Technical information

DRV Operator’s Manual and Technical Reference (rev 1 0 June 30, 2000)

B.1 Introduction

The DRV utilizes an industrial controller. The controller has two types of inputs, analog

and digital. The analog inputs are accomplished via the analog to digital (A-D)

expansion board. The A-D board converts a varying input voltage into a digital integer

value that the controller can use to evaluate signal amplitude. As an example, +5 Volts

may be represented as the integer value 2048 in software. Likewise, there are two types

of outputs, digital and analog. The analog outputs are accomplished via the digital to

analog (D-A) expansion board. The conversions are done in hardware and interpreted in

software. Digital inputs and outputs (IO) are accomplished with the digital IO interface

on the controller and the digital IO expansion board. The digital I/O utilizes Transistor-

Transistor Logic (TTL). Voltage readings should always be done with a digital

voltmeter. Using a test light or jumpers could cause damage to the controller. A

qualified person should be dedicated to the emergency stop switch before any testing is

conducted.

B.1.1 Analog Inputs

The joystick and position sensor inputs are the only analog inputs on this control system.

The joystick and position sensor data can be verified by utilizing the controller. Press the

menu button until the Display Control section is selected. Then use the up/down arrows

to select either the joystick or coords for the position sensors. The menu button then must

be pressed until the default screen is again displayed. The inputs can now be viewed.

This not only guarantees that the input devices are working but that the controller is

interpreting the data. If the display indicates that the input device is not working then the

raw data can be checked. The analog inputs all range from 0 to +10 VDC. Joystick

inputs can be checked with the engine off and the controller running. The position sensor

inputs can be measured the same way however, no change can be observed. The position

sensors are calibrated and should not be changed; Therefore, the hydraulic system should

be running with the arm deployed on the opposite side of the vehicle from the controller

so that the input can be safely measured as the joints move. Position sensor inputs can be

measured from the terminal strip of the signal conditioning board located in the center of

the controller and can also be observed via the LCD display.

B.1.2 Digital Inputs

The digital inputs are used for the toggle and limit switches. The controller input is

normally high, +5 VDC, and then pulled low via a switch. For example when a switch

contact is open, the conductor coming from the controller will measure a +5 VDC

potential referenced to ground. When switched the input is pulled low, to ground, the

input is considered active.

Warning !!!

Never connect any voltage source to the digital inputs, damage to controller will occur.

Inputs are only switched to ground.

The digital inputs of the controller are normally high, nominally +5 VDC. The +5 VDC

supply is integral to the controller and pulled high via an internal pull up resistor. In this