If your CPU 315-2DP has just failed, you already know the real problem: the SIMATIC S7-300 family is being phased out, and new units get harder to source every year. The good news: a Siemens S7-300 CPU 315-2DP replacement is still easy to get if you pick the right route. This guide compares the four realistic options — the official successor 6ES7315-2AH14-0AB0, a tested used or refurbished CPU, a professional repair of your existing unit, and a full migration to S7-1500. We supply and repair S7-300 CPUs every week, so the notes below come from bench work, not from datasheets.
Why You Need a CPU 315-2DP Replacement Plan Now
The CPU 315-2DP was the mid-range workhorse of the S7-300 line: one MPI port, one PROFIBUS DP master/slave port, and enough memory for most machine and line control jobs. Thousands of packaging lines, conveyors, and machine tools still run on it today.
Siemens has moved the whole S7-300 family into phase-out status. Factory-new stock is shrinking, lead times are stretching, and prices keep climbing. If this CPU is the brain of a critical machine, waiting until it dies is the most expensive plan you can have. A Siemens S7-300 CPU 315-2DP replacement ordered today, on your terms, always costs less than an emergency purchase during a shutdown.
In our repair lab, failed CPU 315-2DP units usually come in for one of three reasons: a damaged PROFIBUS port (often after hot-plugging a DP connector), a corrupted Micro Memory Card after power loss during a write cycle, or aged capacitors causing random restarts. All three are fixable — but you need to decide fast when the line is down.
Option 1: The Official Successor — 6ES7315-2AH14-0AB0
Within the S7-300 family itself, Siemens replaced the older 6ES7315-2AG10-0AB0 with the newer 6ES7315-2AH14-0AB0 CPU 315-2DP. For most users this is the smoothest Siemens S7-300 CPU 315-2DP replacement because the mechanics, wiring, and programming stay almost the same.
Before you swap, run these checks:
- Program location: your logic lives on the MMC card, not inside the CPU. Move the card or download the program with STEP 7 before the old unit fails completely.
- Memory size: the 2AH14 offers more work memory than the 2AG10. If your program is near the old limit, the successor gives you headroom.
- Hardware config: update the CPU type in HW Config if your project still references the 2AG10, then recompile and download.
- DP network: test all PROFIBUS slaves after the swap. Baud rate and address stay on the card, but a clean power-up check avoids surprises.
If you want to see how Siemens CPU generations differ inside the S7-300 family, our S7-300 CPU module comparison shows a typical standard-vs-compact decision in detail.
Option 2: A Tested Used or Refurbished CPU 315-2DP
When the line is down and you need identical behavior, the fastest Siemens S7-300 CPU 315-2DP replacement is the same part number from the used market. Swap the unit, insert your MMC, power on, and the machine is back. No re-engineering, no re-training, no documentation updates.
Buy used only when the seller can prove condition. Ask for:
- A functional test report, not just “pulled from a working line”
- Clear photos of the MPI and DP connectors — bent pins are common
- A written warranty (we give 1 year on every unit we ship)
We keep the 6ES7315-2AG10-0AB0 CPU 315-2DP and related S7-300 modules in stock, tested on our bench before shipping, with no minimum order quantity.
Option 3: Repair the CPU You Already Have
Repair is the option most buyers overlook — and often the cheapest one. A standard CPU repair takes 3-5 days in our lab, and our measured fix rate is 99.5%. Compared with buying new, repair can save up to 75% of the cost, and every repaired unit carries a 1-year warranty.
Repair makes the most sense when:
- The failure is on the DP port, power section, or card slot — classic bench jobs
- You have a spare CPU running and can wait a few days
- You want a tested backup on the shelf instead of gambling on one unit
If you are weighing repair against replacement for other obsolete parts too, read our guide on how to repair, refurbish, or replace obsolete parts — the same decision logic applies.
Not sure which route fits your situation? Send us your part number and a photo of the fault (or the failed unit’s behavior). Our engineers answer with a concrete recommendation — successor, used stock, or repair — usually within one working day: [email protected].
Option 4: Migrate to S7-1500
Migration is the right answer when the machine has 10+ years of life ahead and you want a platform with active factory support. But be honest about the cost: a CPU 315-2DP replacement by an S7-1500 is a project, not a swap. You will convert the program in TIA Portal, change the rack and I/O wiring, replace PROFIBUS DP with PROFINET or add a DP module [需核实], and plan real commissioning downtime.
Our rule of thumb: migrate on your schedule, not on the failed CPU’s schedule. Secure a working CPU 315-2DP first — successor, used, or repaired — then plan the migration during a planned shutdown.
CPU 315-2DP Replacement Options Compared
The table below sums up the four routes for a Siemens S7-300 CPU 315-2DP replacement. Use it together with the 5-step checklist that follows.
| Option | Typical Downtime | Relative Cost | Warranty | Engineering Effort |
|---|---|---|---|---|
| Successor 6ES7315-2AH14-0AB0 | Hours (swap + checks) | Moderate | 1 year (from us) | Low — HW Config update |
| Tested used / refurbished CPU | Hours (direct swap) | Lowest | 1 year (from us) | None |
| Repair your existing CPU | 3-5 days | Low — saves up to 75% vs new | 1 year | None |
| Migrate to S7-1500 | Days to weeks (planned) | Highest | Factory warranty | High — re-engineering |
How to Choose Your Siemens S7-300 CPU 315-2DP Replacement in 5 Steps
- Confirm the exact part number on the front label (2AG10, 2AH14, or another variant). One digit difference can mean a different interface set.
- Secure your program first. Pull the MMC or upload the project with STEP 7 if the CPU still starts. The card is your insurance.
- Decide by downtime. Line down now? Order a tested used CPU or the successor. Line running on a spare? Send the failed unit for repair.
- Test before installing. Check DP communication with all slaves and run the machine through one full cycle before closing the cabinet.
- Keep a backup on the shelf. With the S7-300 discontinued, one spare CPU is cheap insurance against the next failure.
FAQ
Is the Siemens S7-300 CPU 315-2DP discontinued?
Yes. The S7-300 family is in official phase-out, and the CPU 315-2DP is no longer actively promoted. New stock is limited and expensive, which is why used, refurbished, and repaired units now cover most demand.
Can I replace 6ES7315-2AG10-0AB0 with 6ES7315-2AH14-0AB0 directly?
In most cases yes. The 2AH14 is the designated successor with the same mounting and interface layout. Update the CPU type in HW Config, move your MMC, and test the DP network after the swap. Check memory usage if your program is close to the old limit.
Will my program run on the replacement CPU?
Yes, if it is stored on the MMC. The card holds the program, hardware configuration, and DP settings, so moving the card moves the machine’s brain. If the old CPU is dead and the card is damaged too, you need your offline STEP 7 project backup.
How long does a repaired CPU 315-2DP last?
A professional repair replaces the failed components, not just the symptoms. Our repaired units carry a 1-year warranty, and in practice they stay in service for years when the cabinet cooling and power supply are healthy.
Get Your CPU 315-2DP Replacement Fast
A Siemens S7-300 CPU 315-2DP replacement does not have to mean weeks of downtime or a forced migration. Tell us your part number and what happened — we will tell you honestly whether a successor unit, tested used stock, or a repair is your fastest way back to production. We hold 100,000+ SKUs in stock, all tested, shipped within 48 hours — no MOQ. Send your inquiry to [email protected] or WhatsApp +86 15107352558.