Adapting onboard PLC for Fuel Cell-Battery Locomotive Retrofit

[yarobeyt]

Hello,

I am doing research project focused on the retrofit of a diesel locomotive into a hydrogen-fuel-cell-battery hybrid locomotive. The locomotive we are retrofitting (~20 years old) was controlled by an Allen Bradley SLC 5/04 modular processor with 1746 series components. We would like to reuse the PLC onboard the locomotive as the control logic has already been programmed for the system. We tested the PLC and confirmed power still turns on all the modules but do not know how to access the pre-existing software/code.

I have a few questions for anyone with experience or willing to answer.

What software do we need to install in order to access the code/program stored on this PLC? If we wanted to add our own lines of programming logic to the PLC how can this be done?

Furthermore, the modern hydrogen systems we are integrating into the locomotive communicate using the CAN Bus protocol, CAN2.0B. Therefore, we would like to add the 1747-SDN ALLEN BRADLEY module to our chassis, as it appears the Devicenet Scanner Module will offer the PLC the option of using a CAN communication protocol..?

We would like to be able to connect to the current PLC with a laptop, download the pre-existing program, and re-program the PLC adding sections to the code that cooperate with our Hydrogen Power System.

Can you offer any suggestions or help on integrating this to our system? Can you offer any tips or proposals on components or software we would need to accomplish this?

Thank you!

 

[alan_505]

You will need to buy RSLogix500, contact your local Rockwell distributor for pricing.
Is there anything connected to the serial port?

The serial port can be configured for a few different types of communication not all will allow you to get online, and you may need to use the DH+ port ($$$$).

Note, when you upload the program out of the processor it will have no comments, are you able to get a copy of the original program?

As for using the DeviceNet to talk to CanBus someone else will need to comment on that.

 

[alan_505]

Also note that the majority of SLC parts are no longer going to be available from Rockwell from September 2024, but a lot are not available new anymore as now.

 

[plvlce]

For both accessing and altering the program, the software you need is 'RSLogix 500'. You will also need RSLinx for communication, but the 'Lite' version of that is free and will come with RSLogix. Hopefully whoever programmed it did not lock it behind a password that you cannot obtain.

Is the DB9 connector on the CPU in use? If not, it is likely still set for the default communication setting and all you will need to communicate is a null modem cable and a programming computer with a serial port (some USB to serial converters will work).

If the DB9 connector is in use, you will likely need to identify what protocol it is set for... I'll leave that alone unless it turns out to be relevant. The round mini DIN connector is for DH+; if you're willing to shell out a grand or more for a 1784-U2DHP adapter you can also connect that way. For obvious reasons it's preferred to use the other port though.

Although DeviceNet is a CAN based network, I've never heard of a 1747-SDN being used for anything other than specifically DeviceNet networks. Maybe one of our gurus can say more. You might be able to use it in combination with a 3rd party converter.

 

[James Mcquade]

When you power up the slc processor, does it go into run mode or are there red flashing lights?

i would contact your local rep for assistance.
get a list of all the i/o cards, take pictures if you have to.
the standard version may not work with devicenet, controlnet.
if i am wrong, someone please correct me.
james

 

[yarobeyt]

When you power up the slc processor, does it go into run mode or are there red flashing lights?

i would contact your local rep for assistance.
get a list of all the i/o cards, take pictures if you have to.
the standard version may not work with devicenet, controlnet.
if i am wrong, someone please correct me.
james

It goes into run mode. (green and other colored lights appear and sometimes flash on the modules). That's why we are hoping to be able to pull some data from the PLC.

I should mention I have an excel spreadsheet of the I/O mappings and descriptions as well so I do know the types of signals being sent.

 

[yarobeyt]

For both accessing and altering the program, the software you need is 'RSLogix 500'. You will also need RSLinx for communication, but the 'Lite' version of that is free and will come with RSLogix. Hopefully whoever programmed it did not lock it behind a password that you cannot obtain.

Is the DB9 connector on the CPU in use? If not, it is likely still set for the default communication setting and all you will need to communicate is a null modem cable and a programming computer with a serial port (some USB to serial converters will work).

If the DB9 connector is in use, you will likely need to identify what protocol it is set for... I'll leave that alone unless it turns out to be relevant. The round mini DIN connector is for DH+; if you're willing to shell out a grand or more for a 1784-U2DHP adapter you can also connect that way. For obvious reasons it's preferred to use the other port though.

Although DeviceNet is a CAN based network, I've never heard of a 1747-SDN being used for anything other than specifically DeviceNet networks. Maybe one of our gurus can say more. You might be able to use it in combination with a 3rd party converter.

The DB9 has nothing connected to it; so this may be the case.

What do you mean by 'null modem cable'? If we connect to the PLC via the serial port communication do you know how we could use this to access the program stored on the SLC 5/04?

Also, I bought this cable on Amazon in hopes in would let us connect to the PLC.
https://www.amazon.ca/dp/B07FRWNDW1?...t_details&th=1

I also attempted to install RSLogix Micro, RSLinx, and RSLogix Emulate 500 but was unable to get the latter two software to open. In general I couldn't figure out how to connect to the PLC software once the SLC 5/04 was powered up.

The locomotive is already wired for control of the system through the old SLC 5/04 PLC. So it in theory seems simpler to use the pre-existing wiring.
We are open to other options of control as we want the locomotive to operate with ease and just as smooth as other locomotives in the industry.

 

[plvlce]

With the cable you may be able to establish communication using RSLinx to the point you can 'see' that you are connected, assuming Channel 0 (the DB9 connector) still has its default settings.

You will not be able to upload/download or go online with the program without a full version of RSLogix 500 -- iirc the 'Micro' version is only for the MicroLogix controllers, it does not support SLC.

As a side note regarding terminology, once you get connected you will first want to 'Upload' the program to your PC (and then save a backup in case anything goes wrong).

Reusing the wiring is certainly simpler, but be aware the Rockwell is obsoleting the system so you will likely run into issues in the future if you need replacement parts.

EDIT:

What do you mean by 'null modem cable'?

A standard serial cable connects each pin directly to the corresponding pin on the other side, ie pin 1 on one end connects to pin 1 on the other, pin 2 connects to pin 2, etc. In a null modem cable the send and receive pins (usually pins 2 and 3) crossed.

The reasons for this are beyond the scope of this topic, suffice to say if you have a programming cable designed specifically for SLC this is all already built in so you shouldn't need to worry about it.

RSLinx is the software that handles all actual communication. You will need to create an RS232 driver in it assigned to the correct port, then first try using the 'auto-configure' button.