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This communication supports data reading and writing by IEC870-5-101 communication protocol with special modifications. TCP/IP UDP network communication or a serial communication on Serial or SerialOverUDP Device Redundant communication line can be used.
An implementation Implementation according to IEC870-5-101 standard:
- Originator ASDU address - omitted.
- ASDU address - it is 1 byte and represents a station address. A different ASDU address of each station on the same line is required.
- Cause of transmission - it is 1 byte (it does not contain Originator ASDU address).
- Information object address - 2 bytes, it represents I/O tag address.
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- Communication line category: Serial, TCP/IP-UDP, SerialOverUDP Device Redundant
- UDP Parameters:
- The parameters of primary server or secondary one are required.
- Host: string max. 80 characters – a server name in the INET form (the name or numerical address a.b.c.d).
- Port: UDP port number (1 to 65535).
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Configuration line dialog box - tab Protocol parameters.
They influences influence some of the optional protocol parameters. The following line parameters can be set:
Table 1
| Parameter | Meaning | Unit | Default value |
|---|
| Communication line address (1 byte). | - | 1 |
| Communication Error Timeout | Timeout defined for the check of communication on the line (or on the lines of primary or backup communication in case of UDP communication). If communication does not work longer than it is this value, the values of all communication stations on the line will be transferred to StCOMERR state. | ms | 10 sec |
| Kotva |
|---|
| komunikacna_stanica |
|---|
| komunikacna_stanica |
|---|
|
Communication station configuration
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- Communication protocol: Terminal LFC (IEC870-5).
- Station The station address is a decimal number ranging from 0 up to 255. It represents the ASDU address in the protocol.
| Kotva |
|---|
| param_protokolu_stanice |
|---|
| param_protokolu_stanice |
|---|
|
Communication station parameters
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Configuration station dialog box - tab Protocol parameters.
They influences influence some of the optional protocol parameters. The following station parameters can be set:
Table 2
| Parameter | Meaning | Unit | Default value |
|---|
|
Number of the call retry when some communication error occurs| Maximum count of request retries. If no response returns after a request had been sent, the station's status will change to a communication error. | - | 2 |
|
A delay between the call retries when some communication error occurs| Timeout before resending a request if no response has been received. | ms | 100 ms |
|
Time of the first waiting for response after the call has been sent| The delay after sending the request and before reading the response. | ms | 100 ms |
|
A reading of till its completingNumber retry | retries of the response reading |
till its completing| . | - | 6 |
| A delay after the response without any data has come (Positive |
Quittung| Confirmation). | ms | 300 ms |
| A constant to calculate |
an address a measurement| measurements. | - | 129 |
| A constant to calculate |
an address a measurement| measurements. | - | 40000 |
| A constant to |
calculate an address | calculate addresses of the signals. | - | 501 |
| A constant to |
calculate an address | calculate addresses of the signals. | - | 1026 |
| A constant to |
calculate an address | calculate addresses of the counters. | - | 60000 |
DataClass Req. Compatibility |
A compatibility | Compatibility of data class 1 and class 2 requests according to IEC870-5-101 specification. A value NO means that only |
data called| requested. | YES/NO | NO |
| Permission to send |
a | the received data with a timestamp as so-called post-mortem data (only to an archive). | YES/NO | YES |
I/O tag configuration
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A possible I/O tags: Ai, Ao, Ci, Di, Dout, Qi
The address consists of two parameters - Object and Value.
These parameter parameters are used to calculate the address (in the range 0 to 65535) according to these formulas:
- The calculation of complete address for Ai, Ao tags (the measurements):
Address = ((Object - 1) * ACONST) + Value + AOFFSET - The calculation of complete address for Di, Dout tags (the signals):
Address = ((Object - 1) * DCONST) + Value
- The calculation of complete address for Ci tag (the counters):
Address = ((Object - 1) * CCONST) + Value + COFFSET
As regards Dout tags, you can set Value address (i.e. Object and Value). A basic Basic address data is required at in writing. Value address is used to update I/O tag value at reading.
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- An alternate highest bit RES of Control Field is used which signalized to signalize data receiving from an active server (RES=0) in a redundant system. Otherwise, data come from a passive server and they are ignored (RES=1).
- An The arrival of the binary value TRUE to the object with address 65007 (so-called USAN bit) signalized a transition of I/O tag values of all stations to the value with "Weak" flag, i.e. all values become invalid.
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