DIGITAL OUTPUTS

The VCU has 10 digital output pins, seven low side and three high side. The PLD-MR has five digital outputs. The VCU digital output functions and their associated pins are listed in Table 4-14.

Digital Output Function Driver VCU Connector/Pin

Vehicle Power Shutdown Low Side 18/01

Engine Brake 1 Decompression Valve High Side 15/10

Grid Heater Control High Side 15/10

Wait to Start Lamp Low Side 21/07

Gear Out 1 High Side 15/05

Oil Level Lamp Low Side 21/04

Starter Lockout Low Side 15/12

Amber Warning Lamp Low Side 21/06

Red Stop Lamp Low Side 21/05

Table 4-14 Digital Outputs

4.4.1

VEHICLE POWER SHUTDOWN

This digital output actuates a relay that shuts down the rest of the electrical power to the vehicle when an idle shutdown or engine protection shutdown occurs. For additional information, refer to section 5.8, “Idle Shutdown.”

This function is available with the VCU only.

Installation

This digital output circuit is designed to sink no more than 2 A (DC) current. The Accessory Bus Shutdown is wired to pin 18/01 of the VCU.

4.4.2

GRID HEATER CONTROL

This digital output controls the relay for the Grid Heater.

Installation

This digital output circuit is designed to source no more than 2.5 A (DC) current. The Grid Heater Control digital output is wired to pin 15/10 of the VCU.

Programming Requirements and Flexibility

This digital output is automatically configured when the Cold Start configuration is enabled.

4.4.3

WAIT TO START LAMP

This digital output is switched to battery ground when the Wait to Start (Cold Start) system is active. This output is used to drive a light to alert the operator. As long as the lamp is illuminated the engine should not be started.

Installation

A 12 or 24 volt lamp of less than 500 mA DC is needed depending on the ignition source. This digital output circuit is designed to sink no more than 500 mA (DC) current.

4.4.4

GEAR OUT 1

The AT500 and MT600 transmissions require a throttle position input from the engine in order to get an indication of the current power level at any given time. This input is used to raise the shift points and apply the clutches more firmly with increasing engine power.

The MBE 900 engine needs to provide a digital output that switches high (Vbatt) under certain conditions and switches open (strike through or low [ground]) under other conditions. When switched high, the output needs to have the ability to source 0.5 amps minimum when using a relay or 3 amps minimum if driving the modulator directly.

When Cruise Control and Road Speed Limiting are not active:

If the Gear Out 1 output is enabled, it will be disabled (open [strike through or low]) if the engine is not running or the accelerator pedal position is <45%.

If the Gear Out 1 output is disabled, it will be enabled (switched high) when the engine is running or the accelerator pedal position is >60%.

When Cruise Control is active or near the road speed limit:

If the Gear Out 1 output is enabled, it will be disabled if the engine is running and the accelerator pedal position is >60%

If the Gear Out 1 output is disabled, it will be enabled when vehicle speed is within one (1) mph of the cruise set speed or road speed limit speed or the percent load at the current speed is >80%.

Installation

This digital output circuit is designed to sink no more than 1 A (DC) current. The Gear Out 1 digital output is wired to pin 15/05 of the VCU.

4.4.5

OIL LEVEL LOW LAMP

This digital output is switched to battery ground when the oil level falls below the oil fill threshold as read by an Oil Level Sensor. This output is used to drive a light to warn the operator. The AWL will illuminate when an oil level fault is logged in the VCU.

Installation

A 12 or 24 volt lamp of less than 500 mA DC is needed depending on the ignition source. This digital output circuit is designed to sink no more than 500 mA (DC) current.

4.4.6

STARTER LOCKOUT

This digital output drives a normally closed relay which interrupts the starting signal when the output has been activated. For additional information, refer to section 5.11, “Starter Lockout.”

Installation

This digital output circuit is designed to sink no more than 2.0 A (DC) current. The Starter Lockout digital output is wired to pin 15/12 of the VCU.

4.4.7

AMBER WARNING LAMP

The Amber Warning Lamp is illuminated for all active faults. The AWL will also flash when an engine shutdown occurs.

Installation

This digital output circuit is designed to sink no more than 300 mA (DC) current. The AWL is wired to pin 21/06 of the VCU.

NOTE:

This digital input is REQUIRED.

4.4.8

RED STOP LAMP

The Red Stop Lamp (RSL) is illuminated for all active serious faults, which require the engine to be shutdown immediately. The AWL will also flash when an engine shutdown occurs.

Installation

This digital output circuit is designed to sink no more than 300 mA (DC) current. The RSL is wired to pin 21/05 of the VCU.

NOTE:

5

FEATURES

Section Page

5.1 ANTI-LOCK BRAKE SYSTEMS ... 5-3