Instructions

UM-0085-B09 DT80 Range User Manual Page 348
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Generic Serial Channel
The DT80’s Serial Channel can be used to connect to serial input and/or output devices such as a serial sensor, GPS
terminal, printer, barcode reader, display panel, PLC, or even to another DT80.
A serial channel
• can transmit programmable ‘prompt’ or ‘poll’ messages to serial devices and interpret their replies
• can respond to asynchronous incoming serial messages.
• can operate using the dedicated serial sensor port (terminal block connection on front panel, or the host
RS232 port (DE9 connector on side panel), or the USB port.
• may be included in schedules in the same way as any other DT80 channel. The channel name
1SERIAL is
used for the serial sensor port,
2SERIAL for the host port and 3SERIAL for the USB port
Connecting to and Configuring the Serial Port
Serial Sensor Port
Not applicable to DT81/ 82E
The serial sensor port is the one most commonly used for defining generic serial channels. It supports RS232, RS422
and RS485 connections.
The default function of this port is SERIAL so in that sense it is ready to use as a generic serial channel. You may,
however, need to configure the baud rate or other serial parameters to suit the device to which you are connecting.
For more details on setting up the port and the possible wiring configurations, see Serial Sensor Port (P196).
Host RS232 Port
Not applicable to DT8xM
The host RS232 port can also be used for controlling serial sensors.
Before a generic serial channel can be defined on this port, the port function must be set to
SERIAL, as follows:
PROFILE HOST_PORT FUNCTION=SERIAL
As with the serial sensor port, you may need to change the configured baud rate or other settings.
For more details on setting up the port and the possible wiring configurations, see Host RS-232 Port (P195).
USB Port
Not applicable to DT82
The USB port may be used in generic serial mode if you need to communicate with a PC application using a custom
serial protocol. As with the host port, this requires the port function to be set:
PROFILE USB_PORT FUNCTION=SERIAL
For more details, see USB Port (P187).
Serial Channel Commands
SERIAL Channel Type
Data flow into and out of the a serial channel is controlled by the Serial Channel commands. These commands provide
for
• formatting and management of output strings and prompts to be sent to the connected serial device.
• interpretation and parsing of input strings received from the connected device into channel variables
• general management of the Serial Channel
The general form of a Serial Channel command is:
n
SERIAL("control_string",options)
where:
• n is the serial port number (1 for the serial sensor port, 2 for the host port, 3 for the USB port).
• control_string is a string of commands that specify the required output and input actions of the Serial Channel.
See The Control String (P349).
• options are any other channel options that may be required