H-Series terminals have capability to send and receive serial
communication data outside of the terminals dedicated controller system
communications.
This ability has different applications and works in specific ways using
specific settings and programming.
1. The terminal can display a Terminal Window Object in graphic screens.
This terminal window can display received data in ASCII or Hex formats.
You can send ASCII characters from the terminal with the Set Value Button
Tool - in ASCII mode. The limitation here is that you will only send printable
characters - there is no way to send control characters, ex. Carriage
Return+Line Feed.
To use these functions the Controller / PLC Selection in Workstation Setup
should be set to ASCII Device. The Connection configuration determines the
physical port and parameters to use.
In the Terminal Window object the Read Variable should be set to RX
(receive).
In the Set Value Button Tool the Write Variable should be set to TX
(transmit). Set Value should be set to Character String. Enter the characters
you want to transmit directly in to the Set Value text box. Then when this
object is activated (touched) these characters will be sent.
2. Computer protocol Master and Slave capability.
With this functionality the terminal will in Slave Mode (Computer as
Master) respond to commands from a master to read and write internal variable
data. This is a defined protocol using ASCII characters. The protocol is
available upon request from Beijer Electronics.
With this functionality the terminal as a Master (Computer as Slave) will
poll a slave device using this same ASCII protocol.
When using this function the terminal allocates internal memory to act as
a slave device. The memory addresses W0 - W2047 for word devices, and B0 -
B1023 for bit devices are used. In Master mode these same addresses are use has
the valid device types and the terminal will generate the corresponding ASCII
commands to the slave device.
3. Use Macro or Ladder instructions to send and receive data.
4. H-Series terminals offer Modbus ASCII Slave and Modbus ASCII Master
communication drivers. Using this ASCII communication version of modbus would
be similar to using the Computer Protocol as described. But in this case the
Modbus Protocol is used. The terminal reveals its internal memory as Modbus
aware addresses.