The Allen-Bradley 1747-L551 Processor Hardware is integrated with a
program memory size of 16 KB. It is high-performance controller,
capable of controlling up to 4096 input and output points. This
module supports online and offline programming such as runtime
editing. The Allen-Bradley 1747-L551 has channel-to-channel, remote
I/O, and DeviceNet pass-thru features. This module also has a
built-in real-time clock and calendar. This module comes with a
Ethernet port for network connection and RS232 port for
peer-to-peer communication. The RS-232 channel supports DF1 full
duplex, DF1 half-duplex master and a DF1 radio modem. The
integrated Ethernet port supports a built-in 10/100 Base-T Ethernet
channel for supporting SNMP, BOOTP, extended messaging
capabilities, and high-speed communication. For programming, it
includes advanced math instructions and various additional
instructions. It also includes support for indirect addressing. The
SLC 505 has a typical Program Scan Time per Keyword of 0.9
milliseconds and typical I/O scan time of 0.225 milliseconds.
This module has a dielectric withstand of 150 Volts AC based on the
UL 508, CSA C22.2 No. 142 Standards. The operating vibration of the
1747-L551 is 2.5G at 5 to 2000 Hertz. The non-operating vibration
is 5G at 5 to 2000 Hertz. The isolation between the communication
circuits of this module is around 500 Volts DC. The isolation
between the backplane and the I/O of this module is 1500 Volts AC.
Before installing and uninstalling I/O devices, disconnect the
power from the controller and the other power sources that serve
the I/O device. The operating temperature of the 1747-L551 is 32 to
140 degrees Fahrenheit, and the storage temperature is around -40
to 185 degrees Fahrenheit. The Allen-Bradley 1747-L551 has an
operating shock of 30G (3 pulses, 11 milliseconds). The
nonoperating shock is 50G (3 pulses, 11 milliseconds). The relative
humidity is from 5-95% non-condensing. This module has a scan time
typically around 0.9 milliseconds/K. Its LED light will indicate
several different situations, including when the module is running,
when the CPU experiences a fault, when the battery is low, an I/O
is being forced, or when its Ethernet/RS-232 ports are active.
This processor is exclusively installed in Slot Zero (0) of the SLC
500 chassis. It supports Remote I/O implementation with the use of
a communication adapter installed at the chassis where the CPU is
located, and scanner modules installed at the chassis where the
Remote I/O modules are described. Supported communication protocols
are Ethernet, Remote I/O (RIO), DH485 and Data Highway Plus (DH+).
It must be cleared that Remote I/O technology is different from
Remote I/O (RIO) protocol. Remote I/) technology or sometimes
referred to as Distributed I/O is the technology that allows
installation of Input and Output modules away from the processor,
through a remote chassis with the CPU still treating the remote
modules as part of the local chassis. Remote I/O or most commonly
referred to as RIO is a proprietary protocol by Allen-Bradley.
This processor, similar to other processors is designed with the
capability of being communicated to computer-based control systems
such as Human Machine Interface (HMI) and Supervisory Control and
Data Acquisition (SCADA).
