ControlLogix Controllers vs Guardlogix Controllers

Allen Bradley’s controllers family, Logix 5000, features a wide range of controllers such as ControlLogix controllers, GuardLogix controllers, Armor ControlLogix controllers, Armor GuardLogix controllers, CompactLogix controllers, and Compact GuardLogix controllers. Each of these controllers families has unique features that can be helpful to decide a suitable controller while designing a control system for a particular application.  

In this guide, we will only focus on ControlLogix controllers and GuardLogix controllers. We will go through the features of these controllers as well as make comparisons between them. In the first section of this guide, we will discuss the key differences between the features offered by ControlLogix and GuardLogix controllers. The other section will cover the same features offered by both controllers. 

Differences and Safety Features

Allen Bradley 1756 ControlLogix controllers family offers a wide range of scalable controller solutions. You have the independence to connect multiple controllers in the same ControlLogix I/O chassis that allows you to address them multiple I/O points. 

GuardLogix controller is basically a ControlLogix controller that offers the additional feature of safety. Hence, It is a dual controller solution; safety and standard. That saves you from the hassle of worrying about a safety partner for the application. We will discuss this in more detail in this guide.

Safety Partner: 

GuardLogix Controllers comes with a compatible safety partner controller. This safety controller does not need user setup as it can configure itself automatically. That’s why it is allowed to be used in applications that require safety.  Using safety partners in the GuardLogix Controllers allows you to achieve the safety integrity of  SIL 3 and PLe/Cat.4.  

Once the safety system is set (whether SIL 3 or PLe/Cat.4), the safety memory gets locked. After this, a modification in safety logic is not possible, and all safety-related tasks will be operated with SIL integrity. But, GuardLogix Controllers’s standard side (primary controller) works like ControlLogix Controllers. As a result, online editing (updating), forcing, and other similar actions are all permitted. 

The primary controller is in control of configuring the safety partner. The user application only has to be downloaded once to the primary controller. The primary controller is used to control the operation mode of the safety partner. On the other hand, ControlLogix Controllers does not offer this safety feature.  

Controller Tasks: 

Both ControlLogix and GuardLogix Controllers can handle a total of 32 tasks. In ControlLogix Controllers, all tasks are standard. However, the one task in GuuardLogic Controllers is the safety task with SIL 3 safety integrity, and the remaining 31 tasks are standard. 

Both controllers allow only one continuous task. While other tasks run periodically or event-wise. Both controllers allow 15 priority levels. Whether to use event, periodic or continuous task type, highly depends on the application for which the control system is being designed. 

The safety task is a priority task selectable by the user and watchdog that runs on a periodic basis. For most circumstances, the GuardLogix Controller’s top priority is the safety task, and the user-defined program watchdog should be configured to handle variations in the safety task’s operation. 

User Memory:

GuardLogix Controllers offer safety memory along with the primary memory that is the same as the corresponding ControlLogix Controller.  

ControlLogix 5580 controllers offer user memory of 3 megabytes to 40 megabytes, whereas, GuardLogix 5580 controllers, along with this user memory of 3 to 20 megabytes, offer 1.5 to 6 megabytes of safety memory. For example, 1756-L81E has a user memory of 3 megabytes. On the other hand, 1756-L81ES has 1.5 megabytes of safety memory along with 3 megabytes of user memory. 

1756-L7 and 1756-L6 ControlLogix controllers have user memory ranging from 2 megabytes to 32 megabytes. However, 1756-L7S and 1756-L6S  GuardLogix controllers, in addition to the 2 to 8 megabytes of user memory, offer 1 to 4 megabytes of safety memory. For example, 1756-L72 contains a user memory of 4 megabytes. On the other hand, 1756-L72S offers 2 megabytes of safety memory and 4 megabytes of user memory.  

Standard logical and peripheral devices, such as HMIs and perhaps other controllers, are used in GuardLogix controllers to read safety memory, which reduces the requirement to condition it for use elsewhere. 

Safety Communication Options:

Only GuardLogix controllers offer the following safety communication options: 

• EtherNet/IP Network: It allows the peer to peer safety communication among GuardLogix Controllers. 
• DeviceNet Safety Network: It allows the 1756 GuardLogix controllers to control and interchange safety data through CIP Safety Input /output modules. 
• ControlNet Network: The GuardLogix controller may create and receive safety tags across ControlNet networks towards other GuardLogix controllers or distant CIP Safety Input /Output networks. 

The ladder diagram is supported by the GuardLogix Controllers for the safety tasks.  

Controller Redundancy:

ControlLogix controllers have a feature of controller redundancy. ControlLogix redundancy allows you to provide redundancy between two controller chassis without having to do any more programming. It is intended to be regarded as a unified system or single system, and any devices connected via a ControlNet /EtherNet/IP network will see it as such.  

The primary controller chassis automatically detects what data changes throughout its scan and delivers that info to the secondary controller, ensuring that it is ready to claim control without even any output modifications. There’s no need to program messages or define which data to send. This feature reduces the need for engineers to spend time managing the redundancy system. 

This feature is not supported in GuardLogix Controllers. However, the safety partner in these controllers acts as a coprocessor and adds redundancy to the system’s safety operations. 

Similarities and Standard Features

Built-in Communication Ports:

ControlLogix 5570 controllers and GuardLogix 1756-L7S controllers feature only one built-in communication interface, which is a USB port. This port, which is of type 2.0 and has a top speed of 12 Mbps, is solely used for short-term programming purposes, firmware upgrades, configuration, and online editing.

One RS-232 serial port is available on ControlLogix 5560 controllers and GuardLogix 1756-L6S controllers. This serial port allows communication protocols such as DF1 – half-duplex, DF1 – full Duplex, DH – 485, DF1 – radio modem, ASCII interface for duplex operation, and Modbus via logic.

Two communication ports are integrated into ControlLogix 5580 controllers and GuardLogix 5580 controllers. One is a USB port of type 2.0 and is only used for functions including short-term programming purposes, firmware upgrades, configuration, and online editing. The other option is an integrated Ethernet port that allows an ethernet connection with speeds of 10/100/1000 Mbps.

Standard Communication Options:

All ControlLogix and GuardLogix controllers from Logix 5000 family have the following standard communication options.

• EtherNet /IP that allows real-time I/O messaging 
• ControlNet that offers merged functionality of I/O and peer to peer networking 
• DeviceNet communication that is preferred to integrate simple to complex applications 
• Data Highway Plus communication to allow messages among DH+ network devices 
• Remote Input /output 
• SynchLink 

Memory:

Besides the user and safety memory, ControlLogix and GuardLogix Controllers have other memory options such as I/O memory and non-volatile memory. 

The ControlLogix 5570 and 1756-L7S GuardLogix controllers contain 0.98MB of allocated input/output memory. The ControlLogix 5560 and GuardLogix 1756-L6S controllers feature 478 KB of allocated input/output (I/O) memory. ControlLogix 5580 controllers and GuardLogix 5580 controllers have no allocated I/O memory; instead, memory is allocated as needed. 

Both controller families can support SD (Secure Digital) cards as non-volatile memory, allowing data to be tagged on the controllers or user programs to be saved indefinitely. ControlLogix 5580 and GuardLogix 5580 controllers support a 2 GB SSD card. ControlLogix 5570 snd 1756-L7S GuardLogix controllers support a 1GB and 2 GB SSD card. ControlLogix 5560 and 1756-L6 GuardLogix Controllers support a 128 MB SSD card. 

Nodes Limit and Permissible Controllers Connection:

60 to 300 Ethernet /IP nodes can be supported by ControlLogix 5580 controllers. However, the corresponding GuardLogix 5580 controllers can support 100 to 300 IP nodes. For example, ControlLogix controllers 1756-L82E supports 80 nodes with version 29 and 165 nodes with version 30 or later of Studio5000 Logix Designer application. Whereas, 1756-L82ES offers a node limit of 165.

1756-L7/ 1756-L6 ControlLogix controllers, 1756-L7S, and 1756-L6S GuardLogix controllers do not have integrated EtherNet port; that’s why there is no node limit associated with these controllers.

The ControlLogix 5570 controllers and 1756-L7S GuardLogix controllers allow a max of 500 controller connections. The ControlLogix 5560 controllers and 1756-L6S GuardLogix controllers support a max of 250 controller connections.

Energy Storage Modules and Batteries:

ControlLogix 5580 controller and GuardLogix 5580 controllers come with energy storage modules that can not be removed. ControlLogix 5570 and 1756-L7S ControlLogix controllers can support removable as well as non-removable energy storage modules.

The feature of energy storage was introduced in 1756-L7x and 1756-L8x ControlLogix and GuardLogix controllers.

ControlLogix 5560 controllers and 1756-L6S GuardLogix controllers are shipped with a lithium battery. As discussed earlier, these controllers come with non-volatile memory. The controller may be operated without even a battery since it has nonvolatile memory. Current tag data stays in the same condition as it was when the nonvolatile memory was stored if you don’t use a battery.

Network Connections:

ControlLogix 5580 Controllers and GuardLogix 5580 controllers have integrated EtherNet/IP port with a specific node limit as mentioned under the head ‘Nodes Limit and Permissible Controllers Connection’. This node limit is a permissible network connection in these controllers.  

Depending on the communication module attached to the controllers, network connections capacity is offered. ControlNet module 1756-CN2/A allows 100 network connections in 1756 – L8, L7, L6, L8S, L7S & L6S ControlLogix, and GuardLogix controllers. 1756-CNB/D and 1756-CNB/E, both ControlNet modules permit 40 connections in 1756 – L8, L7, L6, L8S, L7S & L6S ControlLogix, and GuardLogix controllers. 1756-CN2/B ControlNet allows 128 network connections in ControlLogix and GuardLogix controllers. All these ControlNet modules allow a communication rate of 5 Mbps.  

Installation of EtherNet/ IP network modules 1756-EN2x and 1756-ENBT to these controllers can allow Logix connections of 256 and 128, respectively. These modules also allow 128 TCP/IP and 64 TCP/IP connections to these controllers. 

Electrical Specifications:

ControlLogix 5580 controllers and GuardLogix 5580 controllers draw 5.0 milliamps and 1.20 amps from a power source at 1.2 volts direct current and 5.1 volts, respectively. They dissipate 6.2 watts of electrical power and generate 21.2 BTU/ hr of thermal heat.  

ControlLogix 5570 controller and 1756-L7S GuardLogix controllers draw 5.0 milliamps and 800 milliamps from a power supply at 1.2 V DC and 5.1 V DC, respectively. They disperse 2.5 watts of electrical power and yield 8.5 BTU/ hr of thermal energy.  

ControlLogix 5560 controller and 1756-L6S GuardLogix controllers require 1200.0 milliamps and 14 milliamps from a power source at 5.1 V DC and 24 V DC, respectively. They produce 11.9 BTU/hr of heat energy while dissipating 3.5 watts of electrical power.

Miscellaneous Features:

ControlLogix 5580 controllers, ControlLogix 5570 controllers, ControlLogix 5560 controllers, GuardLogix 5580 controllers, 1756-L7S GuardLogix controllers, and 1756-L7S GuardLogix controllers  have a max digital I/O capacity of 128,000, analog I/O capacity of 4000, and total I/O capacity of 128,000.  

ControlLogix 5580 controllers and GuardLogix 5580 controllers can fully support attributes of integrated motion. They support 256 motion axes on the EtherNet/ IP network. ControlLogix 5570 /5560 controllers and 1756-L7S /L6S GuardLogix controllers offer 128 motion axis. They support integrated motion features with analog options, EtherNet/IP network, and SERCOS interface. 

Multiple programming languages are allowed to use in all ControlLogix and GuardLogix controllers. The first one is Ladder Logic Diagram, which is a commonly used flexible language for boolean and complex logical operations. Another one is a graphical language, function block diagram, which is best suited for PID control (loop control) ad drive control, etc. Another graphical language is the sequential function chart that is preferred for motion control, simultaneous operations and batch process, etc. The high-level language is structured text for complex operations. 

All these controllers can function well in the temperature range of 0 degrees Celsius to 60 degrees Celsius. The non-operating temperature range for ControlLogix and GuardLogix controllers is -40 degrees Celsius to 85 degrees Celsius. For more information or to discuss which equipment might be best for your application, please visit our website here, or contact us at [email protected] or 1-919-535-3180. 

This entry was posted on February 14th, 2022 and is filed under Allen-Bradley, Hardware Comparison, Uncategorized. Both comments and pings are currently closed.