Arithmetic, PSM Function - GF54.21-D-3055TSB

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) 

Arithmetic unit brief description 

The arithmetic unit is a supplement to the programmable logic controller (PLC) in the parameterizable special module (PSM) control unit (N26/16). The user can carry out general arithmetic operations via the arithmetic unit.

The arithmetic unit comprises the following blocks: 40 arithmetic blocks, 16 filters, 16 differentiators/integrators, 16 comparators, 40 constants, 32 permanent memories (NV-RAM) and 8 characteristics. The parameterization of these blocks is comparable to the parameterization of PLC blocks.

Arithmetic unit with the following functions and with number: 

• Arithmetic block, 40

  For a configuration example, see "PSM arithmetic, example for PSM function - Outside temperature, calculation block".

• Filter block, 16

  For a configuration example, see "PSM arithmetic, example for PSM function - Display dimming, filter block".

• Differentiator/integrator, 16

  For a configuration example, see "PSM arithmetic, example for PSM function - Vehicle speed signal, differentiator/integrator".

• Compare block, 16

  For a configuration example, see "PSM arithmetic, example for PSM function - Circuit 58D, compare block".

• Characteristics block, 8

  For a configuration example, see "PSM arithmetic, example for PSM function - Engine speed, characteristics block".

• Function block for constants, 40

  For a configuration example, see "PSM arithmetic, example for PSM function - Interior temperature, constants".

• Function block for non-volatile data memory (Non Volatile Random Access Memory (NVRAM)), block 32

Arithmetic unit arithmetic steps 

The function blocks arithmetic block, filter block, differentiator/integrator, comparison block and characteristics block for the arithmetic unit can be individually assigned for processing purposes to one of 4 arithmetic operations.

The cycle time for four arithmetic steps totals 20 ms.

They are processed successively from arithmetic step 1 to 4. The results for each arithmetic step are available after they have been processed in the signal pool, and they can continue to be used in the following arithmetic steps.

The function blocks arithmetic block, filter block, differentiator/integrator, comparison block, characteristics block and NVRAM block are described in detail in the following documents:

• PSM arithmetic, calculation block function 
• PSM arithmetic, filter block function 
• PSM arithmetic, differentiator/integrator function 
• PSM arithmetic, comparison block function 
• PSM arithmetic, characteristic block function 
• PSM arithmetic, NVRAM block function 

	PSM arithmetic, example of PSM function	Outside temperature, arithmetic block	GF54.21-D-3055-01TSG
		Display dimming, filter block	GF54.21-D-3055-01TSH
		Speed signal, differentiate, integrate	GF54.21-D-3055-01TSI
		Circuit 58D, comparison block	GF54.21-D-3055-01TSJ
		Engine speed, characteristic block	GF54.21-D-3055-01TSK
		Interior temperature, constants	GF54.21-D-3055-01TSL
	Overview of system components for parameterizable special module (PSM)		GF54.21-D-9998TSB