Maxiflex P3 PAC User Manual
32
-© Omniflex
UMM126XR18.pdf
given in the intelligent module User Manual to the DIT Start Address applicable to the I/O
Slot (from the table above).
Alternatively you can calculate the start address of an Intelligent I/O Module DIT as follows:
For Mode 1 (2000 DIT registers per I/O Slot) the calculation is:
Start Address = 30000 + (SlotNumber
– 1) x 2000
where SlotNumber can range from 1 to 15
For Mode 2 (4000 DIT registers per I/O Slot) the calculation is:
Start Address = 30000 + (SlotNumber
– 1) x 4000
where SlotNumber can range from 1 to 7
CAUTION: Attempts to read data from unallocated areas of the DIT space will give
indeterminate results.
CAUTION: The access times from these areas of the DIT are slower than from the CPU
Dynamic Data Area (DIT addresses 0
– 30,000). For fastest access from the SCADA/DCS of
data in the NIM’s, use the CPU User Program to copy the data from the NIM’s address space
into DIt registers in the address range 0-29,999
Example 1:
A P3 CPU is configured in Extended Addressing mode 1 (2000 DIT registers per I/O
Slot).
A M1580A Dual Serial NIM module is present in I/O Slot 2.
The first 2,000 registers o
f this module will be mapped into the CPU’s DIT address
space starting at DIT address 32,000.
To read the Alive Counter of the M1585B NIM module in slot 2, which is DIT register 23
in the DIT layout of the NIM module, read CPU DIT address 32,023.
The M1580A Serial NIM has a total of 4000 DIT registers. Only the first 2000 are
mapped into the CPU DI space. The balance of the M1580A’s DIT space can be
accessed through any of the communication ports of the P3 CPU by addressing this I/O
module directly as an “Intelligent Module in Slot”. See the M1580A User Manual for
information on this method of addressing.
6.5 CPU Configuration (Static) Data Space (60,000-65,499)
This DIT area is used to store configuration data for the functions supported in the P3 CPU,
such as Serial Port set up etc., and any I/O modules that require configuration (e.g. the
M1432 8 way thermocouple module).
Intelligent Modules with their own DIT’s, such as the M1585B Modbus Network Interface
Module described in 6.4 above are NOT configured in this space. These intelligent modules
store their own configuration.
This CPU Configuration/Static Data Space is stored in non-volatile memory in the CPU, (and
does not utilise the internal battery). This means that this data will still be valid even when the
on-board battery is LOW or is being changed.
In addition to the allocated configuration data in this Static Data space, there is an area
available for the user to store application specific configuration that will remain fixed for the
life of the application.