Direct Access Certain values are mapped directly into words. These words can be monitored continuously but they are not configurable. Application Layer Multiple Parameter Access (MPA) Notes: • MPA is used on Level products only. • In Siemens Milltronics’ products, the memory is arranged as Parameter number, Primary Index, Secondary Index. 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 number, 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, then go back 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.
Secondary Index The secondary index is nearly always left at zero. See the manual for the Siemens Milltronics SmartLinx instrument for information on parameters, including those which require a secondary index. 7ML19981BH02 SmartLinx DeviceNet – INSTRUCTION MANUAL Page 19