Modicon M580 Buying Guide

Bottom line: pick the M580 processor by the number of racks and the I/O count you must support, then decide whether redundancy or SIL rating is a hard requirement. Add communication modules only after the embedded ports on the CPU have been counted, because a BMEP58 already provides Ethernet service and device-network ports.

This guide covers the Modicon M580 processors, redundant PACs and Ethernet modules held in the PLC Source PRO catalog. Every SKU below links to a live product page. For the wider range, see the Schneider Electric collection; for a rack-level check, use the contact page.

How do you size a Modicon M580 processor correctly?

Count racks, discrete I/O and analog channels first, then choose the smallest BMEP58 that covers all three with spare capacity. Add the S suffix only when SIL 3 is a project requirement, and move to the BMEH58 pair only when hot standby is specified. Communication modules come last, after the embedded Ethernet ports are mapped.

Three datasheet figures separate the M580 tiers in this catalog:

• I/O ceiling: the BMEP581020H supports 1,024 discrete and 256 analog I/O, while the BMEP586040 supports 6,144 discrete and 1,536 analog I/O.
• Rack count: the BMEP582020H and BMEP582040H support 4 racks; the BMEP584040S supports 8 local racks plus 16 remote racks.
• Redundancy: the BMEH582040C and BMEH586040 are redundant processor modules rated at 650,000 hours MTBF, distinct from the single-processor BMEP58 range.

Which M580 selection dimensions actually change the part number?

Dimension	What changes across the range	Buying consequence
Discrete and analog capacity	1,024 / 256 I/O on BMEP581020H up to 6,144 / 1,536 I/O on BMEP586040	Size for the finished plant, not the first machine
Rack support	4 racks on BMEP582020H, 8 local plus 16 remote on BMEP584040S	Remote drops consume rack allowance even when they sit in another building
Program memory	4 MB on BMEP581020H, 8 MB on BMEP582020H, 24 MB on BMEP585040, 64 MB on BMEP586040	Motion, HART and historical buffering grow memory faster than ladder logic
Safety	SIL 3 per IEC 61508 on BMEP584040S only	A standard BMEP58 cannot be substituted into a safety loop
Redundancy	BMEH582040C (8 MB) and BMEH586040 (64 MB) use paired processors	Budget for two CPUs, two racks and the synchronisation link
Communication	Embedded Ethernet service and device-network ports on the CPU; BMENOC0301 and BMENOC0321 add rack-mounted Ethernet; BMENOS0300 is a 3-port EtherNet/IP switch	Count embedded ports before adding a module
Legacy I/O retention	140CRA31908 presents Quantum I/O to an M580 Ethernet RIO network	Allows a staged migration without rewiring every Quantum drop

Which M580 configuration fits your project?

• If you are upgrading a Quantum system in stages: fit a BMEP582020H as the new controller, keep the existing Quantum I/O and add 140CRA31908 adaptors at each drop. This preserves field wiring while moving the control layer to Ethernet RIO.
• If you are building a single machine or small line: BMEP581020H covers 1,024 discrete and 256 analog points with 4 MB of program memory and 270 mA current draw at 24 VDC.
• If the line will grow to several racks: start at BMEP582040H for 4 racks and 72 application-specific channels rather than buying a second CPU later.
• If downtime is unacceptable: use a BMEH582040C or BMEH586040 redundant pair. The BMEH586040 adds 64 MB of program and data memory and supports 31 remote I/O stations.
• If the process is safety-rated: BMEP584040S is the only SIL 3 processor in this catalog, with 16 MB of program plus 4 MB of safety memory and 8 local racks.

Which M580 SKUs are in the PLC Source PRO catalog?

All 12 links below returned HTTP 200 on 7 November 2026. Specifications are the datasheet values published on each product page; confirm the firmware revision before ordering for a safety function.

Model	Function	Key specification	Product page
BMEP581020H	M580 processor	1,024 discrete / 256 analog I/O, 4 MB program, 270 mA at 24 VDC	View BMEP581020H
BMEP582020H	M580 processor	2,048 / 512 I/O, 4 racks, 8 MB program	View BMEP582020H
BMEP582040H	M580 processor	2,048 / 512 I/O, 4 racks, 72 application channels	View BMEP582040H
BMEP584040S	SIL 3 safety processor	4,096 / 1,024 I/O, 16 MB program + 4 MB safety, 8 local / 16 remote racks	View BMEP584040S
BMEP585040	M580 processor	5,120 / 1,280 I/O, 24 MB program, 4 GB flash	View BMEP585040
BMEP586040	M580 processor	6,144 / 1,536 I/O, 64 MB program, 31 RIO stations	View BMEP586040
BMEH582040C	Redundant processor	8 MB program / 768 kB data, 650,000 h MTBF	View BMEH582040C
BMEH586040	Redundant processor	64 MB program and data, 31 RIO stations, 64 distributed devices	View BMEH586040
BMENOC0301	Ethernet communication module	Modbus TCP and EtherNet/IP scanner, RSTP, embedded web server	View BMENOC0301
BMENOC0321	Ethernet communication module	M580 rack-mounted Ethernet, service and device-network ports	View BMENOC0321
BMENOS0300	Ethernet switch module	3 ports, EtherNet/IP, 3.3 W at 25 °C	View BMENOS0300
140CRA31908	Ethernet RIO drop adaptor	3 Ethernet ports, EtherNet/IP and Modbus TCP, 5 VDC at 1.2 A	View 140CRA31908

Which M580 parts can be exchanged, and which cannot?

• Within the BMEP58 range: all processors use the same M580 rack and programming environment, but I/O capacity, rack count and memory differ. Moving from BMEP581020H to BMEP582020H is a reconfiguration, not a drop-in spare.
• BMEP58 versus BMEH58: they are not interchangeable. A BMEH58 system needs two processors, a dedicated synchronisation link and a matched rack pair; a single BMEH58 module will not run as a standalone CPU.
• Standard versus safety: BMEP584040S is the only SIL 3 processor listed here. A standard BMEP58 must not be used to replace it in a safety instrumented function.
• Rack families: M580 processors mount in M580 X80 racks. The BMXXBP0600 and BMXXBP1200 racks listed for M340 are different parts and do not substitute for an M580 rack.
• Communication: BMENOC0301 and BMENOC0321 are not pin-for-pin equivalents; port count and network role differ. BMENOS0300 is a switch, not a scanner, and cannot replace a BMENOC module.
• Quantum I/O: 140CRA31908 keeps Quantum I/O alive on an M580 RIO network, but it does not convert Quantum I/O into X80 I/O. Module references remain Quantum references.

Frequently asked questions

Is BMEP584040S a safety processor?

Yes. The product datasheet lists SIL 3 per IEC 61508 and SIL 4 per EN 50126, with 16 MB of program memory and 4 MB reserved for safety data. It also supports 4,096 discrete and 1,024 analog I/O across 8 local and 16 remote racks. Confirm the safety certification revision and the project-specific SIL calculation before ordering.

What is the difference between BMEP58 and BMEH58?

BMEP58 is a single-processor PAC. BMEH58 is a redundant pair: two processors, a synchronisation link and matching racks, so one unit can take over without stopping the process. BMEH582040C offers 8 MB of program memory and BMEH586040 offers 64 MB, both rated at 650,000 hours MTBF.

Do I need BMENOC0301 if the CPU already has Ethernet ports?

Not always. The M580 CPU already provides an Ethernet service port and device-network ports. A BMENOC module adds rack-mounted Ethernet capacity, scanner services and separation between the control network and the plant backbone. Count the embedded ports and the required network segments before adding a module.

Can I keep my existing Quantum I/O on an M580 system?

Yes, through Ethernet RIO drop adaptors. The 140CRA31908 presents Quantum I/O to an M580 RIO network over EtherNet/IP and Modbus TCP, with three Ethernet ports and a 5 VDC, 1.2 A supply requirement. The Quantum modules stay Quantum modules; they are not converted to X80.

Need help with an M580 migration plan?

Send your rack layout, I/O count and network drawing to the PLC Source PRO contact page. We will map each existing drop to an M580 rack or a 140CRA31908 adaptor and confirm the processor tier against the datasheet. For the older platform, see the Modicon Quantum 140 buying guide; for smaller racks, see the M340 and X80 buying guide.