SUPPORT ASSEM. 5L8887 - Caterpillar

Engine: 3616 (S/N: 1FN; 1PD) 3618 (S/N: 2MW)Introduction
The 150-7700 Tachometer/Speed Switch is generally used to control the opening and the closing of the bypass solenoid valve. This tachometer/speed switch is installed on the 3616 and on the 3618 for the Fast Ferry Ratings. This Special Instruction contains the information that is needed in order to install the tachometer/speed switch. This Special Instruction also shows the operation of the tachometer/speed switch. Do not perform any procedure in this Special Instruction until the entire instruction has been read and understood.The tachometer/speed switch continuously measures the engine speed with a magnetic pickup that is connected to a ring gear on the flywheel. The tachometer/speed switch also stores four setpoint values and the information for the setup of the gauge in a nonvolatile memory. An LCD display is used to display the following information: the numeric value, the units of rpm, the state of the output switches and a bar graph. The monitored rpm is continuously compared against the four adjustable setpoints. Multiple points of overspeed shutdown are permitted with this configuration and multiple points of underspeed shutdown are also permitted. The tachometer/speed switch is also used for various purposes such as giving speed signals to the control system for the gear box.Each setpoint can be individually configured to a high point or a low point. The setpoints can also be configured to the normally open position or the normally closed position. In addition, each setpoint can be individually adjusted for the following parameters: a value for the hysteresis, a time delay trip and a reset delay time. The operator can also control the following parameters: the programmable input pulse count, the ratios for the input that can be changed according to a scale, the rpm indicator (the indicator can be turned off for other measurements of rate), a decimal point that can be set and the ability to accept inputs from uneven patterns. Also, the LCD contains a bar graph that can be programmed for the bar mode or for a single bar between two selected points. A programmable software display filter is also incorporated in order to stabilize the readings of the variable signal from the input. The output of the current loop (4 mA to 20 mA) of the 150-7700 Tachometer/Speed Switch can also be configured through the keypad. The current loop can be configured anywhere within the range of the gauge and in the range of the reverse acting. If the output of the current loop (4 to 20 mA) is configured for reverse acting, the current output would decrease or the current output would approach the point of 4 mA. The numeric value of the rpm on the display would increase with the change of the current output.Signal Input
The 150-7700 Tachometer/Speed Switch is designed to accept signals with a wide range of frequencies. These signals have an amplitude of 5 to 400 volts peak. The frequency of these signals is 0.5 kHz to 20