Advantest A000824B-DED BGR-022365 card

Various manufacturers have different systems for bus termination. The RS485 standard does not describe how the “Fail Safe” function would be carried out, just that the system should be able to handle the error.Depending on the recipients’ design, the bus wires may be on the same level or require pull-up or pull-down to ensure that no faulty signals are detected when the bus is in resting mode (all transmitters are disconnected)

1. Some (older) operator panels had pull-up and pull-down resistance except for the actual bus termination at 120 ohm, similar to Westermo and Profibus. 

2. Newer panels have another type of recipient, so-called built-in “Fail Safe”, where simple bus termination resistance is sufficient. If other nodes on the RS485 network require pull-up and pull-down and the operator panel is at one end of the loop, one of the following procedures can be carried out:

3. Connect two 1 ohm/0.25 W resistors in the 25-pole D-sub contact. Set jumper pins 6-19.

DESCRIPTION

 The 512/524 and 1712/1724 EPGs are three-component governing systems for 12 or 24 Vdc operation. All EPG systems include an actuator, an electronic speed control, and magnetic pickup. Isochronous electronic controls are available with either start-fuel limit or with switch-selected dual dynamics. Droop controls are available for certain types of parallel generator application. Load sharing devices are available for use with the isochronous models used in paralleled applications.

The selected EPG actuator is mounted 

on the prime mover and mechanically linked to the fuel control. The rotary design and output shaft on both ends gives 30° (512/524) or 35° (1712/1724) clockwise or counterclockwise travel to low-mass, lowfriction fuel linkages. Preloaded internal return springs supply the shaft torque in the decrease-fuel direction and for shutdown should the electronic control signal be lost. A rugged cast aluminum housing permits installation of the speed control on the engine skid. In operation, the control compares the speed of the engine with the desired speed or desired load and sets the actuator position to correct discrepancies.