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ASI (AS-Interface) Network Fundamentals and Configuration

By
Marek Halaczek
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Table of Contents

Introduction

Profinet, Profibus, and Actuator Sensor Interface (AS-Interface or ASI) are just a few of the networking options available for automation systems. In this tutorial, we will concentrate on the ASI. It uses a flat wire with a unique shape to connect various devices like actuators, sensors, push buttons, etc. It is widely used in material handling systems such as warehouses and airports. The price and convenience of installation and commissioning are its primary benefits.

In this article, we will look at how this network works, and what are ASI addresses. We will start by discussing general concepts, talk about common mistakes during commissioning, and finally, we will configure the ASI gateway in Siemens TIA Portal V17.

Understanding AS-Interface (ASI)

The ASI is a single-master system, which means that a single master device (ASI Gateway) exchanges data with all specified devices. The transmission medium is a two-wire yellow flat cable that is unshielded. The cable is utilized for signal transmission and power delivery at the same time. Direct powering of communication electronics and participants with low power requirements is possible. A separate, black flat wire can be used to give power to devices that require additional energy like motor starters.

The sensors or actuators are frequently connected using modules with a technology known as piercing. During installation, two penetrating mandrels pierce the insulation of the flat wire, allowing for a quick and easy connection with minimal assembly effort. Modules can be used to connect devices that do not have an ASI connection to the system.

Configuring an AS-Interface (ASI) gateway

After the ASI network has been powered up, the gateway must be configured to scan the network and discover all of the devices connected by their addresses. Although there are various types of ASI network divisions, the fundamentals stay the same, therefore we will focus on the most basic configuration. The network is divided into two ASI 1 and ASI 2 networks, each with its own set of cables, but addresses from the two networks may overlap. It is not permitted to have the same address of the device in one network.

The first step is to select:

1) Quick Setup, navigation is done using arrow buttons.

2) Store + Run

 

3) We will be presented with a warning, that it is important not to do this type of setup when the system is running.

4) If everything is right, we will be informed with a smiling face.

The instructions here are based on Pepperl and Fuchs ASI gateway, but they should be similar for other brands.

When it comes to exchanging some ASI devices on the network in an already commissioned system, the same actions must be followed. The device should be assigned an ASI number in the first step, and the gateway may require a similar configuration in the second phase.

AS-Interface (ASI) sensor module

We will look at how the connection appears in detail using the ASI sensor module Pepperl and Fuchs as an example.

  1. Yellow cable - carries power and data to the sensors.
  2. Black cable (AUX) - additional voltage supply to actuators.
  3. Special piercing technology, it easy to connect new devices.
  4. Cable connected to the ASI node.

It is critical to correctly install the wires in the housing, otherwise, the piercing technology may fail to connect. ASI flat cables have a unique design that forces them to be placed in only one correct position, and there is a notch on the cable that should also be positioned appropriately. Even if it is intended as follows, it is very simple to make a mistake when there are hundreds of those modules in one system, so this is the first place to look if something is wrong with the associated device.

AS-Interface (ASI) addressing

The ASI Gateway or an ASI address programming device is used to perform ASI addressing on the devices. This address is used to distinguish nodes in the ASI network. ASI Gateway with an address range that is defined in the TIA Portal hardware configuration will redistribute the IO addresses range to the relevant ASI nodes based on the ASI addresses in the devices. That is why ASI addressing is so critical because if the addresses of two ASI nodes are swapped, the IO will not be assigned appropriately.

AS-Interface (ASI) programmer

The principle of the ASI programmer is to assign an ASI address to the corresponding ASI nodes. The ASI node itself does not need to be powered, which is particularly useful during commissioning because this process can be completed even if the power is still unavailable.

We must first connect by cable to our ASI node, then push the ADR button to read the actual address and verify the connection, then use the arrows to select the address that we want to configure, then press the PRG button to assign the selected address to the device. The recommended practice is to press the read button (ADR) again to see if it was assigned.

AS-Interface (ASI) troubleshooting 

There are a few frequent problems that might arise during the initial setup of the ASI network, as well as while modifying or adding a new device to the network. I will go over each one and offer a solution.

  • The device appears to be connected to power (LEDs are on), but it is impossible to connect to it. The black and yellow cables at the connection point have likely been swapped. Another possibility is that adjustment at the connection point to the ASI network is required because the piercing might not function properly.
  • When the yellow ASI cable is correctly connected but the device requires AUX, it is often possible to establish communication between the master and node but not to actuate or read anything from it. In many circumstances, the AUX cable is not correctly fitted and the external power is missing. There is usually an LED indicator on the ASI node that may be checked.
  • Due to double addressing, the ASI gateway will prompt that a specific address has occurred twice in the network. Once established which device has an invalid address, it must be reassigned and the ASI gateway configuration must be executed.
  • There is an unknown node, and a new device has been connected. To resolve the issue, execute the ASI network configuration.

Adding ASI Gateway to the TIA Portal hardware configuration

We must first launch the TIA project that will be used to configure the ASI Gateway. The needed GSD/GSDML file must first be downloaded from the manufacturer's website. Then, from the drop-down menu, choose Options -> Manage general description files (GSD).

Select the folder in which the file is stored. Do not worry if it is not visible, all you have to do is select a folder and click Select Folder.

The next step is to select the file that we want to install, if there are more than one of such files in the folder, they will all be listed.

Installation is ongoing.

Complete prompt.

Go to Devices & Networks and select Hardware Catalog from the right-hand menu. To accelerate our search, copy the name of the file we just imported, paste it into the search area, and push enter, we will be directed to the requested location immediately.

The final step is to select the appropriate version and drag & drop it into our project.

The initial configuration has been completed. As with every device in the hardware configuration, the ASI gateway will require additional settings to be configured like IP address, subnet mask, and device number.

Conclusion

For many applications, the ASI network is sufficient. It is widely used in material handling systems due to its advantages.

In this tutorial, we explored some of the fundamentals of the ASI network. We configured an ASI gateway, discussed common ASI network issues, configured an ASI node, and finally integrated an ASI Gateway into our hardware configuration in TIA Portal.

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