Digital Tachograph (DTCO), Detailed Information - GF54.61-S-0004A

Model 447.6/7 

With Code J4V (Pre-installation of EU intelligent tachograph) 

With Code JD6 (Intelligent tachograph, EU) 

With Code XM7 (MOPF II) 

Courtesy of MERCEDES-BENZ USA

Overview of digital tachograph (DTCO), shown on model 447.6/7 

Topology of digital tachograph (DTCO), shown on model 447.6/7 

Courtesy of MERCEDES-BENZ USA

Overview 

This document contains information on:

• General 
• Function requirements 
• Function 
  • Function sequence for ignition switched OFF 
  • Function sequence for ignition switched ON 
  • Function sequence for moving vehicle 

General 

The digital tachograph control unit (DTCO) (A56) is recording equipment required by law for recording the following data for a maximum of 2 drivers:

• Date
• Time
• Vehicle speed
• Distance
• Total distance
• Time groups
  • Driving time 
  • Other working hours 
  • Break and rest periods 
  • Standby times (waiting times, passenger time) 
• Fault recording with fault code

The displayed language of the digital tachograph control unit (DTCO) (A56) is automatically determined by the current or last inserted tachograph card.

Function requirements 

• For vehicles in motion:
  • At least one tachograph card inserted in digital tachograph control unit (DTCO) (A56)
  • Digital tachograph control unit (DTCO) (A56) not in standby
  • Vehicle speed > 0 km/h

Function 

The DTCO has the following subfunctions:

• Function sequence for ignition switched OFF 
• Function sequence for ignition switched ON 
• Function sequence for moving vehicle 

Function sequence for ignition switched OFF 

In case of ignition switched OFF, the following information is shown on the display of the digital tachograph control unit (DTCO) (A56):

• Time
• Speed (0 km/h)
• Total distance

After approx. 5 min, the digital tachograph control unit (DTCO) (A56) goes into standby. The time, operating mode and activities that are set are shown on the display. After a further 3 min, the display turns off.

The standby mode is canceled through the following actions:

• "Tml. 15 ON"
• Actuating any button on the digital tachograph control unit (DTCO) (A56)
• The digital tachograph control unit (DTCO) (A56) reports an event or a fault.
• Signals via multifunction CAN (CAN K) from and to parameterizable special module (PSM) control unit (N26/16) with code ED5 (Parameterizable special module)

Function sequence for ignition switched ON 

In case of "ignition switched on", the following information is shown on the display:

• If there is no card in card slot 1, the message "Card!" appears for 20 s
• Time
• Speed (0 km/h)
• Total distance

Function sequence for moving vehicle 

The digital tachograph control unit (DTCO) (A56) receives a conventional realtime signal and encrypted data (from the cryptography microchip integrated into the speed Hall sensor (B6)) via a direct line from the speed Hall sensor (B6). The digital tachograph control unit (DTCO) (A56) compares these signals and data and can thus reliably determine manipulation. At the same time, the digital tachograph control unit (DTCO) (A56) transmits data and command signals to the speed Hall sensor (B6).

Comparison of the serial numbers between the speed Hall sensor (B6) and the digital tachograph control unit (DTCO) (A56) also increases safety.

In addition to the speed signal of the speed Hall sensor (B6), the digital tachograph control unit (DTCO) (A56) receives an independent speed signal from the Electronic Stability Program (ESP) control unit (N30/4) via the suspension FlexRay (Flex E), electronic ignition lock (EZS) control unit (N73/8), user interface CAN 2 (CAN HMI2), instrument cluster (A1) and tachograph CAN (CAN TCO).

After evaluating the input signals, the following data are shown on the display of the digital tachograph control unit (DTCO) (A56):

• Operating mode (symbol)
• Speed
• Activity of driver 1 or 2
• Card symbol for driver 1 or 2
• Time

  The digital tachograph control unit (DTCO) (A56) receives the displayed time from the instrument cluster (A1) via the tachograph CAN (CAN TCO).

  • "UTC" time
• Total distance

Provision of DTCO data for other systems 

Signals via the multifunction CAN (CAN K) from and to the parameterizable special module (PSM) control unit (N26/16) (with code ED5 (Parameterizable special module)): The parameterizable special module (PSM) control unit (N26/16) serves as a gateway, e.g. for fleetboard applications in this case.

	Detailed information
	Overall network (GVN), detailed information	Model 447.6/7 with code J4V (Pre-installation for EU intelligent tachograph) with code JD6 (EU intelligent tachograph) with code XM7 (Facelift II)	GF00.19-S-0020-01B