Multiple Parameter Access (MPA) Note: • MPA is used on Level products only. • In Siemens Milltronics’ products, the memory is arranged as Parameter number, Primary Index, Secondary Index. Application Layer This is a hand-shaking method where the user specifies the parameter number, secondary index, decimal place, and format, then the SmartLinx writes into a certain area all 10 primary indexes of that parameter. Using Multiple Parameter Access (MPA) 1. In the output table of the PLC (Write Block) write the values for the parameter num- ber, secondary Index, decimal place and format in the correct location. 2.
Monitor the Input table of the PLC (Read Block), and watch for the values you wrote to appear in the appropriate locations of the Read block, then go to Step 3. 3. Read the requested values in the appropriate location of the Read Block. These values are continuously updated. Continue reading from these words until values for another parameter are required. At that time, go to step 1. Note: MPA values are only updated in Run mode (word 12 = 0). Parameter Indexing with MPA Primary Index The primary index is implicit in the memory address. MPA values are returned through words 21 to 30 of the Read block (see page 27). Secondary Index The secondary index is nearly always left at zero.
See the Siemens Milltronics SmartLinx- compatible instrument manual for information on parameters, including those which require a secondary index. 7ML19981AQ03 SmartLinx PROFIBUS DP – INSTRUCTION MANUAL Page 21