All special function modules used as part of a PLC system contain data stored in buffer memory.
An example of this would be raw analogue input values from an analogue input module (special function module). Normally this information or data is transferred to PLC data registers and then any connected HMI accesses this information or data is from the PLC.
This technical tip explains how access to this buffer memory data directly from the special function module from a GOT HMI without the need for and PLC data registers being used.
To explain how to access Buffer memory data, 2 examples are shown below.
Example 1 (Qn PLC System)
This example shows how to access Buffer memory 10 of a special function module who’s starting I/O (Head) address in the PLC rack is 00 Hex. To demonstrate how to do this place a numeric display object on screen and enter BM00-10 into the device field.
Example 2 (FX PLC)
This example shows how to access Buffer memory 14012 of a special function module which is the first connected module on the right hand side of the FX PLC, i.e., unit number zero.
For further information please see the GOT screen design manual.