PSM Arithmetic, Example Of PSM Function - GF54.21-S-3055-01TRF

Model 447 

With Code ED5 (Parameterisable special module) 

Except Code XM7 (MOPF II) 

Vehicle interior temperature, constants 

Model 448 

With Code ED5 (Parameterisable special module) 

Except Code XM7 (MOPF II) 

Vehicle interior temperature, constants 

Courtesy of MERCEDES-BENZ USA

Vehicle interior temperature function blocks 

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

Formula: duty cycle = (vehicle interior temperature [°C] * 4)/232 [°C]

Value range of vehicle interior temperature	0...58°C
Value range of pulse width modulated signal	0...100 %
Frequency	200 Hz

100 If no air conditioning system is installed ("AAC_VH = [0]"), then the output is constantly switched through (i.e. pulse width modulation (PWM) = 100%).

The vehicle interior temperature is realized through the programmable logic controller (PLC) group, arithmetic unit (AU) and the "MFA" blocks. The picture shows the simplified function block operation. The configuration is available in the tables.

Function description of implementation 

PLC G9 value table 1 (WT1 PLC G9): 

• Forward vehicle interior temperature if air conditioning system is installed, otherwise default value is output.

Comparator 6, calculation step 1 (Comp 6): 

• Check whether vehicle interior temperature is within valid value range, if so, output 1.

Comparator 7, calculation step 2 (Comp 7): 

• Check whether vehicle interior temperature is limited to valid value range.

Arithmetic unit memory (Memory 1): 

• Output valid signal, otherwise output last stored value.

PLC G12 flip-flop 2 (FF2): 

• Output 1 if a valid signal is received after wake-up.

PLC G8 value table 1 (WT 1 PLC G8): 

• If valid signal was received, result is output from memory, otherwise default value.

Calculation block 10, calculation step 4 (Calc 10): 

• Conversion of the valid signal 0 to 232 to 232 into the duty cycle 0 to 10 000 to 10000 (0 to 100 to 100%).

-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Signal name	Signal ID
Input	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15	F16	Signal name	Identification number (ID) of signal	Default value (signal name)	Out_AU_Const_14	0x8040
WT1_1 (value 1)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	HVAC_AVL	0x1290	Value 1 (signal name)	AirTemp_Insd	0x237
WT1_2 (value 2)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Const_Bit_0	0x1000	Value 2 (signal name)	Const_Bit_0	0x1000
WT1_3 (value 3)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Const_Bit_0	0x1000	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

Input	Signal name	Signal ID	Compare operation
Compare_6_a	Out_AU_Const_14	0x804D	Input a (a) ≥ Input b (b)
Compare_6_b	Out_G9_WT1	0x3070
Compare_6_c	Const_Bit_1	0x1001
Compare_6_d	Const_Bit_0	0x1000

Input	Signal name	Signal ID	Terminal 58D, comparator block
Compare_7_a	Out_AU_Const_14	0x804D	Input a (a) ≥ Input b (b)
Compare_7_b	Out_G9_WT1	0x3070
Compare_7_c	Out_G9_WT1	0x3070
Compare_7_d	Const_Bit_0	0x1000

Input	Signal name	Signal ID	Arithmetic unit memory	-	-
Memory_1_value	Out_AU_Compare_7	0x802A	-	Activation delay (in 20 ms steps)	0
Memory_1_Enable	Out_AU_Compare_6	0x8029		-	-

Input	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15	F16	Signal name	Signal ID	Mode	Sequential point (1)
FF2_1 (set/data)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Out_AU_Calc_4	0x8003	Threshold A	0
FF2_2 (reset/clock)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	-	-	Threshold B	800

-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	PLC G8 value table 1 configuration	-	Signal name	Signal ID
Input	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15	F16	Signal name	Signal ID		Default value (signal name)	Out_AU_Const_14	0x8040
WT1_1 (value 1)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Out_G12_FF2	0x3089		Value 1 (signal name)	AirTemp_Insd	0x237
WT1_2 (value 2)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Const_Bit_0	0x1000		Value 2 (signal name)	Const_Bit_0	0x1000
WT1_3 (value 3)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Const_Bit_0	0x1000		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

Input	Signal name	Signal ID	Upper limit value	Lower limit value
Calc_10_a	Out_G8_WT1	0x3067	1000	0
Calc_10_m1	Out_AU_Const_12	0x804B
Calc_10_m2	Out_AU_Const_14	0x804D
Calc_10_b	Const_Bit_0	0x1000

Constants	Arithmetic unit	Meaning
Constant 12	10000 000	Maximum duty cycle
Constant 13	2000	Frequency
Constant 14	250	Maximum valid value of interior CAN (CAN B) signal

1A High-Side, PWM	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15	F16	Signal name	Signal ID	MFA 6	-
MFA6_Eingang1 (active)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Const_Bit_1	0x1001	-	Model	Output (1)
MFA6_Eingang2 (const/pulse)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_0	0x1000		Reactivation attempts	1
MFA6_Eingang3 (Cutoff reset)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Term15_Actv	0x1219		PWM type	Frequency (0)
MFA6_Eingang4 (cycle time)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_0	0x1000	-
MFA6_Eingang5 (pulse time)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_0	0x1000
MFA6_Eingang6 (PWM active)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_1	0x1001
MFA6_Eingang7 (PWM cycle)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Out_AU_Const_13	0x804C
MFA6_Eingang8 (PWM duty)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Out_AU_Calc_10	0x8009