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

Model 447 

With Code ED5 (Parameterisable special module) 

Except Code XM7 (MOPF II) 

Outside temperature, calculation block 

Model 448 

With Code ED5 (Parameterisable special module) 

Except Code XM7 (MOPF II) 

Outside temperature, calculation block 

Courtesy of MERCEDES-BENZ USA

Function blocks for outside temperature 

The outside temperature (interior CAN (CAN B): "AirTemp_OutSd") can be output on one of the pulse-width-modulation-compatible outputs (A).

Formula: duty cycle = (outside temperature [°C] + 40 [°C])/125 [°C]

Outside temperature value range	-40 to 85°C
Value range of pulse width modulated signal	0...100%
Frequency	200 Hz

If a value (W) outside the valid range is sent, the last valid value (W) is used. If a valid value (W) is still not available, 0 % pulse width modulation (PWM) is output. The PWM function for the outside temperature is implemented using groups of the programmable logic controller (PLC), arithmetic unit and multifunction output blocks. The picture above shows the simplified linking of the function blocks. The configuration is available in the tables.

Function description of implementation 

Comparator 6, calculation step 1 (Comp 6): 

• Check that the input signal is in the valid value range (0 to 250), then output "1", otherwise "0"

Comparator 7, calculation step 2 (Comp 7): 

• Restrict the valid value range of the input signal to 0 to 250; 250 is output for values (W) over 250.

Arithmetic unit memory (Memory 1): 

• Output the received signal if it is in the valid value range, otherwise output the value (W) stored last

Flip-flop 2 (FF2 PLC G12): 

• Output "1" if a valid signal was received after wake-up of a control unit

Value table 1 (WT1): 

• If a valid signal has been received, the result is output by the memory, otherwise the default value ("0")

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

• Conversion of the valid signal from 0 to 250 to the value range 0 to 10 000 to 10000 (0 to 100 to 100%)

Multifunction output block (MFA 6): 

• Output of PWM: Frequency comes from constant = 2000 (200 Hz); capacity utilization is result of calculation block 10, calculation step Rechenblock 104 (Calc 10), output (A) is permanently ON, i.e. PWM is output from locally active control unit.

Signal identification number = Signal ID.

The signal IDs are notated in hexadecimal form.

Input	Signal name	Signal ID	Compare operation
Compare_6_a	Out_AU_Const_14	0x804D	Input a (a) ≥ Input b (b)
Compare_6_b	AirTemp_OutSd	0x206E
Compare_6_c	Const_Bit_1	0x1001
Compare_6_d	Const_Bit_0	0x1000

Input	Signal name	Signal ID	Compare operation
Compare_7_a	Out_AU_Const_14	0x804D	Input a (a) ≥ Input b (b)
Compare_7_b	AirTemp_OutSd	0x206E
Compare_7_c	Const_Bit_1	0x1001
Compare_7_d	Const_Bit_0	0x1000

Input	Signal name	Signal ID	Activation delay (in 20 ms steps)
Memory_1_value	Out_AU_Compare_7	0x802A	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
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	Flip-flop type	D_FF (1)
FF2_2 (reset/clock)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	-	-	Flip-flop evaluation	Status-controlled/positive signal edge (0)

Input	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15	F16	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	Out_G12_FF2	0x3089		Value 1 (signal name)	Out_AU_Memory_1	0x8030
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	Lower limit value	Upper limit value
Calc_10_a	Out_G8_WT1	0x308B	0	10000
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	Maximum duty cycle
Constant 13	2000	Frequency
Constant 14	250	Maximum valid value (W)

1A High-Side, PWM	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15	F16	Signal name	Signal ID
Input 1 (active)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	Const_Bit_1	0x1001
Input 2 (const/pulse)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_0	0x1000
Input 3 (cycle time)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_0	0x1000
Input 4 (pulse time)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_0	0x1000
Input 5 (Cutoff reset)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Term15_Actv	0x1219
Input 6 (PWM active)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Const_Bit_1	0x1001
Input 7 (PWM freq./cycle)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Out_AU_Const_13	0x804C
Input 8 (PWM duty/pulse width)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	Out_AU_Calc_10	0x8009