uint8 campbell_cond_br_read(float* Rs){
uint8 i, chan = 0u;
AMux_1_Select(chan);
// if i == 5, Mux could not be reset to 0
ADC_DelSig_1_StartConvert();
CyDelay(1u);
for (i = 0u; i < 100; i++) {
if(ADC_DelSig_1_IsEndConversion(ADC_DelSig_1_RETURN_STATUS)){
if (chan == 0)
{
ADC_DelSig_1_StopConvert(); // Stop the conversion so signals don't
// get mixed when switching the mux
chan = 1u;
AMux_1_Select(chan);
res1 = ADC_DelSig_1_GetResult16();
dvpp = ADC_DelSig_1_CountsTo_Volts(res1) ;
CyDelay(1u);
ADC_DelSig_1_StartConvert();
CyDelay(49u);
}
else {
ADC_DelSig_1_StopConvert(); // Stop the conversion so signals don't
// get mixed when switching the mux
AMux_1_DisconnectAll();
res2 = ADC_DelSig_1_GetResult16();
vpp1 = (ADC_DelSig_1_CountsTo_Volts(res2)/2);
vpp2 = vpp1 - dvpp;
break;
}
}
CyDelay(1u);
}
//*Rs_half = 2*(vpp2-(vpp1)/2)/(vpp1); // BR_HALF: Voltage divider between Cond LO and GND
//*Rs_full = 2*(vpp2-(vpp1)/2)/(vpp1); // BR_FULL: Reversed Differential measurement bewteen Cond HI and cond LO
//*Rs_half = vpp2/vpp1; // BR_HALF: Voltage divider between Cond LO and GND
*Rs = vpp2/vpp1; // BR_FULL: Reversed Differential measurement bewteen Cond HI and cond LO
// ADC range is configured as min(v1) +/- 6.114
// Readings are expected to be between min(v1) to +6.114
// and misreading min(v1) as max(v1) results in overflow (eg values like 7.8 and 11)
if (vpp1 > 6.114 || vpp2 > 6.114) {
return 0u;
// Range of excitation signal is 2-2.5 VAC
} else if (vpp1 > 2.6) {
return 0u;
// vpp2 should always be less than vpp1
} else if (*Rs > 1) {
return 0u;
} else if (*Rs < 0) {
return 0u;
} else {
return 1u;
}
}
/*******************************************************************************
* Function Name: AMux_1_Select
********************************************************************************
* Summary:
* This functions first disconnects all channels then connects the given
* channel.
*
* Parameters:
* channel: The channel to connect to the common terminal.
*
* Return:
* void
*
*******************************************************************************/
void AMux_1_Select(uint8 channel)
{
AMux_1_DisconnectAll(); /* Disconnect all previous connections */
AMux_1_Connect(channel); /* Make the given selection */
AMux_1_lastChannel = channel; /* Update last channel */
}
uint8 campbell_temp_br_read(float* VsVx){
uint8 i, chan = 2u;
float mult = 1.0, ratio = 0.0, R = 0.0;
if (! campbell_temp_start()) {
return 0u;
}
AMux_1_Select(chan);
ADC_DelSig_1_StartConvert();
CyDelay(100u);
for (i = 0u; i < 100; i++) {
if(ADC_DelSig_1_IsEndConversion(ADC_DelSig_1_RETURN_STATUS)){
if (chan == 2)
{
ADC_DelSig_1_StopConvert(); // Stop the conversion so signals don't
// get mixed when switching the mux
res1 = ADC_DelSig_1_GetResult16();
Vx = ADC_DelSig_1_CountsTo_Volts(res1) ;
mult = 8/Vx; // See Sec 12 http://s.campbellsci.com/documents/au/manuals/cs547a.pdf
// Multiplier scales Vx to 8000 mV
chan = 3u;
AMux_1_Select(chan);
//ADC_DelSig_1_SelectConfiguration(2u, 1u);
CyDelay(1u);
ADC_DelSig_1_StartConvert();
CyDelay(99u);
}
else {
ADC_DelSig_1_StopConvert(); // Stop the conversion so signals don't
// get mixed when switching the mux
AMux_1_DisconnectAll();
res2 = ADC_DelSig_1_GetResult16();
Vs = ADC_DelSig_1_CountsTo_Volts(res2) ;
break;
}
}
CyDelay(1u);
}
if (! campbell_temp_stop()) {
return 0u;
}
//*VsVx = mult * VsVx * 8000;
ratio = Vs/Vx; // Added to adjust for using 100 kOhm instead of 1 kOhm
R = (100000 - (ratio*349000)) / ratio; // Added to adjust for using 100 kOhm instead of 1 kOhm
*VsVx = 1000 / (R + 250000) * 8000; // Now that Rs is known, use original equation
// note: Datasheet says 800, but 8000 yields correct results
// According to Therm107 Datasheet, http://s.campbellsci.com/documents/au/manuals/107.pdf
// VsVx*8000 should range between 0 and 30
if (*VsVx > 0 && *VsVx < 30) {
return 1u; // Result is valid
} else {
return 0u;
}
}
