Signal Concept, PSM, Function - GF54.21-D-2000TSB

Model 447, 448 

With Code ED5 (Parameterisable special module) 

With Code XM7 (MOPF II) 

Model 907, 910 

With Code ED5 (Parameterisable special module) 

With Code XJ4 (Modification year G4-I) 

Signal flow in parameterizable special module (PSM) control unit (N26/16) 

Courtesy of MERCEDES-BENZ USA

Function overview and brief description of signal pool 

The signal pool contains signals for free use by the customer and for internal functions. The signal sources are:

• Values of internal functions
• Constants (e.g. for bits bytes)
• Status of multifunction inputs and multifunction outputs
• Results of programmable logic controller (PLC)
• Results of arithmetic unit
• CAN signals of the CANs connected to the parameterizable special module (PSM) control unit (N26/16):
  • CAN signals of the interior CAN (CAN B)
  • CAN signals of CAN 2 for user interface (model 907, 910) or user interface CAN 2 (model 447, 448) (CAN HMI2)
  • CAN signals of bodybuilder manufacturer CAN (CAN ABH)
  • CAN signals of multifunction CAN (model 907, 910) or CAN for multifunctions (model 447, 448) (CAN K)

The signals are available as a bit, byte, data word ("Word") (2 bytes), double word ("DWord") (4 bytes), signed word ("signed Word") (2 bytes) and signed double word ("signed DWord") (4 bytes). Every signal has a unique 2 byte identification number of the signal, which is referred to as the signal ID.

Each signal has one single source, but it can be used as often as necessary by the internal modules of the parameterizable special module (PSM) control unit (N26/16). The signal pool is specific to the model series.

Signal pool input 

Each signal has just one source.

Signal pool output 

Each signal can be assigned to e.g. one or more outputs by means of parameterization and used internally. Individual signals can be dependent on other signals, e.g. terminal 15.

Status display 

The value of each signal can be shown through the "Display signal values" menu item in XENTRY Diagnosis. The menu item is available in the "Actual values" tab and in the expert coding.

Special signals 

The following special signals exist:

• "Permanent low" signal: gives a logical "0" at the input at which the signal is applied.
• "Permanent high" signal: gives a logical "1" at the input at which the signal is applied.
• "Prompt deactivated" signal: deactivates the prompt for this input.

Overview of system components for parameterizable special module (PSM)

GF54.21-D-9998TSB