User manual

Chapter 4 Configuration
Page 77 ©February 2009
Note: If analog values are read to and written from an integer file in an SLC or Micrologix CPU,
integer files contain 16 bit signed values. These represent values in the range -32768 to 32767. The
data values from the 105U modules are treated as 16 bit unsigned values. To convert the data from
an analog input, move the data from the integer file to a long file (MOV command) then mask out
the high 16 bits (MVM with mask value FFFF). This will result in a long integer value in the range 0
to 65535.
Alternatively, use a long integer file type to transfer the analog value as a long integer in the range 0-
65535.
Pulse I/O
Pulse counts from the remote 105U modules are shown as a 16-bit register. When the register
rolls over, from ‘FFFF’ (hex), the next value will be ‘0001’. The register will only have a value
of ‘0000’ when the remote module starts up, and the previous count is lost. This value will
indicate that the counter has reset.
Note: The values from the 105G module are 16 bit unsigned values. When they are copied to the
Integer file in the PLC, they will be treated as 16 bit signed values. These values may be
converted to the original (unsigned) values using the MOV and MVM instructions described in
the previous section (Analog I/O). Again, using a Long Integer type will avoid this problem.
500 CPU (SLC and Micrologix) file types and addressing
The 105G provides a linear address space of 10,000 data words. This is compatible with PLC2
addresses, but does not match the addressing used by the 500CPU modules (SLC and
Micrologix). These address data by file number and file offset. To address an I/O register, L, in
the 105G, use DF1 file number L / 100, with the remainder value (L % 100) as the DF1 file
offset. For example, to read I/O register 2643 in the 105G, read from file number 26, offset 43.
4.9 Fieldbus Configuration
All 105G modules (except MD1) have separate internal hardware comprising the Fieldbus
Interface, consisting of a separate microprocessor and appropriate hardware for the network
connection. This Fieldbus Interface handles all fieldbus communications, and transfers I/O in the
Fieldbus Interface Registers to/from the fieldbus. Conversely, the 105G Radio Interface handles
all radio communications, and transfers I/O in the Radio Interface Registers to/from the radio
WRITE
RADIO
INTERFACE
I/O
DATABASE
I/O REGISTERS FIELDBUS
LOCATIONS
READ
FIELDBUS
INTERFACE
RADIO
DRIVER
DATA BUS
ANTENNA