Allen-Bradley PLC: Cost Controller’s Guide to Smart Buying & Common Pitfalls

What you’ll find here

I manage procurement for a mid-sized automation integrator. We spend about $120,000 annually on PLC hardware, mostly Allen-Bradley. Over the past 6 years, I’ve tracked every invoice, compared quotes, and definitely made some expensive mistakes. Here’s what I wish someone had told me before I started buying Allen-Bradley PLCs.

1. Is Allen-Bradley really more expensive than Siemens?

Short answer: yes, the list price is usually higher. But the total cost of ownership (TCO) is not that simple.

I compared specs on a ControlLogix 1756-L83E against a Siemens S7-1500 setup for a mid-sized line. The Allen-Bradley controller plus basic I/O modules was about 18% higher in upfront cost.

However — and this is where the TCO kicks in — our team already knows Studio 5000. Training a new tech on Siemens TIA Portal would have cost us roughly $4,200 in lost time per project for the first 6 months (note to self: I should have tracked that more carefully). If you’re starting from scratch, the gap narrows. If you already have an installed base, switching vendors has hidden costs that don’t show up on the first quote.

2. What’s the biggest hidden cost when buying a new Allen-Bradley PLC?

I wish I had tracked this from the start: accessories and software subscriptions.

Take a CompactLogix 5380 system. The controller itself is $3,200. But you’ll likely need:

• A power supply ($200–$500 depending on backplane)
• Ethernet cables (not always included)
• A memory card (if you want local backup)
• Studio 5000 license (either $1,200 annual subscription or $6,000 perpetual)
• Racks, mounting hardware, terminal blocks

We didn’t have a formal process for checking “what’s NOT included” before quoting. The third time we got a surprise on an invoice, I finally created a checklist. I’m not a software licensing expert, so I can’t speak to every option. What I can tell you from a procurement perspective is: add 12-15% to the controller price for accessories. That’s my rule of thumb after 6 years of data.

3. New vs. used Allen-Bradley PLC: is refurbished worth it?

I bought used MicroLogix 1400 units twice. First time: saved $600 per unit. Second time: had to re-order after the first batch failed within 3 months. The “cheap” option resulted in a $1,200 redo when quality failed.

Here’s my rule now: used is fine for non-critical spares or test benches. For production lines, I only buy new or from a certified re-seller with a warranty. I don’t have hard data on industry-wide defect rates for refurbished units, but based on our 5 years of orders, my sense is that quality issues affect about 8-12% of first deliveries from non-certified sellers.

4. Should I buy the new firmware version just because it’s available?

When the new CompactLogix 5480 launched, our senior engineer wanted it. I said “let’s wait one revision.”

Had 2 hours to decide before the deadline for a project quote. Normally I’d test a new controller for a month on a bench, but there was no time. I went with our usual 5380 based on trust alone.

Turns out, version 1.0 of the 5480 had a known issue with certain I/O modules. We would have been stuck waiting for a patch. Hit “confirm” on the 5380 order and immediately thought “did I make the wrong call?” Didn’t relax until the system booted clean.

My policy: never deploy firmware version 1.0 on a production system. Wait for at least one major revision. The vendor who lists all known issues upfront — even if they look worse — usually saves you more in the long run.

5. How to negotiate the best price on a new Allen-Bradley PLC?

After comparing 6 vendors over 3 months using my TCO spreadsheet, I found that list price is not real price. Here’s what works:

• Buy in bulk — even 3-5 units unlocks a 5-8% discount from distributors
• Ask for “bundle pricing” — controller + modules + software = better deal
• Check the education channel — Allen-Bradley offers training kits at a discount (great for test benches)
• Time your purchase — we’ve seen 10% off in Q4 (year-end inventory pushes)

One more thing: the “free setup” offer from one distributor actually cost us $450 more in hidden fees on software activation. I now ask “what’s NOT included” before “what’s the price.”

6. How do I know if I’m paying too much?

I built a cost calculator after getting burned on hidden fees twice. Here’s a basic check:

• Controller price — compare with Rockwell Automation’s MSRP (verify current pricing)
• Module pricing — typically 30-40% of controller cost each
• Software — if they quote a perpetual license, check if support fees are included
• Shipping + handling — can be 5% extra if not specified

Our procurement policy now requires quotes from 3 vendors minimum. That one rule cut our average PLC cost by 9% in the first year.

7. What about the “3000 watt power inverter with battery charger and transfer switch” and “3 bank boat battery charger” — unrelated but worth mentioning?

I’m not an electrical engineer, so I can’t speak to inverter integration. But from a procurement perspective: if you’re buying a 3000 watt power inverter with battery charger and transfer switch for a backup system, apply the same logic. Ask what cables, mounts, and installation fees are NOT included. A cheap inverter that needs $200 in adapters is not a cheap inverter.

Same for a 3 bank boat battery charger — I saw a $50 price difference between two models that turned out to be $120 different once you added the correct mounting bracket and connectors.

8. Quick tip: “how to reset fuel pump” search — relevant to PLC maintenance?

If you're a maintenance tech dealing with a PLC-controlled fuel pump reset, you’re probably searching for a specific model’s procedure. I can’t give you that (not my area). But I can tell you: if your PLC loses power and the fuel pump won’t reset, check the safety interlock logic first. Most Allen-Bradley CompactLogix systems have a dedicated safety routine that requires a manual reset after power cycle. That’s not a bug — it’s intentional. And if you’re calling a vendor, be ready with the controller serial number and firmware version. It saves 20 minutes of back-and-forth.