Terminal LFC (IEC 870-5) communication protocol

Supported device types and versions

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.

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.

Communication line configuration

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).

Communication line protocol parameters

Configuration line dialog box - tab Protocol parameters.
They influence some of the optional protocol parameters. The following line parameters can be set:

Table 1

Parameter

Meaning

Unit

Default value

Link Address

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

Communication station configuration

Communication protocol: Terminal LFC (IEC870-5).
The station address is a decimal number ranging from 0 up to 255. It represents the ASDU address in the protocol.

Communication station parameters

Configuration station dialog box - tab Protocol parameters.
They influence some of the optional protocol parameters. The following station parameters can be set:

Table 2

Parameter	Meaning	Unit	Default value
Retry Count	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
Retry Timeout	Timeout before resending a request if no response has been received.	ms	100 ms
Wait First Timeout	The delay after sending the request and before reading the response.	ms	100 ms
Wait Timeout	The delay between the response readings.	ms	500 ms
Max. Wait Retry	The maximum number of retries of the response reading.	-	6
No Data Timeout	A delay after the response without any data has come (Positive Confirmation).	ms	300 ms
Analog Constant	A constant to calculate addresses of measurements.	-	129
Analog Offset	A constant to calculate addresses of measurements.	-	40000
Digital Constant	A constant to calculate addresses of the signals.	-	501
Counter Constant	A constant to calculate addresses of the signals.	-	1026
Counter Offset	A constant to calculate addresses of the counters.	-	60000
DataClass Req. Compatibility	Compatibility of data class 1 and class 2 requests according to IEC870-5-101 specification. A value NO means that only "class 1 data" are requested.	YES/NO	NO
Send PostMortemData	Permission to send the received data with a timestamp as so-called post-mortem data (only to an archive).	YES/NO	YES