LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mercedes Benz >> 2021 >> Metris Van Cargo >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Electrical System, Equipment & Instruments (05 Of 11) -- 447 Chassis >> Basic Knowledge >> PSM Logic Functions, Threshold Switch Function - GF54.21-D-3209TSB
April 5, 2026: LEMON Manuals is launched! Read the announcement.

PSM Logic Functions, Threshold Switch Function - GF54.21-D-3209TSB

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) 

G16501235Courtesy of MERCEDES-BENZ USA

Threshold switch, function 

The threshold switch has an analog input (E) with 16 bit width and 4 digital outputs (AA , AB , AC , AD ). The input (E) is an encodable filter connected in series.

A voltage is applied at the analog input (E) (e.g. 17.3 V); this analog voltage is converted into a (digital) numerical value (16 bit) using the A/D converter contained in the analog input (E).

The input value is compared with up to 4 threshold values (A, B, C, D) and then the relevant output set (AA , AB , AC , AD ).

The user can define these threshold values (A, B, C, D) themselves. If a threshold value is exceeded, the value of the associated signal changes from 0 to 1 (1 bit).

When coding the threshold switch, the parameter threshold value (PSA , PSB , PSC , PSD ) must match the following coding specification:

Threshold value (A) < Threshold value (B) < Threshold value (C) < Threshold value (D).

If this coding specification is not followed, the characteristic of the threshold switch is not defined.

For outputs (AA , AB , AC , AD ) a run point or a bar graph function can be coded. IMPORTANT Signal identification number = Signal ID.

SEQUENTIAL POINT FUNCTION

Input (E) Output (AA ) Output (AB ) Output (AC ) Output (AD )
Input (E) ← Threshold value (A) 0 0 0 0
Threshold value (A) < Input (E) ← Threshold value (B) 1 0 0 0
Threshold value (B) < Input (E) ← Threshold value (C) 0 1 0 0
Threshold value (C) < Input (E) ← Threshold value (D) 0 0 1 0
Threshold value (D) < Input (E) 0 0 0 1
BAR GRAPH FUNCTION

Input (E) Output (AA ) Output (AB ) Output (AC ) Output (AD )
Input (E) ← Threshold value (A) 0 0 0 0
Threshold value (A) < Input (E) ← Threshold value (B) 1 0 0 0
Threshold value (B) < Input (E) ← Threshold value (C) 1 1 0 0
Threshold value (C) < Input (E) ← Threshold value (D) 1 1 1 0
Threshold value (D) < Input (E) 1 1 1 1
CODING VIA DATA ENTRY TABLE

Designation in data entry table Data entry bit width Data bit evaluation Meaning
B1_G1_SS1 Schwelle_A [...threshold_A] 16 bit - Encodable threshold value (A)
B1_G1_SS1 Schwelle_B [...threshold_ B] 16 bit - Encodable threshold value (B)
B1_G1_SS1 Schwelle_C [... threshold_C] 16 bit - Encodable threshold value (C)
B1_G1_SS1 Schwelle_D [... threshold_D] 16 bit - Encodable threshold value (D)
B1_G1_SS1 Modus [B1_ G1_SS1_Mode] 1 bit - Set value: Bar graph → 0 Sequential point → 1
B1_G1_SS1_Signal_ID 32 bit 16 bit Filter + signal-ID input signal data entry
SIGNAL ID OF OUTPUTS

Designation in signal ID list Data bit width Meaning
SPS_G1_SS1_A 1 bit Signal ID of output (AA )
SPS_G1_SS1_B 1 bit Signal ID of output (AB )
SPS_G1_SS1_C 1 bit Signal ID of output (AC )
SPS_G1_SS1_D 1 bit Signal ID of output (AD )

The same applies for the other threshold switches with the naming conventions:

  Overview of system components for parameterizable special module (PSM)   GF54.21-D-9998TSB