Need to write a summary to justify replacing SLC 500 and DeviceNet in 2020.Any advice

Good Morning ,

I'm finally getting through to upper management about the need to start eliminating our SLC 500 PLC's and Devicenet . I would say that about out of 95 machines , about 82 of these have SLC 500 PLC's , DeviceNet , Panelview Plus 6 HMI's , etc.

My question is , I imagine many of you had to explain to the upper management staff , that don't really understand , how critical it is to "keep step" with technology , and make sure that we are caught in a bad situation .

Do you guys have any examples of justification summaries that you needed to write or explain that got the finanicial approval to start replacing this soon obsolete equipment ?

Thanks so much in advance ,
Have a great day.

These are the best arguments I can give:
Newer PLCs and networks have better diagnostics --> less downtime.
Newer PLCs have better communication --> better integration into a plant-wide MES/ERP.
Old PLCs getting the "obsolete" status --> migrating to a newer PLC avoids costs for progessively more expensive spare parts.

I'm trying to convey how important this is with half a plant running on PLC5's and the other half reliant on Flex Ex. Both completely obsolete...

One argument I put forward is that replacing before failure takes two weeks downtime. Replacing after failure takes 4 months as a CAPEX request would have to be put forward and the logic in almost all the PLC's has to be redefined and re-written.

If you do a replacement on a rush, there's more pressure and less time for testing outside manufacturing and **** ups will be more expensive.

Doing replacements in a hurry also means that you won't get as much spares that could save you down the line while your replacements are ongoing... or in other words, a replacement program can last 4 years if done in time as the machines that get upgraded provide spares for the ones that keep on running.
Once you're into replacing failed systems, those spares are non existent and your CAPEX may end up being done in a much tighter time frame. This is normally something money people understand.

One thing that got the operations manager excited about the whole PLC replacement project was that because comms are much better on new PLC's, the controls will be much more responsive and the operators won't have to click, wait for half a minute and then do something.

One more argument:

On some machines, simply changing the PLC to something a factor 100 more powerful will give a small but significant increase in production, simply because the sequence runs through faster with less waiting between steps. Not much, but 1% or 2% increase in production could mean that much more in profits.

Obsolescence is the best argument, spare part prices for old SLC 500 are higher compared to latest models.

I agree. I just emailed a quote request to my Rockwell distributor for SLC 500 components .

An all to common issue.
We recently had a major Network issue due to sharing fiber with IT. As their VLan traffic increased along with the OT ka-boom big issue. Had been working on for 2 years to get $$.
Told my boss you sometimes make me feel like Chicken Little. Well Guess what fell today?

It is difficult to convince management to upgrade a control system. Generally, it will not increase productivity. The only savings is in down time, and/or rework due to failures.

Ken Moore said:

It is difficult to convince management to upgrade a control system. Generally, it will not increase productivity. The only savings is in down time, and/or rework due to failures.

Click to expand...

agreed because PLCs are heavy duty and can last very long. We can upgrade partially and keep some spares.