For the machine manufacturer, remote maintenance means the ability to offer faster response and lower costs to their customers. Remote maintenance not only helps with breakdowns, identifying the fault and reducing the downtime, but can also speed commissioning, allow software updates, data acquisition and predict servicing needs.
Imagine the scenario where a commissioning engineer is at site a long way from his or her company, and requires support from experts at head office. It is difficult to describe the exact problem over the telephone. Previously such cases required a colleague to travel to the site in order to solve the problem as quickly as possible. The journey time is usually significantly longer than the time spent working on site. Here remote maintenance allows great savings to be made, as the time of the expert can be used much more efficiently, saving cost-intensive resources.
If a machine breaks down, help is needed quickly. If the error cannot be located immediately due to lack of skilled personnel locally, then service engineers with the requisite skills have to make the journey to site, thus extending down times still further.
However, problems can sometimes be remedied relatively easily using software. It might simply be a case of acknowledging a message or modifying a parameter. Even if the error cannot be corrected using software, service engineers can still pinpoint the nature of the fault, agree remedial strategies with colleagues and obtain any necessary spare parts remotely. Although service resources still need to be deployed, the process can be carried out much more efficiently, thus reducing costs.
A classic remote maintenance solution is a dial-up connection. Such direct switched connections are the simplest form of remote maintenance. In such cases it is sufficient to make an analogue telephone line available at the plant. The technical installation is clear and simple. It is also relatively easy to protect access by using password mechanisms or call back. Such designs are simply individual solutions which can only be used in conjunction with specific components. This can lead to the use of different modems, each with a separate telephone line, being required for the remote maintenance of devices supplied by different manufacturers.
To some extent these disadvantages can be balanced out by connecting the individual components that are to be maintained remotely to a higher level system, for example, via Ethernet. However, this necessarily raises questions concerning integration into IT systems and such solutions have to be agreed with IT departments, not set up by an engineer working in isolation. For this reason simple dial-up connections are still a very common and popular solution.
Lenze offers the ModemCAN communication module for classic switched connections. This is a CANopen device for DIN rail mounting with an integrated analogue modem configurable for all relevant countries worldwide. For “exotic” telephone standards or others such as ISDN or GSM, modems can be connected to the Lenze ModemCAN via RS232. Password protection and call-back ensures that access is secure. Buffering large data packages brings in the risk that data transfer may be incomplete if a connection is interrupted, thus leaving the device in an undefined state. The ModemCAN is designed to only forward the data via the CANbus once it has all been received.
The simple, clear solution described above is beneficial for applications with a small number of nodes. The limits of the architecture become apparent when it is used to maintain larger plant remotely, because the expenditure involved in providing individual machine components, or even individual machines with a separate telephone line, cannot be justified. A comprehensive solution which allows as many components as possible to be maintained remotely via uniform access path must be found for such applications. This can be achieved by initially implementing access via Ethernet for all devices to be remotely maintained. Various standard solutions exist for remote access to Ethernet networks. The appropriate solution can be selected in accordance with requirements in respect of security, availability and various transmission media. Standard Ethernet also provides the basis for the use of low cost standard components for remote maintenance.
Many modern devices, including the new Lenze L-force servo drives from the 9400 range, already feature onboard Ethernet interfaces. If these do not exist, fieldbus converters can be used to establish the connection to Ethernet. Lenze offers the EthernetCAN communication model for this purpose. This is a CANopen device which facilitates access to other such CANopen devices via Ethernet. These varied applications including networking in large plants. It allows CANbus line to be short and confined within the control cabinet. Ethernet, for which line length is not critical, is then used to make the connection to higher level systems. This also provides a means of physically isolating a number of CAN lines, yet still enables all devices to be accessed simultaneously from a single connected PC.
Increasingly machine manufacturers are seeing the advantages or remote maintenance in terms of improved service to their customers. Lenze offer secure solutions for simple and complex cases. Today it is possible to remotely monitor all aspects of machine performance with immediate response to problems, even predicting problems before they happen.