Digital Tachograph (DTCO), Function - GF54.61-D-0003TSA

Model 907 

with code J05 (Tachograph, Latin America) 

Model 907 

with code J19 (Tachograph 1 day/2 drivers automatic (CM)) 

Model 907 

with code JD2 (Tachograph digital EC with RPM + aux-recorder) 

Block diagram 

Digital tachograph (DTCO), general 

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

• Date
• Time
• Vehicle speed
• Travel distance
• Mode
  • Wheel time
  • Other working hours
  • Break and idle periods
  • Standby times (waiting times, co-driver times)
• Fault recording with fault code

The language displayed is automatically determined by the driver card currently or last inserted.

The digital tachograph (DTCO) includes the following subfunctions:

• Press any button of digital tachograph (DTCO).
• Event or fault message
• Signals via multifunction CAN (CAN K) from and to parameterizable special module (PSM) control unit (N26/15) with code ED5 (Parameterizable special module)

Function sequence for "ignition ON" 

At "Ignition ON" the following information is shown on the display:

• Time
• Vehicle speed
• Travel distance
• Mode
• If a driver card is not inserted in card slot 1, an appropriate message is shown for 20 s.

Function requirements for recording journey data 

• Ignition "On"
• At least one driver card inserted into digital tachograph (DTCO)
• Function sequence for "ignition OFF"
• Function sequence for "ignition ON"
• Function sequence for recording journey data

Function sequence for "ignition OFF" 

At "Ignition OFF" the following information is shown on the display of the digital tachograph (DTCO):

• Time
• Vehicle speed
• Travel distance
• Mode

After approx. 5 min, the digital tachograph (DTCO) switches to the standby mode; after another 3 min, the display goes off.

The standby mode is canceled through the following actions:

• Ignition "On"

Function sequence for recording journey data 

The digital tachograph (DTCO) control unit receives a conventional signal from the tachograph speed sensor (B158) via a direct line, and also receives an encrypted signal via another direct line. The digital tachograph (DTCO) compares these signals and by doing so it can recognize any manipulation.

In addition to the signal from the tachograph speed sensor, the digital tachograph (DTCO) control unit receives an independent comparison signal from the ESP® control unit (N30/4) via the suspension FlexRay (Flex E), the electronic ignition lock (EZS) control unit (N73/8), the user interface CAN (CAN HMI), the instrument cluster (A1) and the tachograph CAN (CAN TCO).

After evaluating the signals, the following data is shown on the display of the digital tachograph (DTCO):

• Time
• Vehicle speed
• Travel distance
• Mode
• Activity of driver 1 or 2
• Card symbol of driver 1 or 2

Provision of DTCO data for other systems 

Signals via multifunction CAN from and to PSM control unit (with code ED5 (Parameterizable special module)): In this case, the parameterizable special module acts as a gateway, e.g. for FleetBoard applications.

Electrical function schematic of digital tachograph (DTCO)	PE54.61-D-2050-97TSA
Overview of system components for digital tachograph (DTCO)	GF54.61-D-9999TSA