2
Terms and Definitions
 
2.  Terms and Definitions 
 
Term  Explanation and Definition 
Protocol macro  A protocol macro is a function that enables data to be sent and received 
with general-purpose external devices. 
This function can be realised by executing the protocol macro instruction 
(hereinafter referred to as PMCR instruction) in a CPU Unit's user program 
through storing procedures for sending and receiving data (protocols) in a 
Serial Communications Board or a Serial Communications Unit to 
exchange data with general-purpose external devices. 
Protocol  A unit of independent communication processing with a specific 
general-purpose device. A protocol includes procedures for sending and 
receiving data. A protocol consists of more than one sequence.   
Sequence  A unit of the independent communication processing which can be started 
by executing the PMCR instruction in a program. A sequence that is started 
by the instruction executes steps registered in its own sequence.   
Step  A unit to execute any one of the followings: message send processing, 
message receive processing, message send/receive processing, receive 
buffer clear, or step wait. Up to 15 steps can be set for per sequence.   
Send message  A communication frame (command) to send to general-purpose external 
devices. A send message is invoked by steps in the sequence and is sent 
to general-purpose external devices.   
Receive message  A communication frame (response) received from general-purpose 
external devices. A receive message is invoked by steps in the sequence 
and is compared with data received from general-purpose external 
devices.   
Receive matrix    A function to register and use some communication frames (responses) 
when more than one communication frame is expected to be received from 
general-purpose external devices. The receive processing can be 
executed according to registered communication frames by using this 
function.