The serial interface information is sent as a character string that is closed with a RETURN (CR) for
synchronization. Within the string there are three used data words each having four characters
(Bytes). The complete data string therefore comprises 3 x 4 + 1 characters.
Each part character string of the data word is the hexadecimal code equivalent of the 16 bit integer
expression of the used data. Only upper case characters "0" to "9" and "A" to "F" are permitted. Each
character is transmitted with 8 bits represented by ASCII code. Each part of the string contains four
characters and if necessary a leading zero is used.
The value range of the used information is depicted in a different manner to the value range of the
internal data format (16 bit integer). To differentiate, the values and the bit coded status information
are relative or absolute, signed or unsigned and limited or unlimited.
Type Signed Limiting Example Value range Form
Relative Not signed
Limited Set point,
Setting range
(0..100)% (0000..FFFF)
Relative Not signed Unlimited Effective value (0..200)% (0000..FFFF)
Relative Signed Limited Regulation range,
phase position
(-100..100)% (8000..7FFF)
Absolute Not signed Limited Time, frequency Individual Individually
scaled
bit Status True, false (0000..FFFF)
The character string is controlled by the RETURN’s for the correct length and existence and so invalid
information is disregarded. The watchdog switches the set point to zero if non valid information is
received.
! The string to be sent must be repeated continuously !
Example:
Adjust set point to 70 % and enable ON.
RS 232 Character String: "B33200000004"+CR
3.0 Serial Interface Modes
When serial inteface communication is used there are two basic operating modes:-
Normal operation:
Control of the frequency controller in a production process.
In this mode the set point and control signals (On/Off) are transmitted..
Parameter operation:
Setting of the frequency controller to the required operating mode and limits.
In a special mode the parameters and their addresses are sent to the
frequency controller and are received back as confirmation
In parameter mode, specific controller values such as frequency, soft start,
time delays, contactor etc. are adjusted.
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