Rockwell Automation 1791-XXXX ANALOG BLOCK I/O - Manual (Page 8)

Chapter
1
1-1
Introducing Block I/O
In this chapter, you will learn what analog block I/O is, its features, and
how it functions.
Block I/O consists of small, self-contained remote I/O devices complete
with power supply, programmable controller interface, input/output
connections and signal conditioning circuitry. Table 1.A is a list of block
I/O modules covered in this publication.
Table 1.A
Types of Block I/O
Catalog Number Power Supply Voltage Inputs Outputs Description
1791ĆN4V2 120V ac 4 2 analog - 4 input, 2 voltage output
1791ĆN4C2 120V ac 4 2 analog - 4 input, 2 current output
1791ĆNDV 24V dc 4 2 analog - 4 input, 2 voltage output
1791ĆNDC 24V dc 4 2 analog - 4 input, 2 current output
The analog blocks are compatible with PLC-2

, PLC-3

, PLC-5/250

and
PLC-5

family programmable controllers, and the SLC

5/02 (or greater)
modular controllers. Refer to the table below for information on using
block I/O with various Allen-Bradley programmable controllers.
If You are Using: You must use:
PLCĆ2 family programmable controller
1771ĆSN subĆI/O scanner or
1772ĆSD and ĆSD2 remote I/O scanners
PLCĆ3 family programmable controller
PLCĆ5 family programmable controller
Block attaches directly to controller
PLCĆ5/250 programmable controller
y
SLC 500 programmable controller 1747ĆSN remote I/O scanner
The analog blocks communicate via block transfer or discrete transfer with
any Allen-Bradley programmable controller that connects to the remote
I/O network. The analog blocks communicate with SLC family controllers
using discrete transfer.
Each analog block has four independent inputs, which can be configured as
either all voltage inputs or all current inputs. The block contains a 24V dc
current limited voltage source for accommodating loop-powered current
transducer inputs.
Chapter Objectives
General Description