User manual

IEC61131 User and Reference Manual
April 22, 2008
585
The values change only when written by an application program or a communication
protocol.
Coil and Status Registers
Coil and status registers contain one bit of information, that is whether a signal is off or on.
For TelePACE firmware coil registers are single bits, which the protocols can read and write.
There are 4096 coil registers located in the digital output section of the I/O database. Coil
registers are contained within the DF1 16-bit addresses 0 to 255.
For TelePACE firmware status registers are single bits, which the protocols can read. There
are 4096 status registers located in the digital input section of the I/O database. Status
registers are contained within the DF1 16-bit addresses 256 to 511.
For ISaGRAF firmware coil registers are single bits, which the protocols can read and write.
There are 9999 coil registers located in the digital output section of the I/O database. Coil
registers are contained within the DF1 16-bit addresses 0 to 624.
For ISaGRAF firmware status registers are single bits, which the protocols can read. There
are 9999 status registers located in the digital input section of the I/O database. Status
registers are contained within the DF1 16-bit addresses 625 to 1249.
Coil and status registers are accessed 16 at a time or individually (in some commands)
using a bitmask. Writing a one to a bit within the 16-bit address turns the bit on. Writing zero
to the bit turns the bit off. If the register is assigned to an I/O module, the bit status is written
to the module output hardware or parameter.
Reading a coil or status register returns 1 if the bit is on, or 0 if the bit is off. The stored value
is returned from general purpose registers. The I/O module point status is returned from
assigned registers.
Input and Holding Registers
Input and holding registers contain 16-bit values.
Input registers are 16-bit registers, which the protocol can read. For TelePACE firmware,
there are 1024 input registers located in the analog input section of the I/O database. Input
registers are contained within the DF1 addresses 512 to 1535.
For ISaGRAF firmware there are 9999 input registers located in the analog input section of
the I/O database. Input registers are contained within the DF1 addresses 1250 to 11247.
Holding registers are 16-bit registers that the protocol can read and write. For TelePACE
firmware there are 9999 holding registers located in the analog output section of the I/O
database. Holding registers are contained within the DF1 addresses 1536 to 11534.
For ISaGRAF firmware there are 9999 holding registers located in the analog output section
of the I/O database. Holding registers are contained within the DF1 addresses 11248 to
21247.
Writing any value to a general purpose register stores the value in the register. Writing a
value to an assigned register, writes the value to the assigned I/O module.
Reading a general purpose register returns the value stored in the register. Reading an
assigned register returns the value read from the I/O module.
Accessing the I/O Database Using TelePACE
Ladder logic programs access the I/O database through function blocks. All function blocks
can access the I/O database. The function blocks in ladder logic use only the Modbus