2-1SectionSpecifications
14
Backup Time vs. TemperatureA lithium battery in the CPU Unit is used to back up the contents in the user pro-
gram area, the READ/WRITE area in the Data Memory (DM), Hold Relay (HR),
the Auxiliary Memory Relay (AR), and in the data area of the Counter (CNT). The
deterioration of the lithium battery capacity depends on the ambient tempera-
ture. The standard service life is 12 years under an ambient temperature of 40_C
when operating 8 hours a day.
If the power supply is interrupted after the lithium battery capacity has deterio-
rated, the contents in the user program area, the READ/WRITE area in the Data
Memory (DM), Hold Relay (HR), Auxiliary Memory Relay (AR), and in the data
area of the Counter (CNT) may be lost. Even if the contents of the CPU Unit’s
program area are lost, however, the user program and DM read-only contents
(including the one in the PC Setup area) stored in flash memory will be read to
the CPU Unit’s user program area when the SRM1 is next started up.
2-1-3 CompoBus/S Communications Specifications
Item Specifications
Communications method CompoBus special protocol
Transmission method Multi-drop, T-branch
Baud rate High-speed
communications
mode
750 kbps
Long-distance
communications
mode
93.75 kbps
Modulation method Baseband method
Code method Manchester coding method
Maximum number of connectible
terminals 32: 16 IN and 16 OUT
16: 8 IN and 8 OUT
Number of points per frame 256 (128 IN and 128 OUT), when maximum number of connectible terminals
is 32.
128 (64 IN and 64 OUT), when maximum number of connectible terminals is
16.
Communications High-speed 0.8 ms, when maximum number of terminals is set to 32.
cycle time communications
mode 0.5 ms, when maximum number of terminals is set to 16.
Long-distance 6.0 ms, when maximum number of terminals is set to 32.
communications
mode 4.0 ms, when maximum number of terminals is set to 16.
Communications function Cyclic transfer only (no message communications)
Error control checks Manchester code check, frame length check, parity check, two-transfer
comparison
Communications
distance High-speed
communications
mode
Main line length: 100 m max.
Branch line length: 3 m max.
Total branch line length: 50 m max.
Long-distance
communications
mode
Main line length: 500 m max.
Branch line length: 6 m max.
Total branch line length: 120 m max.
Cable Vinyl-clad VCTF
JIS C 3306 Two 0.75 mm2 conductors (2 signal wires)
Flat cable Four 0.75 mm2 conductors (2 signal wires and 2 power supply wires)