S7 system function

System Function Blocks

Number	Name	Family	Description
SFB 0	CTU	IEC_TC	Count Up
SFB 1	CTD	IEC_TC	Count Down
SFB 2	CTUD	IEC_TC	Count Up/Down
SFB 3	TP	IEC_TC	Generate a Pulse
SFB 4	TON	IEC_TC	Generate an On Delay
SFB 5	TOF	IEC_TC	Generate an Off Delay
SFB 8	USEND	COM_FUNC	Uncoordinated Sending of Data
SFB 9	URCV	COM_FUNC	Uncoordinated Receiving of Data
SFB 12	BSEND	COM_FUNC	Sending Segmented Data
SFB 13	BRCV	COM_FUNC	Receiving Segmented Data
SFB 14	GET	COM_FUNC	Read Data from a Remote CPU
SFB 15	PUT	COM_FUNC	Write Data to a Remote CPU
SFB 16	PRINT	COM_FUNC	Send Data to Printer
SFB 19	START	COM_FUNC	Initiate a Warm or Cold Restart on a Remote Device
SFB 20	STOP	COM_FUNC	Changing a Remote Device to the STOP State
SFB 21	RESUME	COM_FUNC	Initiate a Hot Restart on a Remote Device
SFB 22	STATUS	COM_FUNC	Query the Status of a Remote Partner
SFB 23	USTATUS	COM_FUNC	Receive the Status of a Remote Device
SFB 29	HS_COUNT	COUNTERS	Counter (high-speed counter, integrated function) (only exist on the CPU 312 IFM and CPU 314 IFM)
SFB 30	FREQ_MES	COUNTERS	Frequency Meter (frequency meter, integrated function (only exist on the CPU 312 IFM and CPU 314 IFM)
SFB 31	NOTIFY_8P	COM_FUNC	Generating block related messages without acknowledgement indication
SFB 32	DRUM	TIMERS	Implement a Sequencer
SFB 33	ALARM	COM_FUNC	Generate Block-Related Messages with Acknowledgment Display
SFB 34	ALARM_8	COM_FUNC	Generate Block-Related Messages without Values for 8 Signals
SFB 35	ALARM_8P	COM_FUNC	Generate Block-Related Messages with Values for 8 Signals
SFB 36	NOTIFY	COM_FUNC	Generate Block-Related Messages without Acknowledgment Display
SFB 37	AR_SEND	COM_FUNC	Send Archive Data
SFB 38	HSC_A_B	COUNTERS	Counter A/B (integrated function) (only exist on the CPU 314 IFM)
SFB 39	POS	ICONT	Position (integrated function) (only exist on the CPU 314 IFM)
SFB 41	CONT_C	ICONT	Continuous Control (only exist on the CPU 314 IFM)
SFB 42	CONT_S	ICONT	Step Control (only exist on the CPU 314 IFM)
SFB 43	PULSEGEN	ICONT	Pulse Generation (only exist on the CPU 314 IFM)
SFB 44	ANALOG	TEC_FUNC	Positioning with Analog Output (only exist on the S7-300C CPUs)
SFB 46	DIGITAL	TEC_FUNC	Positioning with Digital Output (only exist on the S7-300C CPUs)
SFB 47	COUNT	TEC_FUNC	Controlling the Counter (only exist on the S7-300C CPUs)
SFB 48	FREQUENC	TEC_FUNC	Controlling the Frequency Measurement (only exist on the S7-300C CPUs)
SFB 49	PULSE	TEC_FUNC	Controlling Pulse Width Modulation (only exist on the S7-300C CPUs)
SFB 52	RDREC	DP	Reading a Data Record
SFB 53	WRREC	DP	Writing a Data Record
SFB 54	RALRM	DP	Receiving an Interrupt
SFB 60	SEND_PTP	TEC_FUNC	Sending Data (ASCII, 3964(R)) (only exist on the S7-300C CPUs)
SFB 61	RECV_PTP	TEC_FUNC	Receiving Data (ASCII, 3964(R)) (only exist on the S7-300C CPUs)
SFB 62	RES_RECV	TEC_FUNC	Deleting the Receive Buffer (ASCII, 3964(R)) (only exist on the S7-300C CPUs)
SFB 63	SEND_RK	TEC_FUNC	Sending Data (RK 512) (only exist on the S7-300C CPUs)
SFB 64	FETCH_RK	TEC_FUNC	Fetching Data (RK 512) (only exist on the S7-300C CPUs)
SFB 65	SERVE_RK	TEC_FUNC	Receiving and Providing Data (RK 512) (only exist on the S7-300C CPUs)
SFB 75	SALRM	DP	Send interrupt to DP master
SFB 81	RD_DPAR	IO_FUNCT	Read Predefined Parameter

System Function Calls

Number	Name	Family	Description
SFC 0	SET_CLK	CLK_FUNC	Set System Clock
SFC 1	READ_CLK	CLK_FUNC	Read System Clock
SFC 2	SET_RTM	CLK_FUNC	Set Run-time Meter
SFC 3	CTRL_RTM	CLK_FUNC	Start/Stop Run-time Meter
SFC 4	READ_RTM	CLK_FUNC	Read Run-time Meter
SFC 5	GADR_LGC	IO_FUNCT	Query Logical Address of a Channel
SFC 6	RD_SINFO	DB_FUNCT	Read OB Start Information
SFC 7	DP_PRAL	DP	Trigger a Hardware Interrupt on the DP Master
SFC 9	EN_MSG	COM_FUNC	Enable Block-Related, Symbol-Related and Group Status Messages
SFC 10	DIS_MSG	COM_FUNC	Disable Block-Related, Symbol-Related and Group Status Messages
SFC 11	DPSYC_FR	DP	Synchronize Groups of DP Slaves
SFC 12	D_ACT_DP	DP	Deactivation and activation of DP slaves
SFC 13	DPNRM_DG	DIAGNSTC	Read Diagnostic Data of a DP Slave (Slave Diagnostics)
SFC 14	DPRD_DAT	DP	Read Consistent Data of a Standard DP Slave
SFC 15	DPWR_DAT	DP	Write Consistent Data to a DP Standard Slave
SFC 17	ALARM_SQ	PMC_FUNC	Generate Acknowledgeable Block-Related Messages
SFC 18	ALARM_S	PMC_FUNC	Generate Permanently Acknowledged Block-Related Messages
SFC 19	ALARM_SC	PMC_FUNC	Query the Acknowledgment Status of the last ALARM_SQ Entering State Message
SFC 20	BLKMOV	MOVE	Copy Variables
SFC 21	FILL	MOVE	Initialize a Memory Area
SFC 22	CREAT_DB	DB_FUNCT	Create Data Block
SFC 23	DEL_DB	DB_FUNCT	Delete Data Block
SFC 24	TEST_DB	DB_FUNCT	Test Data Block
SFC 25	COMPRESS	DB_FUNCT	Compress the User Memory
SFC 26	UPDAT_PI	IO_FUNCT	Update the Process Image Update Table
SFC 27	UPDAT_PO	IO_FUNCT	Update the Process Image Output Table
SFC 28	SET_TINT	PGM_CNTL	Set Time-of-Day Interrupt
SFC 29	CAN_TINT	PGM_CNTL	Cancel Time-of-Day Interrupt
SFC 30	ACT_TINT	PGM_CNTL	Activate Time-of-Day Interrupt
SFC 31	QRY_TINT	PGM_CNTL	Query Time-of-Day Interrupt
SFC 32	SRT_DINT	PGM_CNTL	Start Time-Delay Interrupt
SFC 33	CAN_DINT	PGM_CNTL	Cancel Time-Delay Interrupt
SFC 34	QRY_DINT	PGM_CNTL	Query Time-Delay Interrupt
SFC 35	MP_ALM	PGM_CNTL	Trigger Multicomputing Interrupt
SFC 36	MSK_FLT	DIAGNSTC	Mask Synchronous Errors
SFC 37	DMSK_FLT	DIAGNSTC	Unmask Synchronous Errors
SFC 38	READ_ERR	DIAGNSTC	Read Error Register
SFC 39	DIS_IRT	IRT_FUNC	Disable New Interrupts and Asynchronous Errors
SFC 40	EN_IRT	IRT_FUNC	Enable New Interrupts and Asynchronous Errors
SFC 41	DIS_AIRT	IRT_FUNC	Delay Higher Priority Interrupts and Asynchronous Errors
SFC 42	EN_AIRT	IRT_FUNC	Enable Higher Priority Interrupts and Asynchronous Errors
SFC 43	RE_TRIGR	PGM_CNTL	Re-trigger Cycle Time Monitoring
SFC 44	REPL_VAL	DIAGNSTC	Transfer Substitute Value to Accumulator 1
SFC 46	STP	PGM_CNTL	Change the CPU to STOP
SFC 47	WAIT	PGM_CNTL	Delay Execution of the User Program
SFC 48	SNC_RTCB	CLK_FUNC	Synchronize Slave Clocks
SFC 49	LGC_GADR	IO_FUNCT	Query the Module Slot Belonging to a Logical Address
SFC 50	RD_LGADR	IO_FUNCT	Query all Logical Addresses of a Module
SFC 51	RDSYSST	DIAGNSTC	Read a System Status List or Partial List
SFC 52	WR_USMSG	DIAGNSTC	Write a User-Defined Diagnostic Event to the Diagnostic Buffer
SFC 54	RD_PARM	IO_FUNCT	Read Defined Parameters
SFC 55	WR_PARM	IO_FUNCT	Write Dynamic Parameters
SFC 56	WR_DPARM	IO_FUNCT	Write Default Parameters
SFC 57	PARM_MOD	IO_FUNCT	Assign Parameters to a Module
SFC 58	WR_REC	IO_FUNCT	Write a Data Record
SFC 59	RD_REC	IO_FUNCT	Read a Data Record
SFC 60	GD_SND	COM_FUNC	Send a GD Packet
SFC 61	GD_RCV	COM_FUNC	Fetch a Received GD Packet
SFC 62	CONTROL	COM_FUNC	Query the Status of a Connection Belonging to a Communication SFB Instance
SFC 63	AB_CALL	PLASTICS	Assembly Code Block (only exists for CPU 614)
SFC 64	TIME_TCK	CLK_FUNC	Read the System Time
SFC 65	X_SEND	COM_FUNC	Send Data to a Communication Partner outside the Local S7 Station
SFC 66	X_RCV	COM_FUNC	Receive Data from a Communication Partner outside the Local S7 Station
SFC 67	X_GET	COM_FUNC	Read Data from a Communication Partner outside the Local S7 Station
SFC 68	X_PUT	COM_FUNC	Write Data to a Communication Partner outside the Local S7 Station
SFC 69	X_ABORT	COM_FUNC	Abort an Existing Connection to a Communication Partner outside the Local S7 Station
SFC 70	GEO_LOG	IO_FUNCT	Determine Start Address of a Module
SFC 71	LOG_GEO	IO_FUNCT	Determine the Slot Belonging to a Logical Address
SFC 72	I_GET	COM_FUNC	Read Data from a Communication Partner within the Local S7 Station
SFC 73	I_PUT	COM_FUNC	Write Data to a Communication Partner within the Local S7 Station
SFC 74	I_ABORT	COM_FUNC	Abort an Existing Connection to a Communication Partner within the Local S7 Station
SFC 78	OB_RT	DIAGNSTC	Determine OB program runtime
SFC 79	SET	BIT_LOGC	Set a Range of Outputs
SFC 80	RSET	BIT_LOGC	Reset a Range of Outputs
SFC 81	UBLKMOV	MOVE	Uninterruptible Block Move
SFC 82	CREA_DBL	DB_CTRL	Create a Data Block in the Load Memory
SFC 83	READ_DBL	DB_CTRL	Read from a Data Block in Load Memory
SFC 84	WRIT_DBL	DB_CTRL	Write from a Data Block in Load Memory
SFC 85	CREA_DB	DB_FUNCT	Create a Data Block
SFC 87	C_DIAG	COM_FUNC	Diagnosis of the Actual Connection Status
SFC 90	H_CTRL	HF_FUNCT	Control Operation in H Systems
SFC 100	SET_CLKS	CLK_FUNC	Setting the Time-of-Day and the TOD Status
SFC 101	RTM	CLK_FUNC	Handling runtime meters
SFC 102	RD_DPARA	IO_FUNCT	Redefined Parameters
SFC 103	DP_TOPOL	DP	Identifying the bus topology in a DP master system
SFC 104	CIR	PGM_CNTL	Controlling CiR
SFC 105	READ_SI	PMC_FUNC	Reading Dynamic System Resources
SFC 106	DEL_SI	PMC_FUNC	Deleting Dynamic System Resources
SFC 107	ALARM_DQ	PMC_FUNC	Generating Always Acknowledgeable and Block-Related Messages
SFC 108	ALARM_D	PMC_FUNC	Generating Always Acknowledgeable and Block-Related Messages
SFC 112	PN_IN	PROFIne2	Update inputs in the user program interface of PROFInet components
SFC 113	PN_OUT	PROFIne2	Update outputs in the user program interface of PROFInet components
SFC 114	PN_DP	PROFIne2	Update DP interconnections
SFC 126	SYNC_PI	IO_FUNCT	Update process image partition input table in synchronous cycle
SFC 127	SYNC_PO	IO_FUNCT	Update process image partition output table in synchronou

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