ControlLogix Selection Guide
It is no secret that Allen-Bradley has been a staple for PLCs when it comes to American manufacturing. One of their most common systems is the ControlLogix architecture, specifically the 1756 and the 5580 systems. Released back in 1997, the ControlLogix platform was introduced and was quite a step up from the previous PLC5 and the SLC while also introducing tag-based addressing for the first time. The earliest model of the ControlLogix family is the Logix 5550 with the L1 processor, though, they were quickly made obsolete by the faster L60 and L70 which offered higher speeds and more memory than the previous generation. Fast forwarding to 2015, the new ControlLogix 5580 was introduced, and it dominated the previous generation by providing up to 45 percent application capacity and a 1Gb Ethernet port to support I/O and applications with up to 256 axes of motion. With such a large jump in innovation and processing speeds, Allen-Bradley was planning on these controllers essentially future-proofing the systems that would adopt these latest processors. Following suit in 2018, the addition of the Compact GuardLogix 5580 and 5380 controllers was announced to an already plentiful controller lineup. To this day, the 5580 controllers remain a popular choice for consumers.
While the 5580 reigns supreme over the ControlLogix family, there are many other iterations of controllers to consider when choosing to upgrade or start a new system entirely.
Logix5550
The first iteration of the ControlLogix family is also generally the cheapest in the lineup, but that is for a good reason. The base controller comes standard with only 64KB of storage, however, that storage can be upgraded with the use of optional memory modules such as the 1756-M1 (512KB), 1756-M2 (1 MB), and the 1756-M3 (2 MB). The discontinued controller operates with a single RS232 port to communicate through ControlNet, DH+, DeviceNet, and EtherNet/IP networks. The controller operates with a battery whose replacement part number is 1756-BA1 for its non-volatile integrated Random-Access-Memory.
On the main face of the controller are diagnostic LED indicators that illuminate when a given status is present, such as RS232 communication or failure status. With it is a key that can be used to manually change the mode of the controller. The 1756-L1 can be installed in any ControlLogix chassis such as 1756-A4, 1756-A7, 1756-A10, 1756-A13, and 1756-A17, and it can be inserted into any slot. Because of this, multiple controllers may be used to communicate with each other on the same chassis. All of which is powered by the backplane from the main ControlLogix power supply.
This controller can control medium-scale processes as well as support IEC-61131-2 defined programming language standards such as Ladder, Function Block, Sequential Function Chart, and Statement List programming languages. Utilizing its integrated RS232 port, the controller provides an interface to programming devices, Human Machine Interface (HMI), Supervisory Control and Data Acquisition (SCADA), and other Visualization and Control systems. It also supports stand-alone and distributed I/O allocation with the use of ControlLogix I/O, Flex I/O, and POINT I/O modules.
Logix5560
The Logix5560 system is the first modernized system after the Logix5550. It proves to be quite faster than its previous model while remaining a good choice for budget-conscious consumers. These controllers come with an embedded RS-232 port for communication and can handle up to 250 controller connections. All L60 controllers come with 478 KB of I/O memory and user memory is dependent on the model being chosen.
The 1756-L6S Guard Logix controllers are also a new update to the more modern platform. These controllers take up two slots as they need a corresponding 1756-LSP Safety Partner beside it but function the same as the standard model with the addition of handling safety-related tasks and controlling safety I/O. The Safety Partner is automatically configured to its parent controller when installed. These safety modules also come with conformal coating to better protect them against harsh environments.
Another option for the Logix5560 is the 1756-L63XT extreme environment ControlLogix controller for those who need a controller for higher-temperature work environments. This controller functions just like the standard model but with the addition of widening the operating temperature scale from+32 to 140 degrees Fahrenheit (0 to +60 degrees Celsius), to -13 to +158 degrees Fahrenheit (-25 to +70 degrees Celsius). The ControlLogix chassis compatible with this controller are 1756-A4LXT, 1756-A5XT, 1756-A7LXT, and 1756-A7XT.
Connection Options
- DeviceNet
- ControlNet
- Remote I/O
- EtherNet/IP
- Data Highway Plus
- SynchLink
- SERCOS
- Third-party network and process devices
Serial Port Communication
- ASCII
- DF1 full/half-duplex
- DF1 radio modem
- DH-485
- Modbus via logic
Programming Languages
- Function Block Diagram
- Relay ladder
- Sequential function chart (SFC)
- Structured Text
Integrated Motion
- Analog options such as encoder input, LDT input, and SSI input
- SERCOS interface
- Integrated Motion through EtherNet/IP network
Controller Memory
- 1756-L61 - 2 MB
- 1756-L62 - 4 MB
- 1756-L63 - 8 MB
- 1756-L64 - 16 MB
- 1756-L65 - 32 MB
Controller Memory for GuardLogix
- 1756-L61S - 2 MB user / 1 MB safety
- 1756-L62S - 4 MB user / 1 MB safety
- 1756-L63S - 8 MB user / 3.75 MB safety
Logix5570
The ControlLogix 5570 series is the next leap forward for the Logix family and is quite a welcomed change. The L70 series now supports redundancy and Removal Insertion Under Power (RIUP). Performance has increased by as much as 2X over the last generation processor as well. With a new environmentally friendly design, the lithium-ion battery has been replaced with capacitor-based energy storage modules that can be removed and replaced. Each controller only takes up one spot in the chassis and multiple may be installed at the same time for full redundancy. The addition of a conformal coating has also been introduced when the 5570 had launched, usually denoted with a ‘K’ suffix at the end of the part number, as well as an Extended Temperature controller (Denoted with an XT instead). The ControlLogix-XT functions the same as the standard controller but can withstand temperatures from -13 to +158 degrees Fahrenheit (-25 to +70 degrees Celsius), as opposed to +32 to 140 degrees Fahrenheit (0 to +60 degrees Celsius) for the standard controllers. They also come with a conformal coating to extend the life of the controller as well as protect it from harsh and corrosive environments.
Each controller will ship with a 1GB SD card (1784-SD1) for optional nonvolatile memory storage. This can also be upgraded to 2GB if needed with the 1784-SD2. Each controller can support 32 to 1000 programs/tasks depending on the software used to configure them, as well as 128,000 digital I/O max, 4000 analog I/O max, and a total of 128,000 I/O max. For user memory, it depends on the controller chosen but the I/O memory is 0.98MB across the board.
Like the previous generation, the Logix5570 also released its own Guardlogix for the updated controllers. These safety modules perform similarly to the standard controller but use a red Safety Partner (1756-LSP) to perform its safety functions and to achieve up to SIL CL 3/PLe/ Cat. 4. These two cards paired together take up two slots on the available rack, but a major benefit is having both safety functions and standard together. The Safety Partner requires no additional user setup and is automatically configured into the system.
Connections
The embedded USB 2.0 (12MBps) port allows for communication through the following:
- DeviceNet
- ControlNet
- Remote I/O
- EtherNet/IP
- Data Highway Plus
- SynchLink
- SERCOS
- Third-party network and process devices
Programming Languages
- Function Block Diagram
- Relay ladder
- Sequential function chart (SFC)
- Structured Text
Integrated Motion
- Analog options such as encoder input, LDT input, and SSI input
- SERCOS interface
- Integrated Motion through EtherNet/IP network
Capacitor Energy Storage Modules
- 756-ESMCAP, 1756-ESMCA (removable, ships installed with every controller)
- 756-ESMNSE, 1756-ESMNS (removable, no residual WallClockTime power backup)
- 756-ESMNRM, 1756-ESMNRM (nonremovable, helps prevent USB connection and SD card use to help secure the controller)
Controller Memory
- 1756-L71/L71K - 2 MB
- 1756-L72/L72K - 4 MB
- 1756-L73/L73K - 8 MB
- 1756-L74/L74K - 16 MB
- 1756-L75/L75K - 32 MB
Controller Memory for GuardLogix
- 1756-L71S/L71SK - 2 MB user / 1 MB safety
- 1756-L72S/L72SK - 4 MB user / 2MB safety
- 1756-L73S/L73SK - 8 MB user / 4MB safety
Conformal Coating Certifications
- ANSI/ISA 71.04.2013 G3 Environment
- IEC 61086-3-1 Class 2
- IPC-CC-830
- MIL-I-46058C
- EN60068-2-52 salt mist test, severity level 3
Redundancy System
A redundancy system consists of two identical 1756 chassis to act as the main driver and a backup. To do this, certain criteria must be met, such as:
- An identical number of slots
- Identical modules within those same slots
- Either a 1756-RM2 or 1756-RM2XT module per chassis, once again, being identical
- Up to two ControlLogix 5570 or XT controllers
- Up to two 1756-RMCx cables
- A redundant ControlLogix 5570 controller connects the 1715 redundant I/O system through an EtherNet/IP network, all controlled by the 1756-EN2TR communication module
Redundancy System Features Not Supported
- All motion features
- Any SIL 3 Functions
Armor ControlLogix
Introduced with the Logix5570 family is the Armor ControlLogix controller. The 1756-L72EROM and 1756-L73EROM were built to combine either an L72 or L73 controller with two EtherNet/IP DLR-capable 1756-EN3TR communication modules all contained in an IP67 certified housing to be mounted to applicable machines. While this controller functions identically to the L72/L73, its energy storage modules are unable to be removed or replaced. Keeping with the trend of non-replaceable parts, the 1756-L72EROM is also protected by a soldered fuse which should protect it if the input range exceeds its 32V DC max as well as fire hazards from short circuits. One thing to also keep in mind is that these controllers do not support controller redundancy, meaning that a second controller can’t take over the tasks if the first were to fall into a faulted state. The 1756-L72EROM/L73EROM comes with a UL Type 4/4x enclosure, measures 9.4 x 11.5 x 6.5 inches, and weighs 15.50 lbs or 7.04 kg.
With the addition of the 1756-L72EROM/L73EROM in the ControlLogix family, Allen-Bradley had also introduced a safety variant, the 1756-L72EROMS/L73EROMS. This controller functions similarly to the non-safety model but with the addition of 2 MB of safety memory and the support for both standard and safety communication options through EtherNet/IP networks.
Logix5580
These processors are the most modern and up-to-date controllers in the lineup. With an all-new design, the addition of safety modules, extreme temperature controllers, powerful processors with over 5 to 20x faster operational speeds than the 5570 and 5560, and enhanced security (ISO 27001 certification), it is quite understandable why Allen-Bradley suggests first-time plant owners or those looking to upgrade start with the 5580 series first.
The Logix5580 series controllers now come with a 1Gb embedded ethernet port for high-speed communications, I/O, and motion control with the previously embedded USB 2.0 port. Unlike the previous models, these cards now ship out with a preinstalled 2GB SD card, which was considered an upgrade from the previous.
Released with the new generation of controllers is the GuardLogix 5580, able to achieve up to SIL 2/PLd (category 3) with a single controller and the use of the safety task and safety I/O. If a Safety Partner is paired with the original controller, it allows the safety integrity to reach SIL 3. This level of integration allows its safety memory to be read by logic and external devices, such as HMIs and other controllers, to minimize the need to condition safety memory for use elsewhere. This allows system-wide integration and the ability to display safety status on displays or marquees. These safety controllers are also available with a conformal coating, having the “SK” suffix at the end of the product number, and the “S” suffix without conformal coating.
ControlLogix 5580 Process Controllers have also been released with the latest generation of controllers. These are made specifically for hazardous workplaces and industries such as mining, metals, foods, oil, brewery, and more. These controllers focus on plantwide process control while also configured with the default process tasking model and dedicated PlantPAx process instructions for a much more efficient workflow. These controllers are designated with the “P” suffix at the end of the product number.
Like the previous generation, the 5580 also comes with their Extreme Temperature Controller (suffix of “EXT” on the part number) to widen the operating temperature scale from+32 to 140 oF (0 to +60oC), to -13 to +158oF (-25 to +70oC). These controllers come with a convection-cooled design, maintain all product certifications from the standard controller, and are tested to ANSI/ISA-S71.04-1985; class G3 standards. It is also recommended for customers who have previously used the LXT chassis to replace them with the K version of the chassis.
Connections
The embedded USB 2.0 (12MBps) port and dedicated Ethernet (1Gbps) port allow for communication through the following:
- DeviceNet
- ControlNet
- Remote I/O
- EtherNet/IP
- Data Highway Plus
- SynchLink
- SERCOS
- Third-party network and process devices
Network Connections per Network Module on the Local Chassis
- 128 EtherNet/IP; 64 TCP (1756-ENBT)
- 256 EtherNet/IP; 128 TCP (1756-EN2x)
- 528 EtherNet/IP; 512 TCP (1756-EN4TR)
- 40 ControlNet (1756-CNB/D, 1756-CNB/E)
- 100 ControlNet (1756-CN2/A)
- 128 ControlNet (1756-CN2/B)
Programming Languages
- Function Block Diagram
- Relay Ladder Logic
- Sequential Function Chart (SFC)
- Structured Text
Integrated Motion
- Analog options such as encoder input, LDT input, and SSI input
- SERCOS interface
- Integrated Motion through EtherNet/IP network
Controller Memory
- 1756-L81/L81K/L81EXT - 3 MB
- 1756-L82/L82K/L82EXT - 5 MB
- 1756-L83/L83K/L83EXT - 10 MB
- 1756-L84/L84K/L84EXT - 20 MB
- 1756-L85/L85K/L85EXT - 40 MB
Controller Memory for GuardLogix
- 1756-L81ES/L81ESK - 3 MB user / 1.5 MB safety
- 1756-L82ES /L82ESK - 5 MB user /2.5 MB safety
- 1756-L83ES /L83ESK - 10 MB user /5 MB safety
- 1756-L84ES /L84ESK - 20 MB user /6 MB safety
Conreoller Memory for Process Controllers
- 1756-L81EP - 3 MB
- 1756-L83EP - 10 MB
- 1756-L85EP - 40 MB
Conformal Coating Certifications
- ANSI/ISA 71.04.2013 G3 Environment
- IEC 61086-3-1 Class 2
- IPC-CC-830
- MIL-I-46058C
- EN60068-2-52 salt mist test, severity level 3
Redundancy Requirements
The 5580 High Availability System allows for quick switching between redundant systems in the case of loss of power, major fault, removal/insertion of any module, failure of a module, loss of an EtherNet/IP connection, and program-prompted switchover. To enable this feature, two identical 5580 systems need to contain these ControlLogix components:
- One ControlLogix power supply
- One ControlLogix 1756-RM2 redundancy module
- Redundancy modules link the redundant chassis pair to monitor events in each chassis and initiate system responses as required.
- At least one ControlLogix EtherNet/IP communication module
Redundancy Features Not Supported
- Any motion features
- Compact 5000 I/O
- DeviceNet, ControlNet, RIO, and Data Highway+ networks
- Event Tasks
- Firmware Supervisor
- IEC 62443-4-2 Security certification
- Input or consumed unicast connections
- License-based Source and Execution Protection
- Messaging to PLC-2, PLC-3, PLC-5, SLC, and other legacy controllers
- The embedded Gigabit Ethernet port of the controller
Conclusion
The ControlLogix is an extensive platform with many different controllers to choose from. It is important to conduct research as well as consulting guides such as these to help pick out the perfect setup for your needs. While there are many to choose from, Allen-Bradley recommends the 5580 system to be at the heart of your workflow. While that is an excellent choice, budget does play a major role in the selection of these controllers. It is up to the buyer to compromise on controller speeds for budget as these controllers all mostly follow the same specifications and process power. You wouldn’t be missing out on too much from a 5570 system compared to a 5580 system unless you want the flexibility of having the option of a single safety controller or process controllers.