CV500BSC51 Omron, CV500BSC51 Datasheet - Page 46

• Manufacturer Part Number: CV500BSC51
• Description: Programmable Logic Controller
• Manufacturer: Omron

Specifications of CV500BSC51

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

4-4-3
Read Continuation
Flag
Using IORD(222) and IOWR(223)
Reading more than 128 Words
Note Bit 15 of C functions as the Read Continuation Bit.
The Data Read Completed Flag in the allocated CIO area words will be
turned OFF when IORD(222) has read the data from the GP-IB Interface
Unit’s buffer memory. If more than 128 words are being read, it will be neces-
sary to execute more than one IORD(222) instruction. It is easy to control the
read operation from the ladder program with the Read Continuation Bit
because the CIO area’s Data Read Completed Flag can be turned OFF only
after the last IORD(222) instruction has read all of the data from the Unit’s
buffer memory.
Bit 15 = 0: The last batch of data is being read.
Bit 15 = 1: There is data remaining to be read.
Example 1
When there are 128 or fewer words to read, execute IORD(222) with the Read
Continuation Bit OFF.
Example 2
When there are more than 128 words to read, execute IORD(222) with the
Read Continuation Bit ON.
Buffer memory
Data Read
Completed Flag
@IORD(222)
15
14
Starting read address in buffer memory
W
C
D
Turned ON by Unit.
Example: Receiving 30 bytes (15 words) of data
Data
reception
C: Starting read address in buffer memory (0000 to 0253 Hex)
with Read Continuation Bit in bit 15 (See note.)
IORD(222)
Data
reception
IORD(222)
Starting read address: 0154 Hex
Number of words to receive: 15
Turned OFF by Unit. (See note.)
Section 4-4
0
29