ABB CI868K01-eA DCS programmable communication unit
These parameters affect the allocation of memory within the process sta tion. When there are an extremely large
number of objects in the FieldCon troller, errors may occur on loading the objects; these settings may be al tered to try to make the project loadable.
Under normal circumstances the boot parameters should not be
changed. If they are changed, then the resource is initialized when
the modified boot parameters are loaded.
Attention should also be paid to the system variables PRAM_Free
and RAM_Free after loading. If the variable PRAM_Free has a
value of 0, then the value of PRAM_Size must be increased; if the
variable RAM_Free is set to 0, then both PRAM_Size and the
maximum number of objects must be reduced.
The AC 800F has 4 Mbytes memory. The memory is subdivided into differ ent parts as listed below.
The following are filed in the Flash memory :
• Operating system
• Boot-EPROM
The RAM memory is divided into sections ::
• object directory
• PRAM
• redundancy memory
• object data
• communication management
The memory for the objects, memory for PRAM and, if available, memory
for redundancy can be adjusted in the boot parameters of the resource.
Any surplus memory is made available in RAM. There is no absolute limit
on the memory ranges that can be set. Whenever a limit is reached, it can
be changed. This results in a reduction of free RAM.
To ascertain a suitable value for PRAM, current values can be read in
commissioning mode. These values are shown in the following system variables:
PS.PRAM_SIZE The PRAM size set in the boot parameters
PS.PRAM_FREE The proportion of free PRAM
PS.RAM_SIZE The amount of RAM in use
PS.RAM_FREE The proportion of free RAM
Max. no.
of objects The maximum number of objects that can be loaded on the resource
Configuration
date (PRAM) Memory size in Kbytes that is reserved for the configuration data. This
memory area is cold-start resistant.
Configured
redundancy memory Memory size in Kbytes that is reserved for the transfer of redundancy data.
Max. redundancy
memory required Maximum size of memory required by the project for transfer of redundancy
data.
The redundancy memory is only shown in redundant and plausible
process stations.
Tasks Communication management parameters. Every communication link requires internal system resources such as additional memory or system objects.
Network buffer Area of memory in Kbytes that is reserved for the communication links.
Interface
objects Maximum number of objects that can be reserved for interfaces

Communication link Required no. of interface objects
Link module DCO01 1
Tele Control Library 4
Profibus Master 2
Profibus Slave 0
Modbus Master 2
Modbus Slave 2
Protronic / Freelance 100 1
Sartorius 1
Send 1
Receive 1
Interbus Send 1
Interbus Receive 1
I/O bus (CAN)
Enable This configures the usage of slot F1 in the FieldController. If a CAN module
is installed in that slot, then the CAN bus must be activated here. If any
other module is installed in slot F1, then the CAN bus must be deactivated.
Transmission
rate Select a transmission rate of 100 or 500 Kbit/s of the station bus (default
500 Kbit/s). The transmission rate is closely linked to the distance between
two stations of one process station.
Transmission rate Distance to last I/O unit
500 Kbit/s 80m
100 Kbit/s 400m
I/O Bus Select the I/O protocol
Redundancy Default, - I/O EPROM’s capable of redundant operation must be
plugged on all I/O modules.
Not redundant As of version 6.1 (AC 800F only) not supported.