1756-L71 | ControlLogix 2 MB Controller

The Allen-Bradley 1756-L71 is a ControlLogix Programmable Automation Controller. It has an available storage of 2 MB for user memory and an I/O memory of 0.98 MB. It also has an onboard 4-character alphanumeric display for easy monitoring of run-time and module information and controller diagnostics. It has an open-style enclosure and built-in One (1) 2.0 full-speed USB port available. The communication options that are available include DeviceNet, ControlNet, EtherNet/IP, Remote I/O Data Highway Plus, Third-party process and networks, and SynchLink. It also ships with a 1 GB non-volatile memory, but you can upgrade it to 2 GB with the 1784-SD2. It is recommended that the SD card be left installed in the controller. The 1756-L71 controller ships with three capacitor energy storage modules, two of which are removable. It has a current draw of 5 mA at 1.2 Volts DC and 800 mA at 5.1 Volts DC. The 1756-L71 controller also has a continuous isolation voltage of 30 Volts, a maximum power dissipation of 2.5 Watts, and a thermal dissipation of 8.5 BTU/hour. It has a maximum analog I/O, digital I/O, and a total I/O of 4,000, 128,000, as well as 128,000, respectively. It has an operating temperature range of 0 to 60 Degrees Celsius and a storage temperature range of -40 to 85 Degrees Celsius. Its maximum surrounding air temperature is 60 degrees Celsius and it has a noncondensing relative humidity of 5% to 95%. The controller has a vibration of 2G at 10 to 500 Hertz, an operating shock of 30G, and a non-operating shock of 50G that goes down to 45G when the SD card is installed. Other controllers may require the user to understand first PLC registers specifically Byte and Bit in order to start addressing program elements. With 1756-L71, the user simply needs to insert a program element and select the logical channel to where the I/O is physically wired. In other PLCs, the user may find the need to move a register to another to initiate conversion and processing just to get the analog data. This controller simply requires the user to find the logical channel where the I/O signal is physically terminated.

This controller is part of the modern Logix controller platform which are classified as Programmable Automation Controller (PAC). This PAC product range is ideally used for medium to large automation requirements, particularly compatible in control requirements of Factory and Process Automation industries.

The 1756-L71 mainly feature 2MB user memory and 0.98 MB I/O memory. It is also shipped with a 1784-SD1 Secure Digital (SD) memory card amounting to 1 GB non-volatile memory which can be upgraded to 2GB by replacing with 1784-SD2 card. This controller can handle up to 128,000 Discrete input and output signals and 4000 Analog Input and output signals as well.

Being a modern controller, the 1756-L71 does not use battery to retain the contents of the Random Access Memory (RAM) or volatile memory instead, it is equipped with energy storage modules with catalog number 756-ESMCAP or 1756-ESMCAPK. This energy storage module is of removable type which is capacitor based.

For industrial communication, the 1756-L71 supports installation of communication adapters. Other supported communication protocols by the 1756-L71 are EtherNet/IP, ControlNet, DeviceNet, Data Highway Plus, Remote I/O, SynchLink, Third-party process and device networks.

This controller is a chassis based controller. Which means a specific ControlLogix chassis must be installed in order to mount the module. Compatible chassis include 1756-A4, 1756-A4K, 1756-A7, 1756-A7K, 1756-A10, 1756-A10K, 1756-A13, 1756-A13K,1756-A17, 1756-A17 K.