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PSM Arithmetic, Example Of PSM Function - GF54.21-D-3055-01TSI

Model 447, 448 

with code ED5 (Parameterisable special module) 

with code XM7 (MOPF II) 

Speed signal, differentiate, integrate 

Model 907, 910 

with code ED5 (Parameterisable special module) 

with code XJ4 (Modification year G4-I) 

Speed signal, differentiate, integrate 

G16501230Courtesy of MERCEDES-BENZ USA

Vehicle speed signal function blocks 

The vehicle speed signal (interior CAN (CAN B): "VehSpd_Disp") can be output at one of the pulse-width-modulation-compatible outputs.

Formula: Pulse [1/s] = (Speed [km/h] * 4 [Pulse/m])/3.6

Value range for vehicle speed 4 to 409.4 km/h
Value range of pulse-width-modulated signal 0 to 100%
Pulse length 200 Hz

4 pulses/m are output. The pulse width is 4 ms.

At 112.5 km/h, the pulse duration is the same as the pulse pause. This 1:1 ratio is maintained up to higher speeds.

In other words, at higher speeds, the pulse length and pause length shorten at the same rate.

The speed signal is implemented via the blocks of the programmable logic controller (PLC), arithmetic unit and multifunction output blocks. The picture shows the simplified function block operation.

The configuration is available in the tables.

Function description of implementation 

Comparator 2, calculation step 1 (Comp 2): 

Arithmetic block 3, calculation step 2 (Calc 3): 

Arithmetic block 4, calculation step 3 (Calc 4): 

Arithmetic block 5, calculation step 4 (Calc 5): 

PLC G11 threshold switch (s): 

PLCG12 value table 1 (WT1): 

Multifunction output block (MFA 9): 

The cycle duration and pulse duration are output depending on the input signal.

IMPORTANT Signal identification number = Signal ID.

The signal IDs are notated in hexadecimal form.

ARITHMETIC UNIT - COMPARATOR 2, CALCULATION STEP 1 (COMP 2), CONFIGURATION

Input Signal name Signal ID Comparison assignment
Compare_2_a AU_Const_3 0xF03A Input a (a) > Input b (b)
Compare_2_b VehSpd_Disp 0x3053  
Compare_2_c VehSpd_Disp 0x3053  
Compare_2_d Const_Bit_0 0x1000  
ARITHMETIC UNIT - CALCULATION BLOCK 3, CALCULATION STEP 2 (CALC 3), CONFIGURATION

Input Signal name Signal ID Upper limit value Lower limit value
Calc_3_a AU_Compare_2 0xF029 16, 376 0
Calc 3 m1 AU Const 4 0xF03B    
Calc_3_m2 Const_Bit_1 0x1001    
Calc_3_b Const_Bit_0 0x1000    
ARITHMETIC UNIT - CALCULATION BLOCK 4, CALCULATION STEP 3 (CALC 4), CONFIGURATION

Input Signal name Signal ID Upper limit value Lower limit value
Calc_4_a AU_Const_5 0xF03C 3, 600, 000 0
Calc_4_m1 Const_Bit_1 0x1001    
Calc_4_m2 AU_Calc_3 0xF002    
Calc_4_b Const_Bit_0 0x1000    
PLC G11 THRESHOLD SWITCH (S), CONFIGURATION

Input F1 F2 F3 F4 F5 F6 F7 F8 F9 F1 0 F1 1 F1 2 F1 3 F1 4 F1 5 F1 6 Signal name Signal ID Mode Sequential point (1)
SS1_1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 AU_Calc_4 0xF003 Threshold A 0
                                      Threshold B 800
                                      Threshold C 22 727
                                      Threshold D 65 535
ARITHMETIC UNIT - ARITHMETIC BLOCK 5, CALCULATION STEP 4 (CALC 5), CONFIGURATION

Input Signal name Signal ID Upper limit value Lower limit value
Calc_5_a AU_Calc_4 0xF003 400 0
Calc_5_m1 Const_Bit_1 0x1001    
Calc_5_m2 AU_Const_6 0xF03D    
Calc_5_b Const_Bit_0 0x1000    
PLC G12 VALUE TABLE 1 (WT1) CONFIGURATION

Input F 1   F 3 F 4 F 5 F 6 F 7 F 8 F 9 F 10 F 11 F 12 F 13 F 14 F 15 F 16 Signal name Signal ID Value table 1 Default value (Signal name) Const_Bit_0 0x1000
WT1_1 (Value 1) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SPS_G11_SS1_A 0x91EA - Value 1 (Signal name) AU_Calc_5 0xF004
WT1_2 (Value 2) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SPS_G11_SS1_B 0x91EB - Value 2 (Signal name) SPS_G12_K1 0xB092
WT1_3 (Value 3) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SPS_G11_SS1_C 0x91EC - Value 3 (Signal name) Const_Bit_0 0x1000
WT1_4 (Value 4) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Const_Bit_0 0x1000 - Value 4 (Signal name) Const_Bit_0 0x1000
ARITHMETIC UNIT - CONSTANT BLOCKS, CONFIGURATION

Constants block (KB_1) Arithmetic unit Meaning
Konstante 3 4, 094 Maximum reception value
Konstante 4 4 Number of pulses per meter
Konstante 5 3, 600, 000 Vehicle speed factor in cycle duration
Konstante 6 2 Pulse duration factor
PLC G12 VALUE TABLE 1 (WT1) CONFIGURATION

Konstantenblock 1 Constants block 1 (KB1) Group 12 Meaning
Konstante 1 400 Pulse duration
MULTIFUNCTION OUTPUT BLOCK (MFA9), CONFIGURATION

1 A high side, PWM F 1 F 2 F 3 F 4 F 5 F 6 F 7 F 8 F 9 F 1 0 F 1 1 F 1 2 F 1 3 F 1 4 F 1 5 F 1 6 Signal name Signal ID Multifunction output block -
Eingang1 Input1 (Active)  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 AU_Compare_2 0xF029 - Type  Output (1)
Eingang2 Input2 (Const/pulse)  - - - - - - - - - - - - - - - - Const_Bit_0 0x1000   Reactivation attempts  1
Eingang3 Input3 (Cutoff reset)  - - - - - - - - - - - - - - - - Term15_Actv 0x1106   PWM type  Time (1)
Eingang4 Input4 (Cycle time)  - - - - - - - - - - - - - - - - Const_Bit_0 0x1000 -
Eingang5 Input5 (Pulse time)  - - - - - - - - - - - - - - - - Const_Bit_1 0x1001  
Eingang6 Input6 (PWM active)  - - - - - - - - - - - - - - - - AU_Compare_2 0xF029  
Eingang7 Input7 (PWM period)  - - - - - - - - - - - - - - - - AU_Calc_4 0xF003  
Eingang8 Input8 (PWM duty)  - - - - - - - - - - - - - - - - SPS_G12_WT1 0xB09A