ABB / AC500 controllers

An AC500 station is a terminal base plus a CPU plus I/O modules on terminal units. Four separate order lines before anything works, and the XC version cannot be identified by looking at it.

AC500 is the ABB modular PLC platform, with AC500-eCo as the compact variant. It turns up in New Zealand water treatment, building services and machine builds.

The three parts of an AC500 station

Get this right before ordering, because none of the parts work alone.

The terminal unit holds the wiring, so an I/O module can be swapped without touching a terminal. Same principle as the Phoenix Contact relay base and the Pilz surge plug: the consumable part is separate from the wired part.

That is good news on a failure. It also means a parts list that names only CPUs and I/O modules is incomplete.

The terminal base slot count is in the number

ARCNET versions exist as TB511-ARCNET, TB521-ARCNET and TB541-ARCNET.

If you are adding a fieldbus coupler to an existing station, count the free slots on the terminal base first. Running out means changing the base, which means rewiring the CPU.

One hard restriction

ABB states that the TB523-2ETH can only be used together with the PM591-2ETH.

It is not a general purpose four-slot base. Pair it with anything else and it will not work.

Backward compatibility

ABB notes these terminal bases are compatible with both previous AC500 CPU versions (R01xx) and newer ones (R02xx).

Useful if you are keeping an older station running: a current terminal base will accept an older CPU.

You cannot see whether a module is an XC version

An excellent detail from the ABB installation instructions, and one that will catch anyone buying used.

XC means eXtreme Conditions, for wider ambient temperature, humidity and vibration.

ABB states: terminal bases for use in extreme ambient conditions have no marking for the XC version. The figure 3 in the part number 1SAP3... on the label identifies the XC version.

So read the order number, not the module. If your installation is in an unheated building, a chiller room or a vibrating structure, and the original was XC, a standard replacement is not equivalent even though it is physically identical.

The wall mounting accessory is mandatory

Straight from the ABB installation instructions, and stated as a requirement rather than a recommendation.

When assembling AC500 modules with screws rather than DIN rail, the TA526 wall mounting accessory is mandatory. ABB warns that without it the modules can bend and be damaged during assembly.

If you are screw-mounting a station, that is a part to include.

AC500 CPUs

AC500-eCo, compact

PM554 and PM564 have no built-in real time clock. ABB supplies the TA562-RTC as a real time clock option specifically for those two CPUs.

If your application timestamps data or runs a time schedule, check whether that module is fitted. On a replacement it will not be included.

AC500 V2, modular

Confirmed order code: PM573-ETH is 1SAP130300R0271.

Newer generation

Safety

The S suffix marks the safety range, and safety modules need the safety terminal unit. The usual caution applies: a like-for-like replacement preserves the safety assessment, a substitution may not, and that decision belongs to whoever is responsible for the machine.

S500 I/O modules

Digital

Analog

Specialty

The FM502-CMS condition monitoring module needs a TF5x1 function module terminal base for direct interfacing to the CPU. It handles high frequency signals such as vibration, current, voltage and encoder speed. ABB specifies the PM592 CPU on the same TF5x1 for data storage and signal processing.

Networking and fieldbus

The part of AC500 that generates most of the confusion, because two different families both look like communication parts.

CI is out on the network, CM plugs into the CPU

So a CI is remote I/O and a CM is a fieldbus card. They are not alternatives, and a parts list that has one where it needs the other will not work.

If the part is in the cabinet next to the CPU, it is a CM. If it is in a remote box with I/O modules beside it, it is a CI.

CI communication couplers, remote I/O heads

The suffix is the protocol and it is not a variant. A CI501-PNIO is a PROFINET device and a CI501-MODTCP is a Modbus TCP device. Same base number, different networks entirely.

So the suffix has to match the network, not the CPU. That is the most common ordering error on this range, because the base number looks like the whole part number.

The node address is set on the coupler

Worth noting before a remote station is swapped.

CI couplers carry address switches, and the node address is set on the hardware rather than in the project. A replacement arrives with the switches at their default.

So note or photograph the switch positions before the old coupler comes off the wall. A correct coupler at the wrong address is invisible to the master and looks exactly like a dead unit.

CM communication modules, fitted to the terminal base

Master and slave are different modules

The distinction that matters most in the CM range, and it is easy to miss because the numbers are close.

A module that makes the AC500 the master of a network and a module that makes it a slave on somebody else's network are separate parts. On PROFINET, the CM579-PNIO is the controller side and the CM589-PNIO is the device side.

Both will fit the slot and only one will do the job. Tell us whether the AC500 is running the network or answering to one, and send the exact number off the module.

Slot count is the constraint on adding one

Worth checking before quoting an extension rather than after.

CM modules occupy slots on the terminal base, and the base is sized at build time. A TB511 has one slot; a TB541 has four.

So adding a fieldbus to a station on a single-slot base means changing the base, which means unplugging the CPU and moving the Ethernet connection. That is a shutdown job rather than a plug-in one.

Count the free slots first. The table further up this page gives the counts.

Onboard Ethernet and a CM are not the same thing

A CPU with an -ETH suffix has Ethernet through the terminal base connector. That covers programming, Modbus TCP and general TCP/IP.

It does not give you PROFINET, EtherCAT, PROFIBUS or DeviceNet. Those need a CM module even though the physical connector on an Ethernet-based fieldbus looks identical.

That is the same trap as everywhere else in industrial networking: RJ45 and CAT cable do not mean ordinary Ethernet rules apply. An EtherCAT segment off a CM579-ETHCAT cannot be branched with a switch, in exactly the way described on our Beckhoff junctions page.

CS31 is the legacy path

CS31 is the ABB legacy fieldbus, and it appears as both a coupler suffix and a terminal unit variant.

That matters on a migration. An AC500 can take over an existing AC31-era CS31 network rather than replacing the field I/O, which turns a rebuild into a controller swap.

If a plant is moving off AC31 and has racks of CS31 I/O still working, that is the question to ask before quoting a full replacement.

Where the configuration lives

So network parts are good spares. One of each CM and CI type you run covers every station on the site.

ABB does not make the plant switches

Worth saying plainly, because people ask.

ABB has no general industrial Ethernet switch range for factory automation. The AC500 networking parts above are fieldbus interfaces and remote I/O heads, not switches.

So the switches and the plant network infrastructure around an ABB installation almost always come from somebody else. We supply that side too, and the relevant ranges are Siemens SCALANCE, Schneider ConneXium, Allen-Bradley Stratix and Phoenix Contact Factoryline.

ABB's own switch products sit in substation and utility automation rather than plant, so if you have an AFS or AFF unit out of a switchyard, send the number and we will treat it separately.

Terminal units

The screw versus spring distinction runs through the terminal unit range. TU515 is screw and TU516 is spring, at 24 V DC. If your panel is wired for one, the other will not terminate.

The 230 V AC relay units are a different family again. Check the voltage before ordering.

Accessories

The TA521 battery is the one to act on before it fails. Same argument as every other platform with battery-backed memory. If nobody knows when it was last changed, change it while the plant is running.

Before ordering a replacement

Legacy ABB control platforms

Legacy ABB process hardware carries 3BSE and 3BHE order numbers. Those are the ones to send us.

What to send us

The 1SAP order code where you have it. It is what identifies an XC version.

Whether you need the terminal base and terminal units as well as the modules.

Which network the part sits on, and the exact suffix.

Whether the AC500 is the master or a slave, for a CM module.

The node address switch positions, for a CI coupler.

Screw or spring terminals, for a terminal unit.

What we can supply

Current production. AC500 and AC500-eCo CPUs, terminal bases, S500 I/O, terminal units, CM communication modules, CI remote I/O couplers and accessories, including XC versions. Quoted with a delivered lead time.

Discontinued. AC31, older AC500 V2 CPUs, S800 and S900 I/O, CS31 hardware, Advant hardware. Surplus and tested used.

The parts that hold up a build. Terminal bases, terminal units and communication couplers.

We buy ABB control hardware

AC500 modules, S800 I/O and Advant hardware all hold value. CM and CI communication parts in particular, because a plant still running the network cannot always get them new.

If you are decommissioning, do not scrap them, and keep couplers with the I/O stations they headed. See Sell To Us.

Related

ABB overview. ACS550 and ACS580, ACS880, S800 I/O and AF contactors.

For controllers from other brands see Siemens S7-1500, CompactLogix and Omron Sysmac.

Send us your order codes

Send the 1SAP number where you have it, since that is what identifies an XC version. Tell us whether you need the terminal base and terminal units as well as the modules. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with ABB Ltd. ABB, AC500, Automation Builder and Advant are trademarks of ABB Ltd. PROFINET and PROFIBUS are trademarks of PROFIBUS Nutzerorganisation. EtherCAT is a trademark of Beckhoff Automation. All trademarks, brand names and order codes are the property of their respective owners and are used here for identification purposes only.