diff --git a/devlib/bin/arm64/readenergy b/devlib/bin/arm64/readenergy
index c26991c..2918038 100755
Binary files a/devlib/bin/arm64/readenergy and b/devlib/bin/arm64/readenergy differ
diff --git a/devlib/platform/arm.py b/devlib/platform/arm.py
index e305dd1..cee399d 100644
--- a/devlib/platform/arm.py
+++ b/devlib/platform/arm.py
@@ -20,7 +20,7 @@ import time
 import pexpect
 
 from devlib.platform import Platform
-from devlib.instrument import Instrument, InstrumentChannel, MeasurementsCsv, CONTINUOUS
+from devlib.instrument import Instrument, InstrumentChannel, MeasurementsCsv, Measurement,  CONTINUOUS,  INSTANTANEOUS
 from devlib.exception import TargetError, HostError
 from devlib.host import PACKAGE_BIN_DIRECTORY
 from devlib.utils.serial_port import open_serial_connection
@@ -208,7 +208,7 @@ class TC2(VersatileExpressPlatform):
 class JunoEnergyInstrument(Instrument):
 
     binname = 'readenergy'
-    mode = CONTINUOUS
+    mode = CONTINUOUS | INSTANTANEOUS
 
     _channels = [
         InstrumentChannel('sys_curr', 'sys', 'current'),
@@ -238,6 +238,7 @@ class JunoEnergyInstrument(Instrument):
             self.channels[chan.name] = chan
         self.on_target_file = self.target.tempfile('energy', '.csv')
         self.command = '{} -o {}'.format(self.binary, self.on_target_file)
+        self.command2 = '{}'.format(self.binary)
 
     def setup(self):
         self.binary = self.target.install(os.path.join(PACKAGE_BIN_DIRECTORY,
@@ -281,4 +282,16 @@ class JunoEnergyInstrument(Instrument):
 
         return MeasurementsCsv(output_file, self.active_channels)
 
+    def take_measurement(self):
+        result = []
+        output = self.target.execute(self.command2).split()
+        reader=csv.reader(output)
+        headings=reader.next()
+        values = reader.next()
+        for chan in self.active_channels:
+            value = values[headings.index(chan.name)]
+            result.append(Measurement(value, chan))
+        print result
+        return result
+
 
diff --git a/src/readenergy/readenergy.c b/src/readenergy/readenergy.c
index cc945f7..1f33ab9 100644
--- a/src/readenergy/readenergy.c
+++ b/src/readenergy/readenergy.c
@@ -141,9 +141,10 @@ int nsleep(const struct timespec *req, struct timespec *rem)
  
 void print_help()
 {
-	fprintf(stderr, "Usage: readenergy [-t PERIOD] -o OUTFILE\n\n"
+	fprintf(stderr, "Usage: readenergy [-t PERIOD] [-o OUTFILE]\n\n"
 			"Read Juno energy counters every PERIOD milliseconds, writing them\n"
-			"to OUTFILE in CSV format until SIGTERM is received.\n\n"
+			"to OUTFILE in CSV format until SIGTERM is received.\n"
+			"If OUTFILE is not specified, stdout will be used.\n\n"
 			"Parameters:\n"
 			"	PERIOD is the counter poll period in milliseconds.\n"
 			"	       (Defaults to 100 milliseconds.)\n"
@@ -197,13 +198,6 @@ void config_init(struct config *this, int argc, char *argv[])
 				exit(EXIT_FAILURE);
 		}
 	}
-
-	if (this->output_file == NULL)
-	{
-		fprintf(stderr, "ERROR: Mandatory -o option not specified.\n\n");
-		print_help();
-		exit(EXIT_FAILURE);
-	}
 }
 
 // -------------------------------------- /config ---------------------------------------------------
@@ -219,13 +213,17 @@ struct emeter
 
 void emeter_init(struct emeter *this, char *outfile)
 {
-	this->out = fopen(outfile, "w");
-	if (this->out == NULL)
+	if(outfile)
 	{
-		fprintf(stderr, "ERROR: Could not open output file %s; got %s\n", outfile, strerror(errno));
-		exit(EXIT_FAILURE);
+		this->out = fopen(outfile, "w");
+		if (this->out == NULL)
+		{
+			fprintf(stderr, "ERROR: Could not open output file %s; got %s\n", outfile, strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+	} else {
+		this->out = stdout;
 	}
-
         this->fd = open("/dev/mem", O_RDONLY);
         if(this->fd < 0)
         {
@@ -243,10 +241,12 @@ void emeter_init(struct emeter *this, char *outfile)
 		exit(EXIT_FAILURE);
 	}
 
-	fprintf(this->out, "sys_curr,a57_curr,a53_curr,gpu_curr,"
- 			   "sys_volt,a57_volt,a53_volt,gpu_volt,"
-			   "sys_pow,a57_pow,a53_pow,gpu_pow,"
-			   "sys_cenr,a57_cenr,a53_cenr,gpu_cenr\n");
+	if(this->out) {
+		fprintf(this->out, "sys_curr,a57_curr,a53_curr,gpu_curr,"
+				   "sys_volt,a57_volt,a53_volt,gpu_volt,"
+				   "sys_pow,a57_pow,a53_pow,gpu_pow,"
+				   "sys_cenr,a57_cenr,a53_cenr,gpu_cenr\n");
+	}
 }
 
 void emeter_read_measurements(struct emeter *this, struct reading *reading)
@@ -333,11 +333,16 @@ int main(int argc, char *argv[])
 	config_init(&config, argc, argv);
 	emeter_init(&emeter, config.output_file);
 
-	struct timespec remaining;
-	while (!done) 
+	if(config.output_file)
 	{
+		struct timespec remaining;
+		while (!done)
+		{
+			emeter_take_reading(&emeter);
+			nsleep(&config.period, &remaining);
+		}
+	} else 	{
 		emeter_take_reading(&emeter);
-		nsleep(&config.period, &remaining);
 	}
 
 	emeter_finalize(&emeter);