User manual

Chapter 4 AMCI Module Addressing
4-1
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This chapter explains how to address a 1700 module in a PLC-5 programmable controller
system. If you are using a PLC-2 or PLC-3 system, contact AMCI if you need assistance.
When you configure your programmable controller system, a unique address is assigned to each slot of
each chassis in the system. The I/O Rack Number and I/O Group Number make up each address. A
block transfer address is further specified with a Module Slot Number.
Note that an I/O Chassis is not the same as an I/O Rack. An I/O Chassis is the physical
enclosure for the processor and I/O modules. An I/O Rack Number is part of a modules'
address in the system. Each I/O Chassis can have ¼ to 4 I/O Racks associated with it.
Definition of Terms
Block Transfer
The transfer of a block of data over the backplane in one scan. A Block Transfer Read
transmits data from an I/O module to the processor. A Block Transfer Write transmits data
from the processor to an I/O module. Up to sixty-four words can be transmitted per block
transfer.
Single Transfer
The transfer of a single unit (8, 16, or 32 bits) of data over the backplane. The transfer
occurs between I/O modules and the processors' Input or Output Image Tables. A 1731 or
1741 can be configured to transmit 16 or 32 bits of data with single transfers. Single transfers
occur automatically every I/O scan and can occur during a program scan with the use of
Immediate Input and Immediate Output Instructions.
I/O Rack
The number of I/O Racks, not the number of chassis, define the programmable controller
system. In PLC-5 systems the first I/O Rack is assigned the number 0. Each I/O Rack is
further divided into 8 I/O Groups.
When specifying a block transfer or single transfer address, all I/O Rack and
Group numbers are expressed in octal. (i.e. 00, 01, 02, ... 06, 07, 10, 11, ......)
I/O Group
An I/O Group consists of 16 input and 16 output bits. Eight I/O Groups, numbered 0
through 7, make up a single I/O Rack.
Slot Pair
Backplane slots of an I/O Chassis are numbered consecutively from zero starting at the
leftmost I/O slot. The processor slot is not numbered. A slot pair is two adjacent backplane
slots, the left of which is even numbered. Most A-B chassis have the slot numbers printed on
the backplane.
The module must be installed in a single slot pair to operate properly. See chapter 3, page
3-1,
Installing the Module
. The figures in this chapter show the module in a single slot pair.