MembersPage/GasEngine/AutoDerivativeSmallGasEngine/ModbusSlave (2018-02-09 14:13:49)

Subpage of MembersPage/GasEngine/AutoDerivativeSmallGasEngine

Special fw built with modbus slave on 2nd RS232


2nd RS232 for CRC protected special commands, voltage measured from pin5 (GND) base

1st RS232TX (EC18/14) (female DSUB9/3)

1st RS232RX (EC18/15) (female DSUB9/2)

GND

2nd RS232TX (EC18/6) (female DSUB9/2)

2nd RS232RX (EC18/12) (female DSUB9/3)

GND EC18/17 (DSUB9/5)

Examples:

(02) 06 00 XX VV 00 (CRC CRC)

XX table:

Read (subset or all) runtime vars command

Standard modbus command 03 (Read holding registers) example:

(02) 03 00 XX 00 LL (CRC) XX = index, LL = length in words (max 38)

  • response is 2*LL bytes (as in modbus standard), from 2*XX byteoffset. The full set of runtime variables can be read in 1 or multiple queries.

Register/Address for reading

Eg XX=07 and LL=01 gives the RPM value (byteoffset=14) in big endian format 0..25500 RPM: command with CRC: [02 03 00 07 00 01 35 F8]

Byte offsets (for some important values):

See <VT installdir> /config/vemsTune-v3-1.2.23.ini

Other:

- EGT1, EGT2

- worst knock value

- relative knock values 0..7

- errors, trigger error (hibák)

- individual power (gyújtás kihagyás)