Feb 21 2013code from the RS232 version what you see here is TOP: arduino 2009 no CPU (FTDI to program/communicate with: MIDDLE: DIY duino with 3 wires D2 -- D3 ; D3 -- D2; GND ( RS485 comes later) to: BOTTOM: arduino uno both connected to computer by USB ( and powered), + only one to arduino Terminal, + other port by hterm First work on that project to move it ( from "0022" ) to "ARDUINO 1.0" (new)SoftwareSerial i like to test some more features for a multi drop link, a init set up of a slave in EEPROM start with the slave add. Now there is in the (master) main menu a feature to check for a uninit slave ( like a slave with a add '0' ), you can give a new slave add ( ! should not exist ! ), what is saved at the slaves EEPROM; so one by one you can add new slaves to a link and init its add by master menu ( a common working style i have seen at HART instruments multidrop links ) one byte for each configurable DIO ( 4 .. 12 ) init as input, input pullup, output, PWM. even this can be changed from master online ( into slave EEPROM ) it is valid only after slave reset/reboot ( automatic ) this version SLAVE8 will be now be renamed as REMOTE_I/O ( fully configurable and operable from master) A new version now includes PID control for input use A0, for output use D9 PWM operation and loop tuning from master tuning and setpoint, mode.. in slave EEPROM, so powerfail, linkfail no problem so installing a new controller requires a link with a master, to setup slave add, I/O and optional PID control with tuning and setpoint and mode. After that the new controller could be stand alone. master menu operation of control loop is basic, finally there will be a processing appl.
now working again on hardware, i first need the ARDUINO PROTO SHIELD with the RS485 link hardware, because its a older shield i leave some unused options on it. MASTER SHIELD and for the DIY SLAVE here the SLAVE SHIELD and the code of the version 1.0 REMOTE I/O + PID, RS485 running. test with a short 4 wire telephon cable here the SLAVE with shield ( and FTDI for development und diagnostic ) but that was just a first test, next need one more slave on the link and i want modify the DIY DUINO to a LINK SLAVE CONTROLLER, so RS485 should be on main board. DIY LINK SLAVE layout and DIY LINK SLAVE circuit and more info partslist so, thats the new SLAVE CONTROLLER for 284Baht / 7 €.