diff --git a/src/mgos_si7021.c b/src/mgos_si7021.c
index 0e257bd..5117482 100644
--- a/src/mgos_si7021.c
+++ b/src/mgos_si7021.c
@@ -19,6 +19,19 @@
 #include "mgos_i2c.h"
 
 // Private functions follow
+static bool mgos_si7021_cmd(struct mgos_si7021 *sensor, uint8_t cmd) {
+
+  if (!sensor || !sensor->i2c)
+    return false;
+
+  if (!mgos_i2c_write(sensor->i2c, sensor->i2caddr, &cmd, 1, true)) {
+    LOG(LL_ERROR, ("I2C=0x%02x cmd=%u (0x%02x) write error", sensor->i2caddr, cmd, cmd));
+    return false;
+  }
+  LOG(LL_DEBUG, ("I2C=0x%02x cmd=%u (0x%02x) write success", sensor->i2caddr, cmd, cmd));
+  return true;
+}
+
 static uint8_t crc8(const uint8_t *data, int len)
 {
   const uint8_t POLYNOMIAL=0x31;
@@ -76,10 +89,9 @@ bool mgos_si7021_read(struct mgos_si7021 *sensor) {
   }
   // Read out sensor data here 
   //
-  uint8_t cmd = MGOS_SI7021_MEASRH_NOHOLD_CMD;
   uint8_t data[3];
 
-  if (!mgos_i2c_write(sensor->i2c, sensor->i2caddr, &cmd, 1, false)) {
+  if (!mgos_si7021_cmd(sensor, MGOS_SI7021_MEASRH_NOHOLD_CMD)) {
     LOG(LL_ERROR, ("Could not write command"));
     return false;
   }
@@ -99,8 +111,7 @@ bool mgos_si7021_read(struct mgos_si7021 *sensor) {
   humidity -= 6;
   sensor->humidity = humidity;
 
-  cmd=MGOS_SI7021_MEASTEMP_NOHOLD_CMD;
-  if (!mgos_i2c_write(sensor->i2c, sensor->i2caddr, &cmd, 1, false)) {
+  if (!mgos_si7021_cmd(sensor, MGOS_SI7021_MEASTEMP_NOHOLD_CMD)) {
     LOG(LL_ERROR, ("Could not write command"));
     return false;
   }