Advantages of the P-NET Protocol 　　　　--------------------------------------------------------------------------------　　　　All nodes that conform to the P-NET standard can be directly co ected to the bus and will immediately communicate together, because P-NET uses only one data rate, and only one choice is given for each of the communication layers.　　　　This differs from other standards, which allow many variatio  on each layer, resulting in many variants that are not able to communicate together.　　　　Any P-NET module, including a master, can be powered down or co ected to or disco ected from the bus, without interfering with the rest of the bus system.　　　　Co equently, modules can be exchanged during system operation, and a system can be expanded while the remaining production system continues to run.　　　　The need for configuration of communication parameters in P-NET is much reduced compared with other systems. In slave modules, the P-NET system integrator only has to set the node addre es, and in master modules, he only needs to define the node addre  and the number of masters.　　　　Therefore, training is reduced and allows any qualified technician to understand and i tall a P-NET system.　　　　The distributed proce ing power of a system can be increased, by simply co ecting additional masters.　　　　 ecial procedures have been included in the P-NET standard, making it po ible to change the addre  of a single node on the network, by mea  of its unique serial number. This allows individual P-NET node addre es to be changed while the system is still ru ing.　　Dip switches and other mechanical mechanisms can be avoided, and it is therefore po ible to build hermetically sealed P-NET nodes (e.g. IP-67).　　　　When designing a new device for use with P-NET, benefits will be seen from the fact that P-NET can be used to acce  any logical or physical addre  within the device, decided upon by the manufacturer. When a device is implemented with P-NET, both the test procedures performed during the development phase for the a lication program within the device, and the calibration and maintenance procedures used in the future, can be simplified. P-NET can therefore be used to look i ide the device in order to monitor program variables.　　　　The result of a measurement made by a slave, is presented to a master in a pre-proce ed form, in SI (metric) engineering units. The benefit is significant, since no repetitive scaling or conversion needs to be done by the master(s), leading to co iderable savings in proce ing power. For example, a temperature measurement will be converted to a floating point value by the slave ( IEEE 754 standard), and will be presented to all masters requesting the data in degrees centigrade.　　　　Identifiers used for acce ing the physical variable on the network, are ma ed via a ‘SOFTWIRE’ list. This list is generated while the a lication program is being compiled. Therefore, no real time tra lation is required, leading to very fast data acce .　　　　To e ure real time data collection, each frame tra mitted on the network is restricted to 56 data bytes. If the requested data length is higher than 56 bytes, it is automaticallydivided into several succe ive tra mi io .