diff --git a/src/logger.c b/src/logger.c
index 1c607da..9be93cd 100644
--- a/src/logger.c
+++ b/src/logger.c
@@ -43,9 +43,13 @@ int main (int argc, char *argv [])
 
   //----- Sanity checks
   mkdirp(__logdir);
+  if(__loginterval<MIN_INTERVAL){
+    printf("Log interval is too small (min=%ds)\n",MIN_INTERVAL);
+    exit(2);
+  }
   if(!FILE_EXISTS(__regpower)){
     printf("Logger cannot access to %s\n",__regpower);
-    exit(2);
+    exit(3);
   }
 
   //----- Start logging
diff --git a/src/utils.h b/src/utils.h
index 2b523cb..5acdedc 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -5,12 +5,14 @@
 #include <stdlib.h>
 #include <string.h>
 
-#define STR(symbol) #symbol
-#define STRINGIFY(symbol) STR(symbol)
+#define MIN_INTERVAL 30
 
 #define INA260_SYSFS "/sys/kernel/ina260"
 #define INA260_POWER_REGISTER "registers/power"
 
+#define STR(symbol) #symbol
+#define STRINGIFY(symbol) STR(symbol)
+
 #define INTERVAL(timestamp,duration)\
     ((timestamp) - ((timestamp)%(duration)))