IN-E-HyFlex-V4_10
Rotronic AG
Bassersdorf, Switzerland
Document code
Unit
Instruction Manual
Document Type
HygroFlex transmitter version 4: instruction
manual
Document title
Page
53
of 61
© 2006; Rotronic AG IN-E-HyFlex-V2_10.doc
16 ASCII communications protocol
The HygroFlex transmitter is compatible with two different communications protocols: ASCII and
HW4. When interrogated, the HygroFlex automatically recognizes which protocol is being used and
does not require a manual configuration of its serial settings.
The following describes the ASCII communications protocol. This information is provided for users
who for any reason are planning on using their own software.
Connections with a PC COM port
The exchange of data requires 3 wires: TXD (transmit), RXD (receive) and SG (signal ground).
When the ROTRONIC device requires power from the COM port (example: MOK-WIN probe
calibration cable), the RTS and DTR wires are also used.
Settings required by the ASCII communications protocol
The ASCII communications protocol uses only 7-bit ASCII characters (ASCII 32 to 127).
Parity :
even
Data bits
: 7
Stop bits
: 1
Use these settings to configure a third-party software used to communicate with the HygroFlex
(see ASCII commands provided in this manual). Also use these settings to configure a device
server (connection of a serial device to an Ethernet LAN). Set flow control to none and, if
necessary, force incoming data to 7-bit ASCII.
Models with optional Ethernet interface
: the internal Ethernet module should be re-configured to
use these settings. Detailed instructions are provided separately in document
IN-E-TCPIP-
Conf_10.doc
(also available in PDF format).
Baud rate
Compatibility with the ASCII protocol requires the 19200 Baud rate (factory default).
IMPORTANT: Please note that all devices connected to an RS-485 multi-drop should use the same
baud rate in order to communicate.
Data integrity
-
7-bit characters are sent with a parity bit. 8-bit characters are sent without parity bit.
-
Strings (made of 7-bit characters) can be sent with or without checksum at the end of the string.
When the checksum is not known – for example: when sending a command - the checksum is
replaced by the } character at the end of the string.
