Most major lift suppliers now offer remote monitoring systems, which are ideal if you have lifts and servicing from one company. However, data available is of minimal value to researchers who need a log of every event, such as lift movement and door operation. They are even less ideal when lift maintenance companies are not performing, as they are effectively writing their own reports. And finally, where companies manage lifts in different buildings with a range of equipment from multiple suppliers, they need a lift and escalator monitoring (LEM) system that can monitor their whole estate.
This is the context in which the authors began to develop a LEM solution, with a focus on building owners and property management companies that operate multiple sites with lift and escalator equipment from multiple vendors. A manufacturer’s monitoring system could potentially report the part number of a failed component, for example, but those who are managing an estate have different requirements, including: being messaged if a lift goes out of service or goes into a special mode, such as car top control; being able to see if lifts are in use; being able to respond to a report that a lift is out of service remotely; and having access to historical data.
To address the range of interface possibilities, a custom LEM interface board (pictured, p17) was developed that would accept all the widely used communication formats – Ethernet, USB, two CAN channels, five RS 485, and one RS 232 or RS 485 channel. An SD card is used to store information.
PROTOCOLS & DISCRETE INTERFACES
With the hardware in place, the biggest challenge is protocols. Lift companies prefer to sell their own monitoring solutions, so are reluctant to share their protocols unless agreed as part of the contract specification and protected by non-disclosure agreements. Confidentiality agreements have been signed in order to gain access to proprietary protocols. These have generally been obtained when specific clauses for the monitoring system have been included in a new specification. With the right interface, all the lifts and escalators in a major development can be connected with a single interface board.
Adoption of standard or open communications protocols is not a popular cause within the lift and escalator industry. But it does seem an awful waste of the industry’s time and clients’ money to have so many different communication methods and proprietary protocols. The authors have invested heavily in Transmission Control Protocol/Internet Protocol (TCP/IP) communication in the vertical transportation domain and are open to cooperation with others who share the goal of open communications protocols.
Upgrading an existing lift controller to add a LEM interface is possible, but typically more expensive to achieve. This assumes discrete (volt-free) inputs, which must be converted into a digital format before being received by the LEM interface board. Although discrete (volt-free relay) interfaces are ubiquitous and relatively simple to implement, they rely on moving parts and connections that can come loose. With a large building, there could be 1,000s of relays that could be replaced by a single digital connection linked to a single LEM board.
INDICATOR NETWORK
A more cost-effective approach for existing (and sometimes new) installations is to interface with an existing indicator network already connected to the controller. To this end, LEM interfaces with two populator indicator suppliers, CE Electronics and Drucegrove, have been developed. This opens the possibility of a low-cost interface to a vast array of lift controllers where non-proprietary indicators have already been installed. The LEM board communicates directly with the indicator network board using RS485.
The indicator interface route does provide a low-cost route to implementation. However, not all the inputs/outputs required by those managing an estate are available, but with some basic artificial intelligence, some issues can be inferred, such as breakdown or a maintenance mode when a lift is not moving regularly at times when it is normally, even though the rest of the lift group is.
It is also practical to implement connection-free interfaces using an accelerometer to determine floor position. Accelerometers have been demonstrated to be an effective connection diagnostic tool and can be installed without direct connection to the controller. Again, not all the inputs/outputs required are available, but the cost benefit is such that it is a solution worth considering. Connecting the accelerometer to the internet is possible, but a retrofit is likely to require use of a wireless connection.
LOCAL & CLOUD
Historically, lift and escalator monitoring systems provided by manufacturers have had dedicated local networks. Some systems have provided remote access. The trend from local monitoring servers to cloud-based services in building automation systems is also reflected in lift and escalator monitoring systems. With a cloud-based system, no equipment other than the interface board is needed on site.
In the system discussed in this paper, the LEM board communicates directly to the server which reports via web pages. The LEM board talks to a server only using https (hypertext transfer protocol secure), which is the protocol used by a web browser. This avoids the need to configure firewalls and open specific ports; if the internet connection provided can view a web page, it can talk to the LEM board.
When connected via Ethernet locally, the LEM board displays an internal web page for an engineer who can make changes in configuration and review current status. The board software may be updated from a local PC via Ethernet or from a web server via remote control, allowing for offsite software development and debugging. Remote download of software updates has been a major benefit.
In all cases, to fit and forget, a wire is always more reliable than wireless.Although mobile broadband and wireless connections are available, it is wise to extend the building Ethernet network to every lift motor room, escalator pit and lift cab when specifying a new job or refurbishment.
Multiple groups of lifts and escalators are brought together on a static display with colour changes to indicate if a lift or escalator is not in normal service. The green N indicates normal operation, and the lift position and door states are shown with the current floor mnemonic overwritten on the lift graphic. Alerts are programmable so that any change of state, such as normal to out of service or inspection service, can trigger an alert email. The main value to those managing an estate is knowing immediately that a lift or escalator has broken down.
Lift maintenance companies and personnel are understandably wary of third-party cloud-based monitoring systems, but in a world where devices from different vendors are increasing being connected to the internet and each other, the application of this technology is inevitable for the lift and escalator industry. LEM will highlight companies and personnel that deliver a good service. Recognising this can only help support a rise in standards.
BOX OUT: Additional information
Richard Peters is a director of Peters Research and a Visiting Professor at the University of Northampton. Jim Nickerson has been working with Peters Research as a Software Engineer Consultant since 2009. Their paper, Lift and Escalator Management Systems: Requirements and Implementation, was presented at the 10th Symposium on Lift & Escalator Technology (CIBSE Lifts Group, The University of Northampton and LEIA) in September 2019. The full research paper can be found at: www.is.gd/afiziq.