5
Technical Information
RS
232/RS 485 Communication Description
76/90
MS40+ Single Stage Rotary Vane Pumps User Manual / 87-901-008-01 (
E)
Communication Protocol
The communication protocol is a MASTER/SLAVE type where:
Host = MASTER
Controller = SLAVE
The communication is performed in the following way:
1.
the host (MASTER) send a M CRC to the controller
(SLAVE);
2.
the controller answer with an CRC to the host.
The MESSAGE is a string with the following format:
<STX>+<ADDR>+<WIN>+<COM>+<DATA>+<ETX>+<CRC>
Where:
NOTE
When a data is indicated between two quotes (‘...’) it means that the indicated
data is the corresponding ASCII character.
<STX> (Start of transmission) = 0x02
<ADDR> (Unit address) = 0x80 (for RS 232)
<ADDR> (Unit address) = 0x80 + device number (0 to 31)
(for RS 485)
<WIN> (Window) = a string of 3 numeric character indicating the
window number (from ‘000’ to ‘999’); for the meaning of each
window see the relevant paragraph.
<COM> (Command) = 0x30 to read the window, 0x31 to write into
the window
<DATA> = an alphanumeric ASCII string with the data to be
written into the window. In case of a reading command this field
is not present.
The field length is variable according to the data type as per the
following table:
