Hi thanks Digger some progress this
byte relay_address1;
void setup(){
Serial.begin(9600);
}
void loop(){
Serial.print(relay_address1, BYTE); // send relay module address
Serial.print(100, BYTE); // All relays on
Serial.print(relay_address1, BYTE); // send relay module address
Serial.print(101, BYTE); // Turn relay 1 off
delay(1000);
//etc
}
gets various letters sent over the serial and the delay helps but still no rela switching .I did get relay 5 to latch on but I think this is a fluke because I had to disconnect the board to get it off and could not repeat the situation .
Will cary on experimenting