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S7-400 CPU 41x -- Configuring and programming communication -- Using communication blocks
When using the FB81 S_MODB on an S7-400 with more than 8 Kbytes of marker, how do you access the marker area above MB 255?
How do you enable the ad-hoc mode when you call the TRCV instruction?
How do you use the blocks for MODBUS/TCP communication over the integrated PROFINET interface of the S7-300 and S7-400 CPUs and IM151-8 PN/DP CPU in STEP 7 Professional (TIA Portal)?
How do you establish a redundant MODBUS/TCP communication over the integrated PROFINET interface of a CPU 41x-H in STEP 7 V5.5?
What is the difference between the initialization and runtime parameters on the blocks for Modbus TCP?
Why is the status value A090 (hex) output for Modbus TCP although you have entered the correct license?
What are the differences between the licensed version and the downloadable demo version of the blocks for Modbus TCP?
Why is the value A083 (hex) output permanently at the STATUS output parameter of the block for Modbus TCP when the ENQ_ENR=true input parameter has been set?
Which blocks for Modbus TCP can you rename or re-wire when the block numbers of the Modbus blocks are already being used in the user program?
How can you read out diagnostics data from a SIRIUS 3RK3 modular safety system using a S7-300/400 CPU?
Which communication options are there in SIMATIC S7?
How does data communication work between S7-300/S7- 400 and S7-200 via MPI using S7 basic communication?
Consistent data in S7-400, summary of mechanisms
Which ports are released for Modbus/TCP communication and how many Modbus clients can communicate with a SIMATIC S7 CPU as Modbus server?
How do you implement chronological messaging with S7-400 CPUs and WinCC?
How do you configure a specified and an unspecified S7 connection for data exchange between S7-300 and/or S7-400 by way of Industrial Ethernet CPs?
How do you establish OPEN MODBUS / TCP communication from a SIMATIC S7 and where can you find further information?
How do you use WinCC flexible to transfer a project to an operator panel via S7 routing?
What restrictions are there for active jobs when communicating with SFC 58 / SFC 59 and SFB 52 / SFB 53 via PROFIBUS DP and PROFINET IO?
How do you program the communication blocks FB63 "TSEND", FB64 "TRECV", FB65 "TCON" and FB66 "TDISCON" in order to use the ISO-on-TCP protocol for data exchange by way of the integrated PROFINET interface of a CPU or by way of the CP443-1 Advanced?
How do you program the communication blocks FB63 "TSEND", FB64 "TRCV", FB65 "TCON" and FB66 "TDISCON" in order to use the TCP protocol for data exchange by means of the integrated PROFINET interface of an S7-300 or S7-400 CPU?
How do you program the communication blocks FB67 "TUSEND", FB68 "TURCV", FB65 "TCON" and FB66 "TDISCON" in order to use the UDP protocol for data exchange by means of the integrated PROFINET interface of a CPU?
How can you access consistent data without SFC14/15 as part of the process image?
How great is data consistency in the PUT and GET S7 communication functions for the individual S7-400 CPUs?
S7-300 CPU 31x -- Configuring and programming communication -- Using communication blocks
How do you cyclically read out the 8 channels of the FM 350-2 counter module as quickly as possible?
How do you read out the IP address of the S7-300 CPU in the user program at runtime?
How do you enable the ad-hoc mode when you call the TRCV instruction?
How do you use the blocks for MODBUS/TCP communication over the integrated PROFINET interface of the S7-300 and S7-400 CPUs and IM151-8 PN/DP CPU in STEP 7 Professional (TIA Portal)?
Which security modules can be reached with SOFTNET Security Client V4 over a secure IPsec tunnel connection?
What is the difference between the initialization and runtime parameters on the blocks for Modbus TCP?
Why is the status value A090 (hex) output for Modbus TCP although you have entered the correct license?
What are the differences between the licensed version and the downloadable demo version of the blocks for Modbus TCP?
Why is the value A083 (hex) output permanently at the STATUS output parameter of the block for Modbus TCP when the ENQ_ENR=true input parameter has been set?
Which blocks for Modbus TCP can you rename or re-wire when the block numbers of the Modbus blocks are already being used in the user program?
How do you implement chronological messaging with S7-300 CPUs and WinCC?
How do you program communication blocks FB14 "GET" and FB15 "PUT" for data exchange in the S7 program of an S7-300 CPU?
How can you read out diagnostics data from a SIRIUS 3RK3 modular safety system using a S7-300/400 CPU?
Which ports are released for Modbus/TCP communication and how many Modbus clients can communicate with a SIMATIC S7 CPU as Modbus server?
How do you configure a specified and an unspecified S7 connection for data exchange between S7-300 and/or S7-400 by way of Industrial Ethernet CPs?
What restrictions are there for active jobs when communicating with SFC 58 / SFC 59 and SFB 52 / SFB 53 via PROFIBUS DP and PROFINET IO?
How do you program communication blocks FB12 "BSEND" and FB13 "BRCV" for data exchange in the S7 program of an S7-300 CPU?
How do you program the communication blocks FB63 "TSEND", FB64 "TRECV", FB65 "TCON" and FB66 "TDISCON" in order to use the ISO-on-TCP protocol for data exchange by way of the integrated PROFINET interface of a CPU or by way of the CP443-1 Advanced?
How do you program the communication blocks FB63 "TSEND", FB64 "TRCV", FB65 "TCON" and FB66 "TDISCON" in order to use the TCP protocol for data exchange by means of the integrated PROFINET interface of an S7-300 or S7-400 CPU?
How do you establish OPEN MODBUS / TCP communication from a SIMATIC S7 and where can you find further information?
How do you program the communication blocks FB67 "TUSEND", FB68 "TURCV", FB65 "TCON" and FB66 "TDISCON" in order to use the UDP protocol for data exchange by means of the integrated PROFINET interface of a CPU?
How does data communication work between S7-300/S7- 400 and S7-200 via MPI using S7 basic communication?
How great is data consistency in the PUT and GET S7 communication functions for the individual S7-300 CPUs and C7 complete devices?
How can you access via PROFIBUS DP another CPU, which is connected to the PROFIBUS DP as a slave, from a DP master using basic communication with SFC72 "I_GET" and SFC73 "I_PUT"?
How can you access consistent data without SFC14/15 as part of the process image?
PROFIBUS general -- Configuring and programming communication -- Using communication blocks
Transfer of analog values from and to the PROFIBUS DP slave
Which entries deal with consistent data in conjunction with distributed I/O?
How can you access consistent data without SFC14/15 as part of the process image?
Why does my new CPU 315-2DP (Order No: 6ES7 315-2AG10-0AB0) not process the SFC13 correctly?
How do you receive an alarm with the SFB 54 "RALRM" in compliance with DPV1?
DP slave lifelist using SFC51 "RDSYSST" instead of SFC12 "D_ACT_DP"
Can you use the "Signal System Error" function, the FB126 function block and the SFC13 "DPNRM_DG" system function simultaneously?
Notes for the use of the system function SFC12 "D_ACT_DP"
What is consistent data?
How do you read data consistently from a DP standard slave/PROFINET IO device and write it consistently to a DP standard slave/PROFINET IO device?
Disabling DP slaves after startup of the CPU
Diagnostics information of the FB125 with disabled DP slave
Enabling a disabled DP slave with SFC 12 "D_ACT_DP"
Parameter assignment of SFC 103 / SFC 59 required for identifying and reading out topology data
What are the requirements for using the "Prepare Line Diagnostics" function?
How can you access consistent data without SFC14/15 as part of the process image?
Part number:

Description:
Consistent data access > 4 bytes is now possible without the system functions SFC14/15. This option of being able to consistently access data > 4 bytes using download/transfer commands provides a particularly convenient and high-performance method of access (low runtime load).
The data area of a DP slave or IO device that is to be transferred consistently is transferred to a process image or process image partition. The data in this area is then always consistent. Afterwards you can use download/transfer commands (e.g. L IW 1) to access the process image or process image partition. There is no limitation of the area with respect to addressing.

  • The operating system automatically controls updating of the process image.
  • Updating of the process image partition is done either on the user side using SFCs or automatically on the system side through a link to an OB.
  • When you make a direct access (e.g. L PEW or T PAW) then there is no I/O access error.

Note:
Refer to the technical data to see whether your CPU supports process image partitions.

Overview:
You can use the following CPUs for configuring without "SFC14/15":
 

MLFB

S7 CPU 

Minimum firmware version

6ES7 31..

CPU 31x

2.5

6ES7 41.. CPU 41x 3.0
6ES7671-0RC03-0YA0 WinAC1 V4.0
1Only possible when using Hardnet CPs (CP 5613 / CP 5603 / CP 5623) and not Softnet CPs (CP 5611 / CP 5621).

Limits:
Transfer of consistent user data to a DP slave:

Upper limits for the transfer of consistent data to a DP slave are defined by the PROFIBUS DP standard. This is why only a maximum of 64 words = 128 bytes of user data can be transferred consistently in one block to a DP standard slave.

When configuring, you define the size of the consistent area. For this, in the special identification format (SKF) you can set a maximum length of 64 words = 128 bytes for the consistent data (128 bytes for inputs and 128 bytes for outputs); anything beyond that is not possible.

This upper limit applies only for pure user data. Diagnostics and parameter data is grouped into whole data records and is therefore always transferred consistently.

For this, in the general identification format (AKF) you can set a maximum length of 16 words = 32 bytes for the consistent data (32 bytes for inputs and 32 bytes for outputs); anything beyond that is not possible.

Please also note here that a CPU 41x as DP slave must be able to be configured on a third-party master (connection via GSD) via the general identification format (AKF). For this reason the transfer memory per virtual slot of a CPU 41x as DP slave to the PROFIBUS DP has a maximum size of 16 words = 32 bytes. You can configure up to 32 such virtual slots in the i-slave. The highest slot number is 35.

Transfer of consistent user data to an IO device:
The upper limit for the transfer of consistent data to an IO device is 255 bytes (254 bytes user data + 1 byte associated value). Even if more than 255 bytes can be transferred to an IO device, the upper limit is 255 bytes of consistent user data.

Important:
Do not use the system functions and the process image simultaneously. The consistency between process image values and the values of system function SFC14 is not guaranteed, because the process image is not tracked when reading with system function SFC14. In principle the process image is tracked when writing with system function SFC15, but not when reading. This means that the consistency between process image values and the values of system function SFC14 is not guaranteed.

Example:
The following example (for the process image partition 3 "TPA 3" of an S7-400 CPU) shows one possible configuration in the HW Config:

Requirements: The image process partition has already been updated via the SFC 26/27 or the process image updating has been linked to an OB.

  • TPA 3 under Output: These 50 bytes are consistent in the process image partition 3 and can thus be read with normal "load input xy" commands.
  • "---" under Input means: no storage in a process image. Only handling with system functions SFC14/15 is possible.

Keywords:
Hardware configuration, Consistency, Updating

 Entry ID:8751062   Date:2011-03-22 
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