Specifications

CC-Link Head Station STL-BT1 (CC-Link)
3 - 10
MITSUBISHI ELECTRIC
3.2.8 Local Process Image
After switching on, the head station STL-BT1 recognizes all connected STlite modules which supply
data or wait for data (data width/bit width > 0). Analog and digital I/O modules can be mixed.
The head station produces an internal process image from the data width and the type of STlite mod-
ule as well as the position of the STlite modules in the node. It is divided into an input and an output
data area.
The data of the digital STlite modules are bit orientated, i.e. the data exchange is made bit for bit. The
analog and special function STlite modules are all byte orientated modules, i.e. modules where the
data exchange is made byte for byte.
The data of the STlite I/O modules are separated for the local input and output process image in the
sequence of their position after the head station in the individual process image.
In the respective I/O area, first of all analog modules are mapped, then all digital modules, even if the
order of the connected analog and digital modules does not comply with this order. The bits of the
digital modules are grouped, each of these groups having a data width of 1 byte. Should the number
of digital I/Os exceed 8 bits, the head station automatically starts another byte.
Address Area per Station
The areas shown in the following table are allocated for the remote I/O (RX/RY: bit devices) and remote
registers (RWw/RWr: word devices) by the master station, depending on the number of occupied sta-
tions.

RX: Inputs from digital input modules

RY: Outputs to digital output modules

RWr: Input data from analog modules or special function modules (e. g. counter)

RWw: Output data to analog modules or special function modules
NOTE
For the number of input and output bits or bytes of the connected STlite modules please refer to
the corresponding I/O module description in the appendix of this manual.
NOTE A process image restructuring may result if a node is changed or extended. In this case the process
data addresses also change in comparison with earlier ones. In the event of adding a module, take
the process data of all previous modules into account.
NOTE Sixteen points of the remote I/O are reserved for the system.
Type of data
Number of occupied stations
1 2 3 4
Remote input: RX

Total 32 points 64 points 96 points 128 points
User area 16 points 48 points 80 points 112 points
Remote output: RY

Total 32 points 64 points 96 points 128 points
User area 16 points 48 points 80 points 112 points
Remote registers
RWr

4 points 8 points 12 points 16 points
RWw

4 points 8 points 12 points 16 points
Tab. 3-5: The size of the address area depends on the number of occupied stations