C500TS502 Omron, C500TS502 Datasheet - Page 50

• Manufacturer Part Number: C500TS502
• Description: RTD INPUT MODULE
• Manufacturer: Omron

Specifications of C500TS502

• Leaded Process Compatible: No
• Peak Reflow Compatible (260 C): No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Interface to the PLC using 4-Word Mode
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44
Protocol
The 4-Word Mode Interface provides four status bits for handshaking during
communications between the module and the PLC. These bits are read and
written through PLC ladder logic and must be manipulated in the proper se-
quence for successful communication with the module. Two bits, PC Write
Finished and PC Read Finished, word N+1 bits 14 and 15, are set by the
PLC. The other two bits, TS Read Finished and TS Write Finished, word N+3
bits 14 and 15, are set by the module. See the table in the previous section
for a description of these bits.
Write Sequence Timing Diagram
The proper sequence of writing data to the module memory map is shown in
the following timing diagram. The sequence of the two events with PC Write
Finished and TS Read Finished must occur for data to be successfully trans-
ferred from the PLC to the module. Any deviation from this sequence will re-
sult in the module setting the Data Transfer Sequence Error Flag. To recover
from a Data Transfer Sequence Error the PLC must assert PC Read Fin-
ished.
1.
2.
3.
4.
Note
5.
6.
7.
PC Write Finished
TS Read Finished
TS Write Finished
PC Read Finished
Word N
Word N+1
Word N+2
Word N+3
PLC sets data to be written in Word N.
PLC sets the memory location address to be written in Word N+1 Bits
00-07.
PLC sets Word N+1 Bit 08 to indicate a write cycle to the module.
PLC sets PC Write Finished, Word N+1 Bit 14 indicating to the module
that new data is available.
When the module has read the data, it sets TS Read Finished,
Word N+3 Bit 14.
Seeing TS Read Finished go high, the PLC resets PC Write Finished.
Seeing PC Write Finished go low, the module then resets TS Read Fin-
ished ending the write cycle.
Steps 2, 3 and 4 may be performed simultaneously by writing the en
tire word N+1.
1
Don’t care
Don’t care
4
2,3
5
Flags valid
6
7
Section 5- -5