ISPSoft User Manual

Chapter 6 Symbols
6.1.4 Assigning a Device to a Symbol and Setting the Initial
Value of a Symbol
A device is assigned to a symbol according to the data type of the symbol. Users can set the initial
value of a symbol. If a project is downloaded, the initial values of the symbols can be written into the
devices assigned to the symbols.
The principle of assigning devices to symbols is as follows. Different models have different
assignment principles.
Model
Assignment principle
• Users can assign devices to the global symbols and the local symbols declared in the
POUs of the program type. The system can also automatically assign devices to the
global symbols and the local symbols declared in the POUs of the program type.
• The system automatically assigns devices to the local symbols declared in the
function blocks. Users can not assign devices to the local symbols declared in the
AH500
function blocks by themselves.
• The devices assigned by the system are memories reserved by the CPU module, and
are not data registers or auxiliary relays. If the data type of a symbol is STEP, TIMER,
or COUNTER, the system will automatically assign a stepping relay, a timer, or a
counter to the symbol.
• Users can assign devices to all the global symbols and the local symbols. The system
can also automatically assign devices to all the global symbols and the local symbols.
DVP
• The devices assigned by the system are usable devices. (Users can set a range of
devices which can be assigned automatically.)
The relation between the data types and the device types which can be assigned is described
below.
AH500
DVP
Data
type
Device assigned by Device assigned by Device assigned by Device assigned
users
the system
users by the system
BOOL
Contact M/SM or bit
in the device D/L/X/Y
Internal memory Contact M/X/Y Contact M
WORD D/L/X/Y/E/SR Internal memory D/E/F D
DWORD D/L/X/Y/E/SR Internal memory D/E/F D
LWORD D/L/X/Y/E/SR Internal memory D/E/F D
INT D/L/X/Y Internal memory None
DINT D/L/X/Y Internal memory None
LINT D/L/X/Y Internal memory None
REAL D/L/X/Y Internal memory D D
LREAL D/L/X/Y Internal memory None
STRING D/L/X/Y Internal memory None
STEP S S S S
COUNTER C/HC C C C
TIMER T T T T
The devices assigned to a symbol whose data type is ARRAY depend on the array
type specified. The array is composed of the devices starting from the device
ARRAY
assigned by users or the system, and the number of devices in the array conforms to
the size of the array.
The devices assigned to a symbol whose data type is ARRAY can not be SR/SM/E/F
devices.
*1. If the device assigned to a symbol is an internal memory in an AH500 series CPU module, users can not know the
actual device address.
*2. Please refer to section 6.2.3 for more information about ARRAY and STRING.
*3. Please refer to section 6.2.11 for more information about setting a range of devices which can be assigned
automatically in a DVP series PLC.
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