Chapter 8. Communication Functions
8-83
8.4 No Protocol Communication
8.4.1 Introduction
No Protocol Communication is useful when communication between GM7U main unit and other kind of devices with user
defined protocol is impossible. User defined protocol is very convenient when there are enough interval between frames or a
kind of frame is less than 16. But, when the kind of frame is greater than 16 or frames are continued without interval, user
defined protocol is not available. When the frames are more than 16, they can’t be registered in parameter area; therefore
GM7U can’t transfer these frames.
Sending frame no.0
Receiving frame no.1
:
Sending frame no.15
Also, if there are no intervals between frames, GM7U can’t find end of frame.
To overcome these defects of user defined protocol, GM7U provide ‘No Protocol Communication ’.
In the No Protocol Communication, frames are designated by commands, not by parameter setting. So maximum of 128
frames can be designated when using this communication mode. This section explains No Protocol Communication setting
& usage.
1) Sending data
• Command: DSND
• Sends stored data in designated device at the rising edge of input condition.
• Data and the number of character must be stored in designated device before they are sent.
2) Receiving data
• Command: DRCV
• Saves received data to pre-defined receiving devices when designated ending condition is occurs.
• The ending condition can be designated by following two methods.
- By received number of character.
- By designated last byte. It is useful when there is no interval between received frames.
No Protocol Communication supports HEX communication. In ASCII communication, h31323334 is saved in the received device
when the received device is h1234. To send data ABCD, save h41424344 in the send device and use the DRCV function block.
To convert the HEX value to ASCII value, use ASC function block, for ASCII to HEX, use HEX function block. This chapter describes
about No Protocol Communication.
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