diff --git a/examples/serial/mb_serial_master/main/serial_master.c b/examples/serial/mb_serial_master/main/serial_master.c
index b0e1098..df67a65 100644
--- a/examples/serial/mb_serial_master/main/serial_master.c
+++ b/examples/serial/mb_serial_master/main/serial_master.c
@@ -20,7 +20,7 @@
 #define MASTER_MAX_CIDS num_device_parameters
 
 // Number of reading of parameters from slave
-#define MASTER_MAX_RETRY                (10)
+#define MASTER_MAX_RETRY                (1000)
 
 // Timeout to update cid over Modbus
 #define UPDATE_CIDS_TIMEOUT_MS          (500)
@@ -149,10 +149,10 @@ const mb_parameter_descriptor_t device_parameters[] = {
             OPTS( 0xAA, 0x15, 0 ), PAR_PERMS_READ_WRITE_TRIGGER },
     { CID_RELAY_P2, STR("RelayP2"), STR("on/off"), MB_DEVICE_ADDR1, MB_PARAM_COIL, 10, 6,
             COIL_OFFSET(coils_port1), PARAM_TYPE_U8, 1, 
-            OPTS( 0x55, 0x2A, 0 ), PAR_PERMS_READ_WRITE_TRIGGER },
+            OPTS( 0x55, 0x2A, 0xAA ), PAR_PERMS_READ_WRITE_TRIGGER },
     { CID_DISCR_P1, STR("DiscreteInpP1"), STR("on/off"), MB_DEVICE_ADDR1, MB_PARAM_DISCRETE, 2, 7,
             DISCR_OFFSET(discrete_input_port1), PARAM_TYPE_U8, 1, 
-            OPTS( 0xAA, 0x15, 0 ), PAR_PERMS_READ_WRITE_TRIGGER },
+            OPTS( 0xAA, 0x15, 0x55 ), PAR_PERMS_READ_WRITE_TRIGGER },
 #if CONFIG_FMB_EXT_TYPE_SUPPORT
     { CID_HOLD_U8_A, STR("U8_A"), STR("__"), MB_DEVICE_ADDR1, MB_PARAM_HOLDING, 
             TEST_HOLD_REG_START(holding_u8_a), TEST_HOLD_REG_SIZE(holding_u8_a),
@@ -445,7 +445,7 @@ static void master_operation_func(void *arg)
                     float value = *(float *)temp_data_ptr;
                     if (((value > param_descriptor->param_opts.max) ||
                         (value < param_descriptor->param_opts.min))) {
-                            alarm_state = true;
+                            //alarm_state = true;
                             break;
                     }
                 } else if ((cid >= CID_RELAY_P1) && (cid <= CID_DISCR_P1)) {
@@ -466,11 +466,11 @@ static void master_operation_func(void *arg)
                                         (char *)param_descriptor->param_units,
                                         (const char *)rw_str,
                                         *(uint8_t *)temp_data_ptr);
-                            alarm_state = true;
+                            //alarm_state = true;
                             break;
                         }
                         if (state & param_descriptor->param_opts.opt1) {
-                            alarm_state = true;
+                            //alarm_state = true;
                             break;
                         }
                     }
@@ -567,11 +567,24 @@ static esp_err_t master_init(void)
     return err;
 }
 
+#include "esp_heap_trace.h"
+
+#define NUM_RECORDS 100
+static heap_trace_record_t trace_record[NUM_RECORDS]; 
+
 void app_main(void)
 {
     // Initialization of device peripheral and objects
     ESP_ERROR_CHECK(master_init());
     vTaskDelay(10);
 
+    ESP_ERROR_CHECK( heap_trace_init_standalone(trace_record, NUM_RECORDS) );
+
+    ESP_ERROR_CHECK( heap_trace_start(HEAP_TRACE_LEAKS) );
+
     master_operation_func(NULL);
+
+    ESP_ERROR_CHECK( heap_trace_stop() );
+    heap_trace_dump();
+
 }