Device Net/HMI help

Hello Guys,

I'm in the process of phasing out these Eaton QC Port Device Net MCC buckets in our local WWTP. They are no longer supported by Eaton or any body for that matter. So I'm retro fitting the MCC bucket with regular contactors, ISO relays, and simple discrete/analog inputs are outputs for simplicity and further ease of troubleshooting support.

I'm doing a "test" mcc bucket first before proceeding with the rest. So far I've been able to re work the logic to work with my new programming and Bypass the DN inputs and outputs and or get rid of them as they will no longer be used. The issue is I have one status bit for the blower motor that indicates "Blower Running" on the HMI screen as well as turn the motor icon red when motor is running on the HMI. I tried writing a value of 1 to the PLC address that the HMI talks with but it cycles from 0 to 1 and back to 0

*This DN "Blower Running" input comes from Local:4:I.data[6] (Module 4 is the DN Scanner) and eventually makes it's way to "Local_S4_N60_POL_I.ExtendedData23.7" bool bit

There is a program on RSLogix 5000 labelled "DeviceNetInputs" with a subroutine called "local_S4InputsRoutine". Here there are two CPS instructions in series on rung 6, They look like this:


CPS
Source - Local:4:I.data[6]
Dest - Local_s4Inputs[24]
Length - 34
(first one, Taking data from the DN scanner DINT and copying it to SINT data type)

CPS
Source - Local_S4Inputs[24]
Dest - Local_S4_N60_POL_I
Length - 1
(second one, copying from SINT to "_0044_D77D_DNA_I_F381BBE4 data type)

I realized that the HMI is taking this "blower running" indication from "Local_S4_N60_POL_I.ExtendedData23.7" which is a Bool data type, So I tried to put and OTE instruction at the end of a new rung addressed to Local_S4_N60_POL_I.ExtendedData23.7 and have my new motor input running signal turn the OTE to true which would write a value of 1 into Local_S4_N60_POL_I.ExtendedData23.7

This worked for about a second then it starts toggling from true to false even though my motor running indication stayed true. I'm guessing this is happening because the old device net bit is still trying to write a value of 0 into the register. The problem is I have no idea how to stop device net from doing this. This is the last step to eliminating device net and testing this motor out. Although its just indication, I want the operators to receive the right information.

Any help is appreciated.

- TEX

Find the appropriate bit in the Local_s4Inputs array.
Insert your OTE logic for the blower in-between the two CPS instructions. Your OTE will Point at the Local_s4Inputs[] array.
If you want the ability to turn devicenet on/off you can create another bit to select between either your new logic or leaving the value unchanged.

AustralIan said:

Find the appropriate bit in the Local_s4Inputs array.
Insert your OTE logic for the blower in-between the two CPS instructions. Your OTE will Point at the Local_s4Inputs[] array.
If you want the ability to turn devicenet on/off you can create another bit to select between either your new logic or leaving the value unchanged.

Click to expand...

I can't seem to find out which bit is corresponding to Local_S4_N60_POL_I.ExtendedData23.7. Nothing is labeled in any of those arrays. The biggest issue for me is that those CPS instructions transfer several other motors and their inputs to the HMI as well so I defintely cannot make a mistake. Would it help if I attached a copy of the program?

I seem to have found what I think is the corresponding address to "Local_S4_N60_POL_I.ExtendedData23.7"

I believe it is Local_S4Inputs[49].7

I've tried to toggle that bit true by using and OTE to write a value of 1 into Local_S4Inputs[49].7 but it does not transfer over to Local_S4_N60_POL_I.ExtendedData23.7

I didn't quite understand what you meant by putting and OTE between the two CPS bits. Any chance you can show this is Rung Logic for me?

I'm going to attach the existing program. In there you can see the CPS instructions on program labeled "devicenetinputs" and subroutine "LocaL_S4InputsRoutine" rung 6.

Also under program "MainProgram" Subroutine "totalizers" rung 33 shows the bit I am trying to write to (BLR_230_Running)

That logic was almost certainly generated automatically by the DeviceNet Tag Generator utility.

I don't have an automation workstation right now (it's Memorial Day in the US an I'm actually taking the day off) but I can peek at it tomorrow.

Ken Roach said:

That logic was almost certainly generated automatically by the DeviceNet Tag Generator utility.

I don't have an automation workstation right now (it's Memorial Day in the US an I'm actually taking the day off) but I can peek at it tomorrow.

Click to expand...

I ended up going a different route, I was able to figure out how to get onto the offline version of iFIX HMI software and just change the existing tag PLC address to a new one that I created on RSLogix 5000. The route I was trying to take wasn't working for me. But please feel free to have a look anyway as I'm still curious on how to make it work how I originally intended.