PACSystems Support for Reflective Memory
About this task
PACSystems PLC support reflective memory cards, as follows.
- Write data from reflective memory.
- Read data from reflective memory.
Write Data from Reflective Memory
On PACSystems, there are four functions that allow an application running on a PAC System CPU to communicate with a reflective memory card:
-
BUS_WRT_DWORD
orBUS_WRT_WORD
to write data to the network.
-
BUS_RD_DWORD
orBUS_WRT_WORD
to read data from the network.
The following examples are for use with a PAC PLC application interfacing to a RFM interface (named a CMX
interface).
Note: Examples for the 9070 are not currently available.
Typical write VME
functions take the following parameters, related to the location of the CMX
module (defined in the Hardware Configuration portion of the PLC application) and the memory that is to be written:
Parameter | Description | |
(enable) | ||
data | IN | PLC Memory space that is to be written to the Memory Xchange module, *note this must match in byte size the number of items written. |
Rack | R | Rack where the Memory Xchange module is located. |
Slot | S | Slot where the Memory Xchange module is located. |
Subslot | SS | Set to 0, unused with memory Xchange modules. |
Region | RGN | Which of the 4 memory regions in the memory Xchange module. |
Offset | OFF | 0-based number indicating what portion of the memory region is to be accessed. |
DWord | Number of DWORDs to be written. | |
Output | ST | Status of the operation. |
Reference | In | Reference for the Data to be written. |
For detailed instructions, see PACSystems Memory Xchange Modules Users' Manual, GFK-2300.
In the following PAC Ladder example, the application will:
- Write every scan as a single DWord of data to an RFM interface card that is located at