The Allen-Bradley 1756-L1 is a ControlLogix 5550 controller. It can support up to 250 connections and weighs 0.28 kilograms or 10.0 ounces. This particular controller has a 64 Kilobytes user memory. Installing the 1756-L1 is installed directly into any slot available in the chassis and multiple controllers can be installed in any other slot within the same chassis. These controllers that belong to the same chassis, may communicate communicate with each other across the backplane as well as operate independently. The 1756-L1 has the capacity to communicate across DeviceNet, RS-232-C (DF1/DH-485 protocol), ControlNet, DH+, and EtherNet/IP networks. Note that it does not have a nonvolatile memory.
The 1756-L1 has a peak backplane current of 0.65 Amps at 5 Volts DC and 0.02 Amps at 24 Volts DC. It also has an average power dissipation of 3.3 Watts and an average thermal dissipation of 11.3 BTU/hour. The storage temperature of the 1756-L1 is from -40 to 85 Degrees Celsius, while its operating temperature ranges from 0 to 60 Degrees Celsius. It also has a noncondensing relative humidity of 5% to 95%. The storage shock of the 1756-L1 is 50 G peak for 11 milliseconds, while its operating shock is 30 G peak for 11 milliseconds. It also has a 10 to 500 Hertz vibration with a maximum peak acceleration of 2.0 G. If the 1756-L1 has a battery in need of replacement, you can only use the 1756-BA1, which is a 0.59g lithium battery. The programming cable compatible with the 1756-L1 are the category 3 serial cables 1756-CP3 and 1747-CP3.
The Allen-Bradley 1756-L1 is a Programmable Automation Controller (PAC) processor module that belongs to the ControlLogix product family. This processor belongs to one of the earlier versions of ControlLogix, the Logix 5550 category.

This module features an integrated RS232 communication port with 64KB user memory. It is also has a diagnostic front panel that reports the module’s state through embedded LED lights. delivered with a battery back-up for the integrated Random-Access Memory (RAM) however, this processor is not installed with a non-volatile memory. To install a non-volatile memory for this controller, appropriate memory modules are 1756-M1, 1756-M2 and 1756-M3 are the only compatible modules. Do not use other memory modules as this will result to module failure.

51402573-150	128229-01	T3481	IMFCS01
51401642-150	125720-01	T3310	NTAI06
51401635-150	125760-01	T8225	NTCL01
51403165-400	133442-01	T8151B	INNIS21
51401560-100	125840-01	T9432	3BHB002953R0108
MC-TAIH02	133396-01	T9110	NTCL01-A
MC-TAIL02	125800-01	T9402	NTDI01
MC-TAMR03	133323-01	T9451	SPDSO14
MC-TLPA02	135137-01	T9802	SPASO11
MC-TAOY22	125768-01	T9852	SPNIS21
MC-TAMT03	135489-01	T9300	SPDSI14
TC-IAH16I	140471-01	T9100	SPNPM22
TC-PRS021	3500/15	T9832	SPFEC12