Model 4700 Maintenance Manual

Section 8.Theory of Operation

Systems Overview System Architecture

Systems Overview

This section is an overview of the components that make up the control systems of the truck. See “Pinout Matrix” beginning on page8-14 for specific input, output, and voltage information.

Vehicle Manager

The Vehicle Manager (VM) provides several functions. It interfaces with the travel direction switches and travel potentiometer. The VM stores the learned values for the travel and lift potentiometers. It also stores the learned values for the lift and travel potentiometers as well as default configuration values. With the standard spool valve hydraulic controls, lift/lower, sideshift, tilt, 4th, and 5th auxiliary function switch/potentiometer requests are input directly to the VM. The VM distributes 24V power to the operational and working lights on the truck. It also contains the circuits that activate the brake and tail lights based on inputs from the TPA. Refer to “Hydraulic System” on page8-8 for specific information on the operation of standard and optional hydraulic systems.

Traction Power Amplifier

Dual Traction Motor Trucks

The Traction Power Amplifier (TPA) is a Dual AC Motor Controller. The TPA contains two separate controllers within a single unit with outputs for two separate AC motors. The controllers are designated as Master and Slave. The Master controls the right traction motor and the Slave controls the left traction motor. The Master and Slave communicate with each other internally as well as externally with other devices connected to the CAN-Bus. Requests for travel direction and speed are communicated from the VM via the CAN-Bus. The TPA generates an RPM request to the traction motors to comply with the travel request. It then monitors motor operation and adjusts the command voltage to the motors to maintain motor performance equal to the request. The TPA receives an input from the steer potentiometer and regulates traction motor

Publication 1160093, Issued: 20 May 2013 direction and speed with regard to steer wheel angle. It stores the learned value for the steer potentiometer. Motor parameters such as acceleration, speed limiting, motor braking, motor current, and creep speed can be configured with FlashWare and are stored in the TPA. The TPA also stores the learned values for the steer potentiometer. The Master and Slave are capable of generating error codes. See “Codes” on page6-4.

Single Traction Motor Trucks

The Traction Power Amplifier (TPA) is an AC Motor Controller. Requests for travel direction and speed are communicated from the VM via the CAN-Bus. The TPA generates a command voltage to the traction motor to comply with the travel request. It then monitors motor operation and adjusts the RPM request to the motor to maintain motor performance equal to the request. Motor parameters such as acceleration, speed limiting, motor braking, motor current, and creep speed can be configured with FlashWare and are stored in the TPA. The TPA is capable of generating error codes. See “Codes” on page6-4.

Pump Power Amplifier

The Pump Power Amplifier (PPA) is an AC motor controller that controls the motor used to provide hydraulic power for all hydraulic functions. The PPA communicates with other devices via the CAN-Bus. Requests for all hydraulic functions (including steering) are communicated to the PPA via the CAN-Bus from the VM or from the Armrest Board (fingertip control configurations). The PPA then generates an RPM request to the pump motor. Pump motor operating parameters may be different for the various hydraulic functions. Parameters such as delay, maximum speed, and maximum motor current can be configured with FlashWare and are stored in the PPA. The PPA is capable of generating error codes. See “Codes” on page6-4.

Amplifier Fan

The truck is equipped with a cooling fan for the TPA and PPA. This fan should energize within

Section 8.Theory of Operation

Model 4700 Maintenance Manual System Architecture Systems Overview

about one minute of turning the key ON. This is accomplished by a drive signal from the VM to the fan. If this fails to occur, the TPA and PPA could overheat.

DC/DC Converter

A DC/DC converter provides 24V to the lights, cooling fan, solenoid valves, and so on. It also provides 24V to the Hydraulic Control Board on trucks with the Fingertip Controls option. A dedicated 12A fuse is located on the end opposite the connector.

Operator Display

The Operator Display (OD) receives communications from the CAN-Bus and 24V power from the VM. Various icons illuminate to inform the operator of the status of the truck. The OD also displays hour meters and Battery State-of-Charge (BSOC), however BSOC is calculated by the Master TPA. The OD also contains a two position alphanumeric display that provides error and status code information. See “Operator Display Messages” on page6-2.

Armrest Board

The truck can be equipped with optional Fingertip hydraulic controls that are located on the armrest on the right side of the operator’s seat. The Armrest Board receives inputs from the fingertip hydraulic function controls based on operator input. Hydraulic output flow is controlled by proportional and solenoid valves instead of the spool valves used on the standard hydraulic system. The Armrest Board processes the request and informs the Hydraulic Control Board which solenoids to energize and the PPA to energize the pump motor, providing the hydraulic flow necessary for the given function. The Armrest Board can also initiate error codes for the components (potentiometers and switches) that it interfaces with. See “Codes” on page6-4.

Hydraulic Control Board

The Hydraulic Control Board is a hydraulic driver board that receives commands via the CAN-Bus from the Armrest Board. It contains coil drivers for the hydraulic solenoids and is required for the optional Fingertip controls. The Armrest Board communicates hydraulic function requests to the Hydraulic Control Board, which energizes the solenoids. The parameters regarding the operation of the solenoid valves that the Hydraulic Control Board controls can be adjusted and set in FlashWare. The Hydraulic Control Board can initiate error codes in the coil circuits that it controls. See “Codes” on page6-4.

Ct1

CT1 provides B+ to the DC/DC Converter and Hydraulic Control Board (for optional Fingertip Controls). The CT1 contactor coil is designed to operate on approx. 36V. Because these trucks accept both 36V and 48V batteries, voltage to CT1 from a 48V battery must be reduced. This is accomplished via a control relay (RL1) that is energized when the key switch is turned ON.

When a 48V battery is installed in a truck configured (via FlashWare) for a 48V battery, RL1 is energized. The RL1 contact tips open, redirecting current through a 56 ohm resistor wired in parallel with the RL1 contact tips. The 56 ohm resistor reduces the voltage approx. 8V, thus providing approx. 40V to the CT1 contactor coil.

When a 36V battery is installed in a truck configured (via FlashWare) for a 36V battery, RL1 is not energized. The RL1 contact tips remain closed, causing current to bypass a 56ohm resistor wired in parallel with the RL1 contact tips, thus providing B– to the CT1 contactor coil.

Ct2

CT2 provides B+ to the PPA. This is a 36/48V contactor which is supplied 24V PWM.

Publication 1160093, Issued: 20 May 2013