Identification and Maintenance functions (I&M) allow access to blocks of data kept inside each PROFINET device by use of acyclic read/write record requests. Information such as device name, location in the factory, maintenance information for this device, etc. can be stored in each device. These records are written with a programming tool, an engineering tool, or via read/write record requests under the application program control. The table below summarizes the different types of I&M records. User writable I&M records (I&M1-3) are persistent and will remain until they are changed or until the device is reset to factory settings (cleared).
I&M0 – Manufacturer Data
I&M0 read-only data records are permanently stored inside the device by the device vendor. This data is related to the device application layer. The following table shows the content description of I&M0.
I&M1 – I&M3 – User Writeable Data Areas
I&M1 contains two fields: Tag-function and Tag-location. “Tag function” is a 32-byte visible string that indicates the submodule’s function or task. “Tag location” is a 22-byte visible string that indicates the submodule’s location.
I&M2 is a Date and time function in the YYYY-MM-DD HH:MM format. For example, 2018-08-10 10:50 denotes August 10, 2018 at 10:50 AM.
I&M3 is a general “Descriptor” function that is a 54-byte visible string for holding additional information. This information is available to save historical documentation specific to this device.
These I&M records may be written during the programming process to write the records into the device.
I&M4 – Reserved for PROFIsafe
You can find more information on I&M4 and its’ uses in the Functional Safety section of PROFINET University.
I&M5 – Optional Device Manufacturer Records
I&M5 is optional. When present, I&M5 data describes the communication manufacturer. It references the stack vendor or communication chip stack vendor. It might not be unusual for two PROFINET devices from different vendors to report the same third party vendor in their I&M5 data. I&M5 data is all about the interface vendor.
Besides I&M, Asset Management is an additional PROFINET feature for providing information such as firmware and hardware versions, from devices outside the PROFINET address space. Asset Management is based on I&M and works with standardized data sets.
Identification and Maintenance functions are implemented in every PROFINET device. This information can be particularly useful since it is accessible across the network. From the control room or the maintenance room, I&M information is available to help maintain your installation. If you are developing a PROFINET device and would like to know more about implementing PROFINET I&M functions, you can find more information in the PROFINET Services Specification which available as part of the PROFINET Test Bundle
This article originally appeared as a lesson at PROFINET University