Socket Service Status |
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Data Received/Requested Flag
Results Storage Flag
TCP Connection/UDP Open Flag
Opening Flag
Receiving Flag
Sending Flag
Closing Flag
Bit | Switch | Status | Manipulated | Unit operation |
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0 | Opening Flag | ON | Unit | Turns ON when an open request is received. |
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| OFF |
| Turns OFF when open processing has been completed. |
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1 | Receiving Flag | ON |
| Turns ON when a receive request is received. |
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| OFF |
| Turns OFF when receive processing has been completed. |
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2 | Sending Flag | ON |
| Turns ON when a send request is received. |
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| OFF |
| Turns OFF when send processing has been completed. |
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3 | Closing Flag | ON |
| Turns ON when an close request is received. |
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| OFF |
| Turns OFF when close processing has been completed. |
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13 | Data Received Flag | ON |
| Turns ON when data from a remote node has been received at an |
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| open TCP socket. |
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| OFF |
| Turns OFF when receive processing has been requested for an |
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| open TCP socket. |
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14 | Results Storage Error | ON |
| Turns ON if there is an error in the Results Storage Area specified |
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| for the socket service request command to the Ethernet Unit. |
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| This flag turns ON at the same time as any of the services request |
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| processing flags (bits 0 to 3) turn ON again (i.e, at completion of |
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| processing). |
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| OFF |
| Turns OFF when the next request is received. |
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15 | TCP Connection/UDP | ON |
| Turns ON when UDP open processing has been completed or when |
| Open Flag |
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| a TCP connection is made. |
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| OFF |
| Turns OFF when close processing has been completed. (Will |
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| remain OFF when open processing ends in an error.) |
6-6-2 DM Area Allocations
The following DM Area words are allocated in the CPU Bus Unit Area in the
DM Area. The beginning word m is calculated by the following equation.
Beginning word m = D30000 + (100 x unit number)
■Number of Bytes Received at TCP Socket (Ethernet Unit to CPU Unit)
The number of bytes of data saved in the reception buffer at the TCP socket is stored in the TCP Connection Status words. The Data Received Flag in the CIO Area turns ON/OFF in response to the status of these words. When the dedicated control bits (switches) are manipulated or the receive request is sent by executing the CMND(490) instruction, the values of these words are temporarily set to 0000 hexadecimal.
If any data remains in the reception buffer after the receive request processing is complete, the number of bytes is stored in the Number of Bytes Received at TCP Socket and the Data Received Flag turns ON again.
Receive requests should be executed after confirming that the required data is contained in the number of bytes received.
m+1 to m+8
15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Number of Bytes Received (0000 to 07C0 hexadecimal)
111
