This page explains the specification of wireless I/O.
■ Wireless I/O configuration
The basic configuration when using wireless I/O products is as follows.
Personal computer --- Ethernet --- Gateway (Master unit) --- 920 MHz --- Terminal (Slave unit)
■ How to acquire data from
a personal computer
The following two methods are available for acquiring data from a personal
computer.
•
Acquire
data stored in the parent machine
The flow acquiring the data stored in the master unit is as follows.
1.Send an instruction to
retrieve the saved data from the PC to the gateway.
2.The
gateway sends its own data to the PC.
Apart from the above flow, the slave unit periodically transmits data to
the master unit.
The data saved by the master unit is updated when data is received from
the slave unit.
The interval at which the slave unit transmits data to the master unit
can be changed by setting the slave unit.
Please change the setting with CONTEC Device Utility.
•
Acquire
data stored in slave unit
The flow acquiring the data stored in the slave unit is as follows.
1.Send an instruction to retrieve the slave unit data from the PC to the
master unit.
2.The master unit requests data from the slave unit.
3.The slave unit sends the current data to the master unit.
4.The master unit transmits the data acquired from the slave unit to the
PC.
■ Features of 920 MHz
When communicating at 920 MHz, the transmission time is restricted by
the transmission output/channel.
Please refer to the table below for transmission time limit.
Transmission output |
Channel No. |
Transmission time |
Limit |
|
Pause time after one transmission |
Max. sum total limit of transmission time per hour |
|||
1mW |
1 to 5 |
100ms less |
100ms |
3.5s |
1mW to 20mW |
62 to 77 |
50ms less |
50ms |
No limit |
33 to 61 |
200ms over 400ms less |
10 times the transmission time |
360s |
|
6ms over 200ms less |
2ms |
|||
6ms less |
No limit |
As there is a limit on 920 MHz, please be careful when accessing the
slave unit from the PC continuously when acquiring data of the slave unit.
When acquiring the saved data from the PC to the master unit, since there
is no access to the slave unit, the limit of 920 MHz is not a problem.
However, please note that the data stored in the master unit is not real
time information of the slave unit.