CLG-D Load Limiter Control Unit has been designed to measure the differential pressure of the hydraulic cylinder of the first boom. The pressure readen is always the difference between the pressure of the two chambers of the cylinder: the bottom chamber (or cap end) and the piston rod side chamber (or rod end). To have an accurate pressure measurement it is necessary to know the area ratio of the piston.

The green led on the board, in normal operation mode, is lighten to show the power supply. When faults are present, the green led blinks following a particular sequence related to the fault reasons. (look at the last page for a detailed blinking sequence meaning).

Also, it is present a LED bargraph to show the load percentage in real time, compared to the maximum load.When the load exceedes the 100% of the limit, red LED of the bargraph blinks.

In RESET condition, it is not allowed that the differential pressure increases; if this occurs, the ELV1 output is blocked before the end of the standard RESET time. This function can be disableb by the crane manufacturer with a PC serial connection software. 

Leds placed into the emergency button box (red colour and yellow colour), are lighten in the following situations:

- When emergency button is pressed, the red button and the yellow button blink together.

- When the load exceedes the 90% of the limit, yellow led is ON.

- When the load exceedes the 100% of the limit, red led is ON.

Input

- RESET: That input allows the load limiter to power the valve for a short period, even if the load value exceedes the load limit.

- LIMIT REDUCTION: It is used to set the working area. When it is low value, then the load limiter compare the pressure from the transducer with a reduced threshold.

- 2 PRESSURE transducer inputs: 4 In the respect of EN 954-1 the safety features belong to category 2 hydraulic cap end). The Pressure Transducer no.2 (cable 6) must be installed in the the piston rod side chamber (rod end). This is requested for the good working of the CLG-D Load Limiter. When the load exceedes the 100% of the limit, red LED of the bargraph blinks. In RESET condition, it is not allowed that the differential pressure increases; if this occurs, the ELV1 output is blocked before the end of the standard RESET time. This function can be disableb by the crane manufacturer with a PC serial connection software. ÷20 mA.

- INPUT DV: It allows to connect the load limiter to a remote control in a safety way.

- DIFFERENT POWER SUPPLY for logic control unit and powered OUTPUT. 

Output

- Powered output to drive bypass valve coil. The board implements a feedback current control on the mentioned output.

- Two powered output to drive external optional lamps. The mentioned outputs are driven as well as the leds into emergency button box (90% and 100%).