Adjusted mutex lock and delay for modbus

src/digitalIO.h

@@ -28,7 +28,7 @@ private:
         DI_MAX
     };
 
-    const uint8_t maxRetries = 5;
+    const uint8_t c_maxRetries = 5;
 
 public:
     digitalIO(drivers::I2C &i2c, drivers::MODBUS &bus, std::vector<uint8_t> remotes);