Add temperature conversion. Example usage: ethstream -vvv -c -L -C 141 -r 10

git-svn-id: https://bucket.mit.edu/svn/nilm/acquisition/ethstream@9728 ddd99763-3ecb-0310-9145-efcb8ce7c51f

ethstream.c

@@ -57,7 +57,7 @@ struct options opt[] = {
 	{'g', "gain", "a,b,c", "Set Labjack AIN channel gains: 0,1,2,4,8 in -C channel order"},
 	{'o', "oneshot", NULL, "don't retry in case of errors"},
 	{'f', "forceretry", NULL, "retry no matter what happens"},
-	{'c', "convert", NULL, "convert output to volts"},
+	{'c', "convert", NULL, "convert output to volts/temperature"},
 	{'H', "converthex", NULL, "convert output to hex"},
 	{'m', "showmem", NULL, "output memory stats with data (NJ only)"},
 	{'l', "lines", "num", "if set, output this many lines and quit"},
@@ -775,6 +775,12 @@ int data_callback(int channels, int *channel_list, int gain_count, int *gain_lis
 						   12, data[i])) < 0)
 					goto bad;
 			}
+		} else if (ci->convert == CONVERT_VOLTS &&
+			   (channel_list[i] == 141 || channel_list[i] == 133)) {
+			/* CONVERT_VOLTS but output temperature */
+			if (printf("%lf", ue9_binary_to_temperature(
+					   &ci->calib, data[i])) < 0)
+				goto bad;
 		} else if (ci->convert == CONVERT_HEX) {
 			/* CONVERT_HEX */
 			if (printf("%04X", data[i]) < 0)

ue9.c

@@ -116,6 +116,20 @@ int ue9_verify_extended(uint8_t * buffer, size_t len)
 	return 1;
 }
 
+/* Temperature conversion.  If calib is NULL, use uncalibrated conversions. */
+double ue9_binary_to_temperature(struct ue9Calibration *calib, uint16_t data)
+{
+	double slope;
+
+	if (calib == NULL) {
+		slope = 0.012683;
+	} else {
+		slope = calib->tempSlope;
+	}
+
+	return data * slope; /* output is in Kelvin */
+}
+
 /* Data conversion.  If calib is NULL, use uncalibrated conversions. */
 double
 ue9_binary_to_analog(struct ue9Calibration *calib,
@@ -804,6 +818,6 @@ ue9_stream_data(int fd, int channels, int *channel_list, int gain_count, int *ga
 
 /*
 Local variables:
-c-basic-offset: 2
+c-basic-offset: 8
 End:
 */

ue9.h

@@ -106,6 +106,9 @@ int ue9_get_control_config(int fd, struct ue9ControlConfig *config);
 double ue9_binary_to_analog(struct ue9Calibration *calib,
 			    int gain, uint8_t resolution, uint16_t data);
 
+/* Temperature conversion.  If calib is NULL, use uncalibrated conversions. */
+double ue9_binary_to_temperature(struct ue9Calibration *calib, uint16_t data);
+
 /* Compute scanrate based on the provided values. */
 double ue9_compute_rate(uint8_t scanconfig, uint16_t scaninterval);