diff --git a/fan-controller/src/fan/mod.rs b/fan-controller/src/fan/mod.rs
index 2fe4087..8bf7887 100644
--- a/fan-controller/src/fan/mod.rs
+++ b/fan-controller/src/fan/mod.rs
@@ -5,7 +5,6 @@ pub(crate) mod set_point;
 
 use core::str::FromStr;
 
-use crate::modbus::ReadInputRegister;
 use crate::{configuration, modbus};
 use defmt::{error, info, Format};
 use embassy_rp::dma::Channel;
diff --git a/fan-controller/src/modbus/client.rs b/fan-controller/src/modbus/client.rs
index 0c5951f..ad6ecf5 100644
--- a/fan-controller/src/modbus/client.rs
+++ b/fan-controller/src/modbus/client.rs
@@ -12,7 +12,7 @@ use embedded_io_async::{Read, Write};
 use crate::{
     configuration,
     fan::{self, address, holding_registers, set_point::SetPoint, Fan, FanResponse, BAUD_RATE},
-    modbus::{self, ReadInputRegister},
+    modbus::{self, function::read_input_register::ReadInputRegister},
 };
 
 pub(crate) enum Error {
@@ -189,7 +189,7 @@ impl<'a, UART: uart::Instance, PIN: Pin> Client<'a, UART, PIN> {
             // Device address fan 1
             address::FAN_1,
             // Modbus function code
-            modbus::function_code::WRITE_SINGLE_REGISTER,
+            modbus::function::code::WRITE_SINGLE_REGISTER,
             // Holding register address
             holding_registers::REFERENCE_SET_POINT[0],
             holding_registers::REFERENCE_SET_POINT[1],
@@ -249,7 +249,7 @@ impl<'a, UART: uart::Instance, PIN: Pin> Client<'a, UART, PIN> {
                 Fan::Two => address::FAN_2,
             },
             // Modbus function code
-            modbus::function_code::READ_INPUT_REGISTER,
+            modbus::function::code::READ_INPUT_REGISTER,
             // Input register address
             fan::input_registers::TEMPERATURE_SENSOR_1[0],
             fan::input_registers::TEMPERATURE_SENSOR_1[1],
diff --git a/fan-controller/src/modbus/function/code.rs b/fan-controller/src/modbus/function/code.rs
new file mode 100644
index 0000000..5fa6527
--- /dev/null
+++ b/fan-controller/src/modbus/function/code.rs
@@ -0,0 +1,3 @@
+pub const READ_HOLDING_REGISTER: u8 = 0x03;
+pub const READ_INPUT_REGISTER: u8 = 0x04;
+pub const WRITE_SINGLE_REGISTER: u8 = 0x06;
diff --git a/fan-controller/src/modbus/function/mod.rs b/fan-controller/src/modbus/function/mod.rs
new file mode 100644
index 0000000..1edfdce
--- /dev/null
+++ b/fan-controller/src/modbus/function/mod.rs
@@ -0,0 +1,6 @@
+pub(super) mod code;
+pub(crate) mod read_input_register;
+
+pub(crate) trait Function {
+    const CODE: u8;
+}
diff --git a/fan-controller/src/modbus/function/read_input_register.rs b/fan-controller/src/modbus/function/read_input_register.rs
new file mode 100644
index 0000000..3d50ef5
--- /dev/null
+++ b/fan-controller/src/modbus/function/read_input_register.rs
@@ -0,0 +1,19 @@
+use crate::modbus::function::{self, Function};
+
+pub(crate) struct ReadInputRegister {
+    pub(crate) address: u16,
+    pub(crate) number_of_registers: u16,
+}
+
+impl ReadInputRegister {
+    pub(crate) fn new(address: u16, number_of_registers: u16) -> Self {
+        Self {
+            address,
+            number_of_registers,
+        }
+    }
+}
+
+impl Function for ReadInputRegister {
+    const CODE: u8 = function::code::READ_INPUT_REGISTER;
+}
diff --git a/fan-controller/src/modbus/mod.rs b/fan-controller/src/modbus/mod.rs
index cd5cf4b..7e7c898 100644
--- a/fan-controller/src/modbus/mod.rs
+++ b/fan-controller/src/modbus/mod.rs
@@ -1,11 +1,9 @@
 pub(crate) mod client;
+mod function;
 
 use crc::{Crc, CRC_16_MODBUS};
-pub(super) mod function_code {
-    pub const READ_HOLDING_REGISTER: u8 = 0x03;
-    pub const READ_INPUT_REGISTER: u8 = 0x04;
-    pub const WRITE_SINGLE_REGISTER: u8 = 0x06;
-}
+
+use crate::modbus::function::{read_input_register::ReadInputRegister, Function};
 
 /// Used to create CRC checksums when forming modbus messages
 pub(super) const CRC: Crc<u16> = Crc::<u16>::new(&CRC_16_MODBUS);
@@ -32,31 +30,9 @@ pub(super) const fn get_message_delay(baud_rate: u32) -> u64 {
     MICROSECONDS_FOR_BITS.div_ceil(baud_rate as u64)
 }
 
-pub(crate) trait Function {
-    const CODE: u8;
-}
-
-pub(crate) struct ReadInputRegister {
-    address: u16,
-    number_of_registers: u16,
-}
-
-impl ReadInputRegister {
-    pub(crate) fn new(address: u16, number_of_registers: u16) -> Self {
-        Self {
-            address,
-            number_of_registers,
-        }
-    }
-}
-
-impl Function for ReadInputRegister {
-    const CODE: u8 = function_code::READ_INPUT_REGISTER;
-}
-
 pub(crate) struct Message<F> {
-    address: u8,
-    function: F,
+    device_address: u8,
+    pub(crate) function: F,
 }
 
 pub(crate) trait ToBytes<const LENGTH: usize> {
@@ -69,7 +45,7 @@ impl ToBytes<8> for Message<ReadInputRegister> {
         let length_bytes = self.function.number_of_registers.to_be_bytes();
         let mut buffer = [
             // Device address
-            self.address,
+            self.device_address,
             // Modbus function code
             self.code(),
             // Starting address
@@ -93,7 +69,10 @@ impl ToBytes<8> for Message<ReadInputRegister> {
 
 impl<F: Function> Message<F> {
     pub(crate) fn new(address: u8, function: F) -> Self {
-        Self { address, function }
+        Self {
+            device_address: address,
+            function,
+        }
     }
 
     const fn code(&self) -> u8 {