1747-L20A

The 1747-L20A SLC 500 Fixed Controller by Allen-Bradley is a 20 I/O-point controller in the SLC 500 fixed controller family with twelve 120V AC inputs and eight AC/DC relay outputs and requires a line power of 120-240 Volts. The controller features a 1K instruction programming memory with a 2-week capacitor life (and a 5-year lifespan) lithium battery-backed standard RAM with an EEPROM or UVPROM backup options. The 1747-L20A has a program scan time of 8ms per 1K instruction and a load-dependent hold-up time of 20-700ms between scans. This controller does not have a high-speed counter. The 1747-L20A offers a fuse protection of 1.25A at a voltage range of 120-240V AC and it has 5 status lights that indicate POWER, PC RUN, CPU FAULT, FORCED I/O, and BATTERY LOW statuses. The indicator’s circuit uses the 24 AWG wire size. The 1747-L20A uses a panel mount and supports two slot expansion racks for I/O expansion capability. It operates at 0-60 0C at 5-95% non-condensing relative humidity and it can withstand 30G and 2.5G of operational shock and vibration respectively at 10-500Hz.The 1747-L20A measures at 3.6 x 5.5 x 5.7 inches with a weight of nearly 0.4 pounds while the single slot has a dimension of 1.37 x 5.15 x 5.72 inches which weighs 2.5 pounds.

The Allen-Bradley 1747-L20A is a Programmable Logic Controller (PLC) from Allen-Bradley. It is part of the SLC 500 Fixed Style Hardware series that comes with embedded features, functioning as a full PLC assembly. This module comes with a capacitor-backed up Random Access Memory (RAM) with memory size of 1K instruction capacity. The 1747-L20A has a typical scan time of 8 milliseconds/1K and a bit execution speed of 4 microseconds.

This controller has a line voltage requirement of 120/240 Volts AC. It has embedded input and output channels - specifically, twelve (12) 120 Volt AC rated discrete input channels and eight (8) AC/DC relay outputs. Optionally, the embedded memory available to this device can be partnered with an EEPROM or UVPROM memory backup option. Similarly, an optional battery backup may be installed to retain the RAM memory contents longer as the embedded capacitor backup can only provide memory backup power of up to 30 days. With the use of a battery, up to 5 years of RAM backup can be achieved. Compatible battery for use with this controller is the 1747-BA.

The 1747-L20A is provided with LED indicators embedded within the module’s front panel. LED indicators include POWER, PC RUN, CPU FAULT, FORCED I/O, and BATTERY LOW. This controller has an embedded power supply with an operating voltage of 85-265 Volts AC @ 47-63 Hertz. It is also provided with a pre-installed fuse with a rating of 1.25 Amperes. The controller’s Power Hold-up time range is 20 milliseconds to 700 milliseconds and inrush current rating is 30 Amperes.