REMOTE CONTROL AND TANDEM CRANES
Handling and lifting large material and heavy loads may need simultaneous lifting by two cranes (even three / four cranes) or trolleys controlled at the same time. When cranes work in this mode, it is said that they are operating in “tandem mode“. Usually, the cranes are controlled by the same remote control for easier operation and a more ergonomic control. It, therefore, acts as a master transmitter.
At any time the operator can choose the desired trolley or crane to be controlled, from the most appropriate location with a better field of view and the necessary safe distance.
For a safe operation of cranes in tandem mode without disruption of the communication between the cranes, the safety of the system must be guaranteed at all times. To ensure this level of safety wireless operating systems must comply with the EU-guidelines.
Usually, when a crane or trolley reaches the first limit switch it will go from fast to slow speed in synchronization with the rest, when the last limit switch is activated, the application will stop immediately. Both cranes must always be synchronized to ensure that the load being lifted does not falls down and the operator do not suffer any accident. This way of safety can also be applied to a hoist in case of reaching the load limit in lifting. The lifting limit is not exceeded by activation of the limit switch.
The Tele Radio Tiger-Lynx system for tandem function complies with the European standard EN15011:2011-05, which specifies that for lifting in tandem mode the application must be intercommunicated in all their movements.
Examples of common applications
2 EOT Cranes – 1/2/1+2 Mode
In this mode, there are two wireless transmitters and two receivers (one for each crane). One of the transmitters is configured as a master and the other as a slave, the same applies to the receivers.
The user can choose the crane he wants to operate individually, or can use the master transmitter to work in tandem mode, that is, to be able to control both cranes. When any of the signals are activated (by speed/end limit switch or by overloading the hoists, for example), it will immediately communicate to the 2nd receiver to stop, resulting in both cranes stopping instantly.
3 EOT Cranes – 1/2/3; 1+2; 2+3 Mode
Another situation that requires an advanced and inter-communicated system is when we add a third crane in the same factory for such intended application. This is necessary when the loads to handle are even greater in dimensions and/or higher in weight. Commonly found at windmill blades tandem lifting. Each crane requires its standard equipment, with a transmitter and a receiver. Equipment #2 (the central position in the building) is configured as master, since it will be the most used one in any of the cases in tandem.
The user will be able to select the desired crane to work individually, but also can use the master transmitter at any time to work in tandem mode to control 1 + 2 (crane # 1 + crane # 2) or 2 + 3 (crane # 2 + crane # 3). To do this properly and safely, it is necessary that the slave transmitters of cranes 1 and 3 respectively have logged out accordingly. It will never be able to control a crane with two transmitters at the same time, due to the intrinsic safety of Tele Radio’s Tiger remote control equipment and its high level of safety.
Note for installers: In both cases, regarding the installation of the equipment, it must be taken into account that an external electrical panel for each crane has to be mounted, including potential-free relays that will receive the limit switches or the overload signals from the crane installation. The recommended location for the installation of the external panel would be outside the control panel, to avoid possible noise and electrical interferences.
The overall result in combination with the advanced technology and components used are really impressive. A solution that has proven to be robust at hundreds of factories around the world and that the market is increasing its demand every year.
Do you want to know more about this solution? Contact us.
The Swedish Tele Radio Group has been operating – safe, smart and strong – in the wireless remote-control market for more than sixty years. Various systems have been independently tested and certified to meet the requirements in accordance with SIL3, PLd and CAT3.
Thanks to Toronto Electric & CPC Pumps for providing the pictures of their cranes working tandemly with Tele Radio Systems.