, gtsupport. 

On screen 1, the function tab is using a notify bit, and the plc address bit is D0001212.  In the plc program, the channel 12 points to channel 70. 

In another screen, screen 2, the function tab is also notify bit, with the same plc address bit also D0001212.  The same goes with screen 3, 4,and 5.  They are all pointing to the same plc address bit of D0001212.  

Is there a way to determine the exact / unique plc address bit? given with this information only? I have the original hmi and plc code, and I am using NTST 4.83.

The instruction details in the NT manuals are not clear enough, to understand the logic, on how to go about linking the screen toggle bits with the actual plc address.  Do you know any manuals / pdf , that could help in understanding more the issue?

Thanks you.

cheers.

 

[IO_Rack 181]

I took a brief look at the programs again. I think you are understanding the addressing OK. The PLC is making the decisions based on the screen number that is written (PT Control Area) from the PLC to the PT.

In NTST, click on Tools > PT configuration... then click on the Control/Notify Area tab. The PLC can write a screen number into D00000 and the PT will switch to that screen.

I do not have much time but I did follow D12.12 where it makes a decision based on Ch88 where it writes to D00000. Have a look at rung number 203 in the original PLC file. Be sure to look at the bits in Ch88. This looks fairly complex.

[LD_M 2]

Thanks for the information.

I am currently replacing the C200H with CJ2M.  working with the informations you have provided.  I am doing it, rung by rung, since a lot of variables are unknown.

Today, I was able to test run the machine, without product yet.

Cheers.

 

[IO_Rack 181]

1.  I did the conversion myself and I received no errors or warnings. CX Programmer does a good job converting especially since there were no complex instructions used in the original program. I can understand your caution though.

2.  Concerning your variables... Do you know how to back up the memory? (HR, DM, etc...)

[LD_M 2]

The C200H cpu and its i/o components were already removed, and I installed the CJ2M.  Yes, I know how to do the back-up procedures, but unfortunately, I could not perform the back-up for the HR and DM.  I could no longer establish comms with the old cpu. 

Thanks.