Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 250)

Preface MicroLogix 1000 Programmable Controller User Manual
13–2
Types of Communication
Communication is the ability of a device to send data or status to other devices.
This capability typically falls into one of two categories: initiator (master) or
responder (slave). Each of these are described below:
Initiator (Master) Communication
Initiator products can begin communication processes, which includes requesting
information from other devices (reading) or sending information to other products
(writing). In addition, initiator products are usually capable of replying to other
devices when they make requests to read information. The Series C or later
MicroLogix 1000 discrete controllers and all MicroLogix 1000 analog controllers
are in this class.
Initiator products can begin communication processes with other initiator products
(peer-to-peer communication) or with responder (slave) products
(initiator-to-responder communication).
Responder (Slave) Communication
Responder products can only reply to other products. These devices are not capable
of initiating an exchange of data; they only reply to requests made from initiator
products. The Series A and B MicroLogix 1000 discrete controllers are in this class.