OG_MU-4-434_v10e Circuit Design, Inc.
60
OPERATION GUIDE
Chapter 6 How to Develop a Program
Control of the MU-4 is performed by issuing commands and processing the subsequent response (including the data
receive at the target station).
The MU-4 has 3 modes, however the only mode required for making practical applications is the command mode.
This chapter explains the items necessary for developing a user program, focusing on the command mode.
The purpose of the MU-4 is to provide the basic components for communication in order to enable various types of
equipment to use radio.
For this reason it is necessary to build communication protocols (ARQ, MCA and so on) into the user application in
accordance with the particular application.
*ARQ: Automation Repeat request MCA: Multi-Channel Access
6.1 Outline of User Processes
The outline of how the user controls the MU-4 is explained using one-way communication as an example.
When using the MU-4 to transmit data, it is first necessary to perform various initial settings. When an MU-4 setting
command is issued, a command response corresponding to the command is always returned from the MU-4.
Process the command response as necessary. In addition, when data is received from the source station, a data
receive is output from the target station, so perform receiving process according to its data size.
In order for the target station to receive the data transmitted from the source station, it is necessary to set the link
parameters. When the data transmission command is issued, the link parameters are placed in the actual wireless
data frame and are processed appropriately by each station. Since the data is not addressed to it, the relay station
simply relays the data unconditionally. If there is no data error, it is output to the user controller by the target station
as the data receive.
In order to ensure reliable transmission of data, use the data transmission command that has an ACK response.
In addition, when the status of radio waves in the channel being used is poor, it is possible to change the channel of
each station using the relay function with an extended command.
There is also a convenient data transmissoin command for outputting the same user data from the relay stations as
well.
Includes link parameters
*Issuing @DT commands:
1. Method of sending data using relay stations
-Issue the DT command after setting the route register information
-Enter the DT command directly in the route information
2. When relay stations are not used(1:1 communication)
-Enter the EI of the target station in the DI and issue the DT command.
Disable route information.
3. Set only one target station EI in the route information and issue the DT command.
*DR response receive processing:
1. The route information and EI in the frame are compared
2. The UI and GI of the frame are compared at the same time
3. Received data is only output if there are no frame errors and the Link IDs
match
User
controller
Radio frame structure
User
controller
Send data
Link parameter settings
Receive data
Link parameter settings
Response processing
Response processing
Note:
*Set the same UI and GI for all equipment in the user system group
*UI=User ID, GI=Group ID, EI=Equipment ID, DI=Destination ID, RT=Route information
*Sync=Synchronized signal, FCS=Frame check sequence
Target
station
Relay
station
Link Parameter
UI,GI,DI,RT
User data
FCS
Sync.
Data that reaches the relay stations unconditionally is
relayed to the next stage (EI settings required)
Relay
station
Source
station
