4081 User Manual

Issue 2

(these subsequent units should have the blue USB/RS485 button on the rear pushed out to select RS485 control).

The RS 485 communication protocol uses standard RJ9 connectors for connecting cables where multiple units can be chained together (cabling not supplied).

Please note that when connecting multiple units, each 4081 should have a unique ID as described below.

Cable Specification

The RS-422 specification recommends 24AWG twisted pair cable with a shunt capacitance of 16 pF per foot and 100 ohm characteristic impedance.

These recommendations should be used for RS-485 systems as well.

We also recommend using shielded cable.

There are many cables available meeting the recommendations of RS-485 made specifically for this application. Another choice is the same cable commonly used in the twisted pair Ethernet cabling. This cable, commonly referred to as Category 5 cable, is defined by the EIA/TIA/ANSI 568 specification.

This cable has a maximum capacitance of 17 pF/ft (14.5 pF typical) and characteristic impedance of 100 ohms.

Category 5 cable is available as shielded twisted pair (STP) as well as unshielded twisted pair (UTP) and generally exceeds the recommendations for RS-422 making it an excellent choice for RS-422 and RS-485 systems.

4081 unit ID dip switches

When remotely controlling more than one unit, the ID dip-switches on the rear of the unit need to be set so that each sequentially numbered unit on the chain responds to the correct commands.

The first 3 switches from left to right are used to set the machine IDs from 1-8. These switches are On when in the down position (the right-most switch on this block – Switch 4 - puts the unit into 'Bootloader Mode' where the unit software can be updated via USB, so is therefore not used to set the unit ID).

Unit ID

Switch 1

Switch 2

Switch 3

1

Off

Off

Off

 

 

 

 

2

On

Off

Off

3

Off

On

Off

4

On

On

Off

5

Off

Off

On

6

On

Off

On

7

Off

On

On

8

On

On

On

 

 

 

 

Where there are more than 8 units on an RS 485 chain, the IDs for units greater than 8 are set using a dip-switch on the switch-block labelled SW2 inside the unit (just next to a programming connector labelled J14 on the middle left of the board).

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AMS 4081 user manual Unit ID dip switches

4081 specifications

AMS 4081 is a high-performance material specification for aluminum alloy products, primarily aimed at aerospace applications. This specification outlines the requirements for aluminum alloy 7075, which is known for its exceptional mechanical properties and high strength-to-weight ratio. Engineers and manufacturers in the aerospace sector often select AMS 4081 due to its superior fatigue resistance and excellent stress corrosion cracking resistance, making it ideal for critical components subjected to extreme operational conditions.

One of the key features of AMS 4081 is its impressive strength, which stems from the alloying elements of zinc, magnesium, and copper. These elements work synergistically to enhance the material's tensile strength while maintaining ductility. The yield strength of 7075 aluminum can reach up to 570 MPa (depending on the temper), resulting in components that can withstand substantial loads without deforming. This strength is especially crucial for aerospace applications where safety and reliability are paramount.

Another notable characteristic of AMS 4081 is its heat treatability. The alloy can be heat-treated to achieve a range of mechanical properties tailored to specific applications. The solution heat treatment followed by aging allows for the formation of precipitates that enhance strength, making it suitable for demanding aircraft structures, including fuselage frames, wing ribs, and landing gear components.

In terms of technologies, AMS 4081 incorporates advanced production techniques such as controlled casting and rolling. These processes ensure uniformity in the microstructure, which directly influences mechanical properties. Furthermore, modern fabrication technologies, including CNC machining and additive manufacturing, are compatible with 7075 aluminum, allowing for the efficient production of complex geometries.

Corrosion resistance is another critical feature of AMS 4081. Although aluminum is naturally resistant to corrosion due to the formation of a protective oxide layer, the additional treatment processes specified in AMS 4081 further enhance this property. The material can undergo surface treatments such as anodizing, which provides an additional barrier against corrosion, extending the lifespan of components exposed to harsh environments.

In conclusion, AMS 4081 stands out in the aerospace industry due to its high strength, heat treatability, and enhanced corrosion resistance. Its advanced manufacturing capabilities make it a preferred choice for engineers looking to design lightweight yet robust components in the pursuit of improved performance and safety in aerospace applications.