Rated capacity indicators ready to test

20 October 2011

This month, the equipment review section of Cranes Today focuses on operator assistance devices. More specifically we’ll be taking a look at some of the most recently released rated capacity indicators available for mobile hydraulic cranes. Kevin Walsh reports.

Since the company’s inception in 1990, Rezonans has become one of the leading providers of electronic systems for cranes in the Commonwealth of Independent States (CIS), and is currently integrating a quality management system into its processes that is compliant with the ISO 9001:2008 standard.

At present, Rezonans most newly-developed control product that also carries out the functions of a rated capacity indicator is the SBUC control system that is compatible with both hydraulic and electric drives.

Although Rezonans first released the SBUC in 2009, there have been several versions of the model released with modifications specific to each application. Back in 2009 the SBUC was first supplied to Ivanovo Autocrane Plant for use with 80t Ivanovets KS-7474 truck cranes, but more recently, at the start of this year, the company has been fitting its model 302 SBUCs to 50t Ivanovets KC-63731 cranes.

The modular design of SBUC control system consists of unified controllers, a digital sensor array, industrial joysticks with integrated 5-button direct digital controls and an IP 67 rated 800 x 480 TFT display screen.

Its primary functions include operating actuators, such as discrete hydrovalves and solenoids, monitoring productivity and fuel usage, along with monitoring and control of the safe working parameters of the crane.

Rezonans says that SBUC control unit’s casing has strong thermal properties that help with effective temperature control of the unit during operation. This allows the unit to operate effectively at temperatures between -40°C and 60°C, with a reduction in the number of heating and cooling elements that minimizes the 1kg unit’s size.

Along with Bluetooth and optional wireless connectivity, the SBUC features six inputs, up to four of which are analogue inputs, along with a maximum of 12 proportional outputs capable of handling currents of up to 3A. All input and output circuits in the system are protected, and are compatible with RBUS and CAN interfaces.

The firm also offers the OGM 240 series of rated capacity indicators for cranes with lifting capacities up to least 150t which are configurable using just one test load.

This series was originally commissioned in 2001, but has this year been updated to include an operator console featuring a TFT display. The first of the updated OGM 240s were installed on 150t capacity KZ-1572 railway cranes manufactured by Russian crane builder JSC Kirovsky Mashzavod.

Along with preventing the cranes from overturning, the OGM 240 series also features collision detection functions to assist crane operations in restricted working conditions, for instance in close proximity to overhead power lines.

Intended as a cost-effective, easy to maintain load moment indicator, the OGM 240 can be fitted to a variety of crane types, including mobile hydraulic and tower cranes.

Rezonans says its connection blocks and sensors can easily be replaced, as they are each connected using separate cables, and the real-time data logger also features an SD card port for easily accessible and transferable readouts.

Towards the end of this year, the manufacturer also intends to produce a lower cost variant of its BI04.70 TFT operator console with a USB port for the data logger, a feature which will be included in both the OGM 240 rated capacity indicator and the SBUC control system.

Loadwise International
Hampshire, UK-based Loadwise International has announced it will be releasing its latest load moment indicator, the 5000 LMI, in the last quarter of 2011.

Based on the functionality of the long-standing 500 series of load moment indicators, the 5000 LMI will be suited for use with knuckleboom, telescopic and lattice boom cranes, along with ship-to-shore, port, offshore and container handling cranes. It features an IP65-rated 45mm x 125mm digital LCD that displays four lines of text on an easy-to-read backlit screen. Data monitored by the 5000 LMI’s fully automatic microprocessor-controlled system includes the load radius, load weight as a percentage of the crane’s rated capacity, hoist drum selected—along with the number of falls of rope—boom angle and duty configuration.

Loadwise says this microprocessor represents a significant improvement on the 500 series, as it is faster, has double the memory, and manages the data flow from sensors in a more stable fashion.

The unit features eight analogue inputs for load, boom angle and boom length—along with four programmable relay contacts for boom synchronisation—and 10 outputs, four of which are undefined relay coil outputs.

The 5000 LMI also includes integrated optional features, such as the ‘virtual wall’ range limiting function, a wind speed indicator and a slew position monitor, facilitating the easy upgrade installation.

Loadwise says it can provide customised options for customers, with operator pre-configured limits that trigger audible and visual warnings occur when approaching overload conditions.

Loadwise’s 5000 LMI system is compliant with 93/68/EEC, 89/336 and 92/31/EEC, EN 50081-1:1992 and EN50082-1:1997 safety requirements.

Building on more than 30 years of SLI experience of the companies of PAT and Krüger and known for its innovative, precise, and reliable SLI solutions, Hirschmann has now set what it calls the next milestone in SLI for telescopic cranes: the Scalable Mobile Control System (SMCS).

New standards for the functional safety of machine applications require safety-related crane features, such as load moment indication, that comply with specific safety classes. To deal with compliance with international standards, on the one hand modules have highly-sophisticated software features (IEC

61508) and, on the other hand, they require a secure control platform in compliance with EN 13849, such as the Scalable Mobile Control System.

In order to increase the efficiency and competitiveness of crane manufacturers, Hirschmann has significantly reduced calibration times for its SMCS. Using a method mathematical modeling new to Hirschmann, the time required for calibration has already been significantly reduced to a minimum at the time of initial operation of the crane prototypes (about four hours depending on the crane type). For series production of telescopic cranes, typically the overload runs required to pass the operational tests of the TÜV inspection (in Germany) are enough to obtain the parameters for calibrating the crane. All that is left to do is balance the sensors.

The operator selects graphical elements that he can see and compare with his crane without the need for texts or language. In addition, a small symbol next to each key tells the crane operator what it does, ensuring language barriers or other confusing circumstances do affect the safety of the machines operation. This approach has made it possible to reduce the number of keys on the interface.

The accuracy of the SLI is also ensured in all special configurations, for instance with a folded-in tip or an attached tip with load on the main jib, without the need for additional calibration.

In addition, capturing and factoring in the cylinder friction for both dry and viscous friction optimizes the dynamic values for raising and lowering of the jib.

This makes it possible for the crane to lift heavier loads at the same radius, allowing the potential maximum loads in the lifting chart to be achieved more fully.

For example, if a crane can lift 30t at a certain position and the SLI only has an accuracy of 5%, it has to halt the crane at 28.5t. But if it has an accuracy of 1%, the SLI doesn’t need to trigger until a weight of 29.7t is reached. This allows the same crane to lift 1.2t more with no need for costly modifications.

All cutoffs are performed in a way that takes loads and motion into account to prevent hard cuts from causing dangerous machine reactions. SLI-controlled cutoffs are monitored afterward by checking the subsequent movements of the crane and if necessary executing an additional cutoff via a different path (safety CUT), namely by directly shutting down the hydraulic pumps.

Load Systems International
Load Systems International has introduced the new GS820 Load Moment Indicator (LMI).

The device features a pair of pressure transducers that read the rod and bore side pressures of the lift cylinders. Data from the transducers is transmitted wirelessly to the GS820 display.

The typical error rate seen by the system is 1% of maximum load capacity. Original equipment manufacturers will appreciate the ability to save the calibration data on the first machine to a USB thumb drive and load the calibration to subsequent machines via the onboard USB port. On the subsequent machines the calibration will require minor tweaking relative to the pressure variances of each machine, allowing for a simple, fast calibration.

The GS820 features a large sunlight readable graphical display, onboard data logger, ability to upload load charts via the onboard USB port or download the data logger via USB thumb drive. The display shows at a glance: all crane geometry, working load limit, actual load, selected chart/counterweights, wind speed, alarms and system faults.

LSI’s Load Moment Indicator System will be available in the USA on 15th September 2011 and will be available internationally by the beginning of December 2011.

At the start of 2012, Rayco-Wylie will be introducing a new LMI system to the market that will be usable by a variety of cranes, including boom trucks, telescopic and lattice boom cranes, along with crawlers and tower cranes. Targeted directly at crane manufacturers, the i4500 will be shipped pre-configured to each crane’s specifications, with its sensors and load cells pre-calibrated to each machine.

Rayco-Wylie says the new LMI system will feature a larger integral memory and a higher CPU processing speed than users will have previously experienced from the manufacturer, allowing the i4500s use with more complex crane functions.

Operator feedback will be through a high-resolution colour LCD, available in sizes ranging from a 4.3in screen to a 10.5in screen. Rayco-Wylie says the operator will easily be able to read the IP67-rated display screen even when it is in direct sunlight. Using this the operator can centralise vital information on the one screen for effective range limiting, including wind speed, outrigger positioning data, real-time camera views, boom sequencing information or engine data. Information obtained through data logging will be easy to transfer using a USB drive.

Designed for easy installation, setup and servicing, Rayco-Wylie says the i4500 consists of a smaller number of components than some of its predecessors. The unit will also feature CANbus technology for simplified after-service calibration. The i4500 is compliant with EN ISO 13849-1:2008 safety standards, leading a Rayco-Wylie spokesman to claim, “The i4500 is a complete Rated Capacity Indicator which will raise the bar on reliability, diagnostic capability and analysis of safety function performance.”

Load Systems International Load Systems International
Rezonans Rezonans
Hirschmann Hirschmann
Rayco-Wylie Rayco-Wylie
Loadwise International Loadwise International