Protocol : IEC 60870-5-101


 

The protocol IEC 60870-5-101 and IEC 60870-5-104 is also available in the LIAN 98 Software,
running under the operating system Microsoft® Windows® ( 32/ 64 bit ).

see : LIAN 98 Protocol Router, Simulator and Analyzer


 

IEC 60870-5-101 : Parameterization

 

 

CDE adapter :

Transmission rate :

Modulation mode:

Data byte :

Stop bit :

Parity :

Time out :

Link address field :

ASDU address field :

Object address field :

Origin address :

switch setting PCM

50 - 115 200 baud

pulse-code-modulation asynchronous

8 bit (variable)

1 bit (variable)

even (variable)

250 msec (variable)

0 - 2 with and without  structure

1 - 2 with and without  structure

1 - 3 with and without  structure

yes / no

 

Link transmission procedure
B :

  Balanced
  

Point to point

If balanced transmission procedure is used, each station may initiate message transfers. The balanced mode is restricted to "point-to-point or multiple point-to-point".
Balanced transmission can be used in full duplex mode.

Balanced transmission can be used in full duplex transmission

U :
 
Unbalanced

Party line

Unbalanced transmission is used in SCADA systems in which a master station controls the data traffic by polling outstations sequentially.

The master station (master) is the primary station that initiates all message transfers while outstations are secondary stations (slaves) that may transmit only when they are polled.
The unbalanced mode can be used generally, but must be used in party line configuration.

 

Telegram structure

IEC TCP 101 protocol standard admits exclusive frame format FT 1.2 defined in IEC 60870-5-1 (Transmission frame formats). Formats with fixed and variable block length are admitted. Also the single control characters A2H and E5H are used. The transmission of data bytes  takes place after the principle "LSB first".

It is an asynchronous protocol with hamming distance = 4. The sequence of user data characters is terminated by a 8 bits checksum. The checksum is the arithmetic sum over all user data octets.

Frame with variable length :
Frame is used for data transmission of user data between controlling and controlled station.

 

Frame with fixed length :

Frame with fixed length is normally used for link layer services. In special cases  frame with fixed length can be used as a confirm frame instead of single character.

 

Single character:

Single character is normally used to confirm data on link services and to confirm user data.

E5 H = ACK : Positive acknowledgement
A2 H = NACK: Negative acknowledgement


Link control field :

RES/ DIR Unbalanced mode : reserved
Balanced mode : Physical transmission direction

DIR = 1 : Data from controlling (Master) to controlled (Slave) station
DIR = 0 : Data from controlled (Slave) to controlling (Master) station

PRM Primary message

0 = message from a secondary (controlled) station
1 = message from a primary (controlling) station

FCB Frame count bit  - primary message

alternating bit for consecutive  SEND/ CONFIRM or REQUEST/ RESPOND message per station. The primary station alternate the FCB bit for each new SEND/ CONFIRM or REQUEST/ RESPOND transmission service directed to the same secondary station.

If an expected reply is timed out (missing) or grabled, then the same SEND/ CONFIRM and REQUEST/ RESPOND service is repeated with the same frame count bit.

In case of reset commands the FCB bit is always zero, and upon receipt of these commands the secondary station will always be set to expect the next frame primary to secondary with FCV = valid (FCV = 1) to have the opposite setting of FCB, i.e. FCB equal to one

FCV Frame count bit valid - primary message

0 = alternating function and FCB bit is invalid
1 = alternating function and FCB bit is  valid

SEND/ NO REPLY services, broadcast messages and other transmission services that ignore the deletion of duplication or loss of information output do not alternate the FCB bit and indicates this by a cleared FCV bit.

ACD/ RES Unbalanced mode : Access demand - secondary message
Balanced
mode : Reserved

There are two classes of message data provided, namely class 1 and 2.

0 = no access demand  on transmission of data class 1
1 = access demand for class 1 data transmission

Class 1 data transmission is typically used for events or for messages with high priority.
Class 2 data transmission is typically used for cyclic transmission or for low priority messages.

DFC Data flow control - secondary message

0 = more messages are acceptable
1 = further messages can cause a data overflow

Secondary (responding) stations indicate to the message initiating (primary) station that an immediate secession of a further message may cause a buffer overflow.

Function code :
 

Funktion codes of the control-field in a message sent from the primary station ( PRM = 1 )

Function Frame type Service function FCV
 0 Send/ CONFIRM expected Reset remote link 0
 1 Send/ CONFIRM expected Reset user process 0
 2 Balanced : Send/ CONFIRM expected Test function for link 1
 3 Send/ CONFIRM expected User data 1
 4 Send/ NO REPLY expected User data 0
 5 Reserved    
 6 Reserved for special use by agreement    
 7 Reserved for special use by agreement    
 8 Unbalanced : Request access demand / RESPOND expected Expected response specifies access demand 0
 9 REQUEST/ RESPOND expected Request status of link 0
10 Unbalanced : REQUEST/ RESPOND expected Request user data class 1 1
11 Unbalanced :REQUEST/ RESPOND expected Request user data class 2 1
12 Reserved    
13 Reserved    
14 Reserved for special use by agreement    
15 Reserved for special use by agreement    

 

Function codes of control-field in a message sent from the secondary station ( PRM = 0 ) :

Function Frame type Service function
  0 CONFIRM ACK: Positive acknowledgement
  1 CONFIRM NACK: message not accepted, link busy
  2 Reserved  
  3 Reserved  
  4 Reserved  
  5 Reserved  
  6 Reserved for special use by agreement  
  7 Reserved for special use by agreement  
  8 Unbalanced : RESPOND User data
 9 Unbalanced : RESPOND NACK: requested data not available
10 Reserved  
11 RESPOND Status of link or access demand
12 Reserved  
13 Reserved for special use by agreement  
14   Link service not functioning
15   Link service not implemented

 

Link adress fields :

Link transmission procedures are using a control field and the optional address field.

The link address is a number for a communication link which is used for the communication lines out from a controlling station. It is only used as an address in the communication network itself, an shall not be a part of total address of a data point.

According to the standard this parameter can consist of 0,1 or 2 octets. 0 is valid only for balanced mode.


Type identification :

Process information in monitor direction :

1 Single-point information M_SP_NA_1
2 Single-point information with time tag M_SP_TA_1
3 Double-point information M_DP_NA_1 
4 Double-point information with time tag M_DP_TA_1
5 Step position information M_ST_NA_1
6 Step position information with time tag M_ST_TA_1
7 Bitstring of 32 bit M_BO_NA_1
8 Bitstring of 32 bit with time tag M_BO_TA_1
9 Measured value, normalized value M_ME_NA_1
10 Measured value, normalized value with time tag M_ME_TA_1
11 Measured value, scaled value M_ME_NB_1
12 Measured value, scaled value with time tag M_ME_TB_1
13 Measured value, short floating point value M_ME_NC_1
14 Measured value, short floating point value with time tag M_ME_TC_1
15 Integrated totals M_IT_NA_1
16 Integrated totals with time tag M_IT_TA_1
17 Event of protection equipment with time tag M_EP_TA_1
18 Packed start events of protection equipment with time tag M_EP_TB_1
19 Packed output circuit information of protection equipment with time tag M_EP_TC_1
20 Packed single-point information with status change detection M_PS_NA_1
21 Measured value, normalized value without quality descriptor M_ME_ND_1

Amendment A1: Telegrams  with long time tags ( 7 octets )

30 Single-point information with time tag CP56Time2a M_SP_TB_1
31 Double-point information with time tag CP56Time2a M_DP_TB_1
32 Step position information with time tag CP56Time2a M_ST_TB_1
33 Bitstring of 32 bit with time tag CP56Time2a M_BO_TB_1
34 Measured value, normalized value with time tag CP56Time2a M_ME_TD_1
35 Measured value, scaled value with time tag CP56Time2a M_ME_TE_1
36 Measured value, short floating point value with time tag CP56Time2a M_ME_TF_1
37 Integrated totals with time tag CP56Time2a M_IT_TB_1
38 Event of protection equipment with time tag CP56Time2a M_EP_TD_1
39 Packed start events of protection equipment with time tag CP56time2a M_EP_TE_1
40 Packed output circuit information of protection equipment with time tag CP56Time2a M_EP_TF_1

Process information in control direction :

45 Single command C_SC_NA_1
46 Double command C_DC_NA_1
47 Regulating step command C_RC_NA_1 
48 Set point command, normalized value C_SE_NA_1
49 Set point command, scaled value C_SE_NB_1
50 Set point command, short floating point value C_SE_NC_1
51 Bitstring of 32 bit C_BO_NA_1

System information in monitor direction :

70 End of initialization M_EI_NA_1

System information in control direction :

100 Interrogation command C_IC_NA_1
101 Counter interrogation command C_CI_NA_1
102 Read command C_RD_NA_1 
103 Clock synchronization command C_CS_NA_1
104 Test command C_TS_NB_1
105 Reset process command C_RP_NC_1
106 Delay acquisition command C_CD_NA_1

Parameters in control direction :

110 Parameter of measured value, normalized value P_ME_NA_1
111 Parameter of measured value, scaled value P_ME_NB_1
112 Parameter of measured value, short floating point value P_ME_NC_1
113 Parameter activation P_AC_NA_1

File transfer :

120 File ready F_FR_NA_1
121 Section ready F_SR_NA_1
122 Call directory, select file, call file, call section F_SC_NA_1 
123 Last section, last segment F_LS_NA_1
124 Ack file, ack section F_AF_NA_1
125 Segment F_SG_NA_1
126 Directory F_DR_TA_1

 

The program SIMO is able to process user-defined telegram types in the range between 1-127, provided they have the same general message format as the IEC 60870-5-101 standard. 

Variable structure qualifier :

The SQ bit specifies the method of addressing of the following information objects or elements.

SQ = 0

Each single element or a combination of elements is addressed by the information object address. The ASDU may consist of one or more than one equal information objects. The number of objects is binary coded and defines the number of the information objects.

SQ = 1

A sequence of equal information elements (e.g. measured values of identical format) is addressed by the object address. The information object address specifies the associated address of the first information element of the sequence. The following information elements are identified by numbers incrementing continuously by + 1 from this offset. The number of objects is binary coded and defines the number of the information elements. In case of a sequence of information elements only one information object per ASDU is allocated.

Cause of transmission :

The cause of transmission directs the ASDU to a specific application task (program) for processing.

ASDUs in control direction are confirmed application services and may be mirrored in monitor direction with different cause of transmission.

P/N

The P/N-bit indicates the positive or negative confirmation of activation requested by the primary application function. In the case of irrelevance the P/N-bit is zero.

T

In addition to the cause the test-bit defines ASDUs which were generated during test conditions. It is used e.g. to test transmission and equipment without controlling the process.

Originator address :

The originator address directs mirrored ASDUs and interrogated ASDUs in monitor directions (e.g. interrogated by a genaral interrogation) to the source that activated the procedure.

If the originator address is not used and there is more than a single source in a system defined, the ASDUs in monitor direction have to be directed to all relevant sources of the system. In this case the specific affected source has to select its specific ASDUs..

Common address of ASDU :

The common address is associated with all objects in an ASDU. The global address is a broadcast address directed to all stations of a specific system. ASDUs with a broadcast address in control direction have to be answered in monitor direction by ASDUs that contain the specific defined common address  (station address). According to the standard this parameter can consist of 1,2 or 3 octets.

Information object address :

The information object address is used as a destination address in control direction and a source address in monitor direction.

The third octet is only used in case of structuring the information object address to define unambiguous addresses within a specific system. In all cases the maximum number of different object addresses is limited with  65 535 (as for two octets). If the information object address is not relevant (not used) in some ASDUs, it is set to zero.

 


Simulation mode

With the implemented simulation mode the program SIMO offers besides the recording of telegrams the possibility of using the PC as a counter-station.

 

Please note that the simulation was completely revised as of version 3.56.5. Corresponding to the used LIAN-DOS version please read the equivalent section.  

 

Simulation with LIAN-DOS up to version 3.56.4

The simulation can be started via the command 'RTI [time window] [repetitions]. There is no difference between primary- and secondary station or balanced- and unbalanced transmission. The program orientates to the function code and the PRM bit in the control field of the link layer.

The parameter [time window] determines the  time  in 1/10  seconds  that  the  program SIMO as primary station  at most has to wait for an acknowledge before the transmission is repeated. Via the parameter  [repetitions] it is defined  how many times the above procedure is to be repeated. The call  'RTI 10 3' ,for example, defines a monitoring time of  one second and up to 3 repetitions. 

If   'RTI' without parameter is entered, the time monitoring is  switched off  and there are no repetitions. As long as the program SIMO  is waiting for an acknowledge no further  telegrams are  included in the send list. By entering  'RTI' again during running simulation, the simulation is switched off.

The program SIMO as secondary station transmits dependent on the function code of the primary station automatically acknowledges according to the message buffers listed in the table.  The corresponding telegrams must be of course edited in the declared TDB buffers.

Allocation of TDB (Transmit data buffer)

number commentary telegram type data (hexadecimal)
492

493

494

495

496

497

498

499

CONFIRM fnct 00       492

CONFIRM fnct 01       493

CONFIRM fnct 02       494

CONFIRM fnct 03       495

Action        fnct 08      496

RESPOND fnct 09       497

RESPOND fnct 10       498

RESPOND fnct 11       499

10H fixed length

10H fixed length

10H fixed length

10H fixed length

10H fixed length

10H fixed length

10H fixed length

10H fixed length

10  80  00  00  00  16

10  00  00  00  00  16

10  00  000  00  16

10  00  000  00  16

10  0B  00  00  00  16

10  0B  00  00  00  16

10  09  00  00  00  16

10  000  00  00  16

Course of simulation

Program SIMO as secondary station

Receipt of telegrams from the primary station
function transmitted from the primary station SIMO transmits TDB
0 SEND-CONFIRM expected

standardizing of the communication unit of the  secondary station.

buffer 492
1 SEND-CONFIRM expected

standardizing of the user procedure

buffer 493
2 SEND-CONFIRM expected

reserved for  symmetrical transmission procedures 

buffer 494
3 SEND-CONFIRM expected

user data

buffer 495
4 SEND-no respond expected

user data

 
5, 6, 7 reserved for particular use  
8 REQUEST after access demand

the access demand is fixed in the respond

buffer 496
9 REQUEST-RESPOND expected

query of state of communication unit 

buffer 497
10 REQUEST-RESPOND expected

query of user data class 1

buffer 498
11 REQUEST-RESPOND expected

query of user data class  2

buffer 499
12 - 15 reserved for particular use  

Program SIMO as primary station

 Receipt of  telegrams from the secondary station
function transmitted from the secondary station  actions in SIMO 
0 CONFIRM

positive  acknowledge  (ACK)

switch off timer 
1 CONFIRM

negative acknowledge (NACK)

switch off timer 
2 - 7 reserved for particular use  
8 RESPOND

user data

switch off timer 
9 RESPOND

NACK, called up data not available

switch off timer 
10 RESPOND

NACK, message from the link layer not arrived 

switch off timer 
11 RESPOND

state of communication unit  or access demand 

switch off timer 
12 - 15 reserved for particular use  

 

Transmission of telegrams to the secondary station
function telegram type / service function SIMO transmits 
0 SEND-CONFIRM expected

standardizing of the communication unit of the secondary station

FCB set back

FCB, FCV = 0

ACK function 0

start timer

1 SEND-CONFIRM expected

standardizing of the user procedure

FCB, FCV = 0

ACK function 0

start timer

2 SEND-CONFIRM expected

reserved for  symmetrical transmission procedures 

FCB invert

FCV = 1

ACK function 0

start timer

3 SEND-CONFIRM expected

user data

FCB invert

FCV = 1

ACK function 0

start timer

4 SEND-no response expected

user data

FCB, FCV = 0
5, 6, 7 reserved for particular use  
8 REQUEST after access demand

access demand fixed in response

FCB, FCV = 0
9 REQUEST-RESPOND expected

query of state of communication unit

FCB, FCV = 0

ACK function 11

start timer

10 REQUEST-RESPOND expected

query of user data class 1

FCB invert

FCV = 1

ACK function 8

start timer

11 REQUEST-RESPOND expected

query of user data class 2

FCB invert

FCV = 1

ACK function 8

start timer

12 - 15 reserved for particular use  

 


Extended simulation with LIAN-DOS as of version 3.56.5

All parameters needed for the simulation are set in the program LIAN via menu item  <settings | simulation>  ( see section  5.3.5.16 settings - simulation )

 

RTI (Master)-simulation
Link address

This link address is the target address and will be inserted in each telegram to be sent during master simulation.

Exception for unbalanced mode :
The link address ( 255 for an one octet address or 65 535 for a two octet address) of a broadcast command is entered in the TDB buffer telegram. 

ASDU address

This ASDU address is the target address and will be inserted in each telegram to be sent during master simulation.

Exception for unbalanced mode :
The ASDU address
( 255 for an one octet address or 65 535 for a two octet address) of a broadcast command is entered in the TDB buffer telegram. 

Originator address  All telegrams to be sent during RTI simulation will be provided with this origin address.
Response timeout

The IEC 870-5-101 standard specifies a fixed link time-out interval to be used for repeated frame transmissions. The time-out interval and maximum number of retries are configurable and appropriate values will depend on the transmission system.

This parameter determines the time in 1/10 seconds  that the program SIMO as primary station  at most has to wait for an acknowledge before the transmission is repeated.

Number of frame retries Via this parameter it is defined  how many times the transmission is to be repeated when the acknowledge is missing. 
Enable Station initialization

yes / no

The controlling station synchronizes its link with the controlled station by transmitting "Request status of link" and "Reset of remote link". The controlled station responds with "Status of link" and "ACK" respectively, and when the "ACK" is received in the controlling station the link connection is established.

The telegram "Request status of link" ( PRM=1, function 9 ) must be stored in the TDB buffer 470 and the telegram "standardizing of the communication unit" ( PRM = 1, function 9 ) must be stored in the TDB buffer 471.

Scan delay

( only unbalanced )

 

This parameter determines the time in 1/10 seconds  that the program SIMO delays the next request ( data class 1 or 2 ).

The telegram "Request user data class 1" ( PRM = 1, function 10 ) must be stored in the TDB buffer 473 and the telegram "Request user data class 2" ( PRM = 1, function 11 ) must be stored in the TDB buffer 474.

 

RTU (Slave)-simulation
Link address

This link address is the source address and will be inserted in each telegram sent during RTU simulation.

ASDU address

This ASDU address is the source address and will be inserted in each telegram sent during RTU simulation.

Originator address All telegrams to be sent during RTU simulation will be provided with this origin address ( = target address ).
Response timeout

( only balanced )

The IEC 870-5-101 standard specifies a fixed link time-out interval to be used for repeated frame transmissions. The time-out interval and maximum number of retries are configurable and appropriate values will depend on the transmission system.

This parameter determines the time in 1/10 seconds  that the program SIMO as primary station  at most has to wait for an acknowledge before the last transmission is repeated.

Number of frame retries
( only balanced )

Via this parameter it is defined  how many times the transmission is to be repeated when the acknowledge is missing ( only balanced ). 

Enable Station initialization

( only balanced )

yes / no

The controlling station synchronizes its link with the controlled station by transmitting "Request status of link" and "Reset of remote link". The controlled station responds with "Status of link" and "ACK" respectively, and when the "ACK" is received in the controlling station the link connection is established.

The telegram "Request status of link" ( PRM=1, function 9 ) must be stored in the TDB buffer 470 and the telegram "standardizing of the communication unit" ( PRM = 1, function 9 ) must be stored in the TDB buffer 471.

End of initialization yes / no

The telegram M_EI_NA_1 ( ID 70, COT 4 ) must be stored  in the TDB buffer 479

Generate ACTCON respond yes / no

Is this parameter set to 'yes' automatically ACTCON ( COT 7 ) or. DEACTCON Respond ( COT 9 ) is transmitted during RTU simulation after the receipt of an Activate Command ( COT 6 ) or Deactivate Command ( COT 8 )

Generate ACTTERM respond yes / no

Is this parameter set to 'yes' automatically an ACTTERM Respond ( COT 10 ) is transmitted with time delay during the RTU simulation after the receipt of an Activate Command ( COT 6 ) . 

ACTTERM delay time

This parameter determines the time in 1/10 seconds  that the transmission of ACTERM Respond ( COT 10 ) is delayed.

 

Allocation of TDB Buffers (Transmit data buffer) for the primary station

TDBnum Commentary Frame Data

470

471
 

...

473

474

...

479
  

Request status of link

Standardizing of the communication unit

 

Request user data class 1

Request user data class 2

 

M_EI_NA_1
( End of initialization ) 

10H

10H
 

 

10H

10H

 

68H
 

DIR 0 PRM 1 FCB 0 FCV 0 FKT 09

DIR 0 PRM 1 FCB 0 FCV 0 FKT 00
 

 

DIR 0 PRM 1 FCB 0 FCV 1 FKT 10

DIR 0 PRM 1 FCB 0 FCV 1 FKT 11

 

DIR 0 PRM 0 ACD 0 DFC 0 FKT 03  // PtP
DIR 0 PRM 0 ACD 0 DFC 0 FKT 08  // MuP

 

Allocation of TDB Buffers (Transmit data buffer) for acknowledges of the secondary station

TDBnum Commentary Frame Data
480

481

482

483

...

485

486

487

488

489

490

491

492

493

494

495

CONFIRM on Function 00

CONFIRM on Function 01

CONFIRM on Function 02

CONFIRM on Function 03

...

Service not available

Service not available

Service not available

ACTION on Function 08

RESPOND on Function 09

RESPOND on Function 10

RESPOND on Function 11

Service not available

Service not available

Service not available

Service not available

10H

10H

10H

E5H

...

10H

10H

10H

10H

10H

10H

10H

10H

10H

10H

10H

DIR 0 PRM 0 ACD 0 DFC 0 FKT 00

DIR 0 PRM 0 ACD 0 DFC 0 FKT 00

DIR 0 PRM 0 ACD 0 DFC 0 FKT 00

E5H CONFIRM ACK

...

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

DIR 0 PRM 0 ACD 0 DFC 0 FKT 11

DIR 0 PRM 0 ACD 0 DFC 0 FKT 11

DIR 0 PRM 0 ACD 0 DFC 0 FKT 09

DIR 0 PRM 0 ACD 0 DFC 0 FKT 09

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

DIR 0 PRM 0 ACD 0 DFC 0 FKT 15

 


Simulation procedures

 

Simulation of the communication services :

LIAN DOS orientates to the function code and the PRM bit in the control field of the link layer :

The parameter [response timeout] determines the time in milliseconds that LIAN DOS after transmitting a primary message  at most has to wait for an acknowledge before the transmission is repeated. Via the parameter [number of frame retries] it is defined how many times the message is to be repeated. As long as the program is waiting for an acknowledge no further telegrams are included in the send list.

LIAN DOS transmits dependent on the function code of a primary message automatically acknowledges according to the defined TDB buffer numbers above. The corresponding frames must be of course edited in the declared TDB buffers.

The program also alternates the FCB bit for each new SEND/ CONFIRM or REQUEST/ RESPOND transmission service directed to the same secondary station. Thus the primary station keeps a copy of the frame count bit per secondary station. In case of reset commands the FCB bit is always zero, and upon receipt of these commands the secondary station will always be set to expect the next frame primary to secondary with FCV = valid ( FCV = 1 ) to have the opposite setting of FCB.

If master simulation and balanced transmission mode are selected the DIR bit is set to 1 in the control field of the link layer for all sent telegrams.

.

Station initialization

The station initialization will be done by LIAN DOS automatically when the master (RTI)- or the slave (RTU) simulation is started.

The primary station synchronizes its link with the secondary station with the transmission "Request status of link" and "Standardizing of the communication unit". The secondary station responds with "Status of link" or "ACK". When the primary station receives "ACK" the link is established.

 

Simulation of the application functions :

Data acquisition by polling
( unbalanced )

Data acquisition is used with unbalanced data transmission procedures to update controlling station with actual states of process variables in controlled stations. The controlling station  perform polling by interrogating (Function code 10, 11) controlled station sequentially. Controlled station may transmit only when they are polled.

Cyclic polling is done automatically by LIAN DOS if the Master (RTI)- Simulation is started and party line ( unbalanced ) is set via the configuration.

Cyclic data transmission

Cyclic data transmission is used to provide a continuous updating function of current values of process variables with balanced and unbalanced transmission procedures.

A cyclic data transmission in LIAN DOS is to be done by sending manually cyclic frames via the SIMO command window (see Command [SZ] ) or defining and using a not terminated send sequence list ( see  edit send sequence ).

Acquisition of events
( unbalanced )

There are two classes of data specified, class1 data contains spontaneous data and class 2 data contains cyclic data . Also specified is the link service "Request user data class 2" (function code 11) to be used for polling controlled stations. Two consequences are then possible in each controlled station when the poll telegram is received.

No spontaneous data are available
In this case the link layer of the controlled station responds by a NACK, i.e. either the single character A2H or the fixed frame telegram "Requested data not available", and the controlling station continues its poll procedure by polling the next controlled station.

Spontaneous data are available
In this case the controlled station also responds by the fixed frame NACK telegram "Requested data not available" (funtion code 9), but this time with the ACD bit set, indicating that spontaneous data are available and waiting for transfer. The controlling station then sends a "Request user data class 1" (function code 10) telegram, and the controlled station responds by transmitting an event ASDU.

A spontaneous data transmission in LIAN DOS is to be done by sending manually spontaneous data frames via the SIMO command window  (see command [SS] ) or defining and using a send sequence list ( see edit send sequence  ).

General interrogation

The general interrogation application function is used to update the controlling station after the station initialisation procedure or when the controlling station detects a loss of information.

The general interrogation function of the controlling station requests the controlled station to transmit the actual values of all its process variables. The interrogation procedure completes when the controlling station receives an End of Interrogation message.

The information transfer is triggered by an interrogation command ( ID 100, COT 6 ) message from the controlling station to the controlled station, which responds with an interrogation confirmation ( ID 100, COT 7 )  message. The controlled station transmits the interrogated information by means of one or more monitored information ASDUs. The last information ASDU is then followed by an interrogation termination message ( ID 100, COT 10 ), indicating that all information has been transferred.

The confirmation message ( ACTCON ) and the interrogation termination message ( ACTTERM ) will be transmitted during RTU simulation by LIAN DOS automatically when this is parametrized in the simulation list ( Program LIAN: Menu item <Settings | Simulation> ). One or more monitored information ASDUs in order to simulate the process can be also transmitted when the user has defined a corresponding action filter ( see  Action filter ) via program FIPP.

Clock synchronization

Clocks of controlled stations are initially synchronised by the controlling station after initialisation and then re-synchronized periodically.

A CLOCK SYNCHRONIZATION command message (ID 103) containing the full current clock time is sent from the controlling station. After the execution of the clock synchronization the controlled station generates a confirmation message which contains the local time before synchronization.

( Clock synchronization is not supported by LIAN DOS at this time )

Command transmission

The controlling station sends a SELECT command message (ID 45-50) to the controlled station, which responds by a SELECT confirmation message if it is ready to accept the announced command. The time from the SELECT command to the SELECT confirmation is controlled by a configurable time-out interval.

A successful select procedure may then be deactivated by a "Break off command". This command is transmitted by a BREAK OFF command message and the controlled station responds by a BREAK OFF confirmation message. The time between these messages is controlled by a timeout.

If appropriate, an EXECUTE command message is sent to the controlled station, which responds by an EXECUTE confirmation message (positive if the specified control action is about to begin, otherwise negative). This procedure is also non interruptible and the time from the EXECUTE command to the EXECUTE confirmation is controlled by a configurable time-out interval. An EXECUTE termination message is issued from the controlled station when the command application procedure is completed successfully. The addressed equipment should now change its state, and the new state is indicated to the controlling station by a spontaneous data message when reached.

The conformation message ( ACTCON ) for the SELECT and the EXECUTE command respectively the EXECUTE termination message ( ACTTERM ) will be generated automatically during RTU simulation by LIAN DOS when this is parametrized in the simulation list ( Program LIAN: Menu item <Settings | Simulation> ). A spontaneous data  message in order to simulate the state change of the device can be also transmitted when the user has defined a corresponding action filter ( see Action filter ) via program FIPP.

Transmission of integrated totals

Integrated totals are values that are integrated over a specified period of time.

Parameter loading

Parameter loading is used to change predefined parameters, e.g. deadband values that define when analogue measurements are to be transmitted. Parameters can only be transmitted from the controlling station as a result of an operator command.

To load a new parameter value, the controlling station sends a PARAMETER LOAD command message (ID 110-112) to the controlled station. The parameter load command is then acknowledged by the controlled station by transmitting a PARAMETER LOAD confirmation message.

Test procedure

The test procedure is used to check the complete loop from the controlling station to the controlled station and back.

A test command is initiated by the controlling station by sending a TEST command message (ID 104). This ASDU is mirrored by the controlled station as a TEST confirmation message. The controlling station compares the transmitted TEST message to the mirrored message, and if the messages are identical the test result is positive.

File transfer

File transfers from controlled stations are mainly used to inform the controlling station of events that occurred and that involved the registration of extensive data records.

File transfers in command direction are mainly used for downline loading of parameter lists of programs.

Acquisition of transmission delay

Acquisition of transmission delay is an alternative procedure for determining the time correction in clock synchronization commands.

 


Plain text display format

 

The output for each channel can be manipulated over the menu item <Format> in the programs SIMO, TRAP and TDEP. To optimise the output one can distinguish between three plain text settings for protocols with long telegrams ( e.g. IEC protocols )

Plain text F 1

Plain text F 2

Plain text F 3

the complete telegram ( link layer + identification + information ) is displayed

output of  link layer and data unit identifier ( no information )

output of the information objects only

 


Transmission errors

 

Error checks during receive by LIAN DOS :
  • per character the start bit, the stop bit and the even parity bit.
  • per frame the start character, the frame checksum and the end character and  the length (2  bytes ) and second start character in frames with variable lengths.
*F:BCCode : The telegram check sum in the BCC byte is incorrect.
*F:Blocklength : The stop byte ( 16H ) is missing or set wrongly.
*F:TelFormat : The repetition of the length or the start sign in the telegram header is faulty.
*F:TimeOut :

Within a telegram, there may be no pause between characters. The sensitivity can be parameterized in the program LIAN DOS.

*F:SYNC : The receive routine initially searches for 68H, 10H, E5H or A2H. Every other character is given an asterisk '*' in SIMO and a synchronization error is noted against it in the protocol.
*F:Overflow :

Error message by the UART

*F:Parity :

Error message by the UART

*F:Start/Stop :

Error message by the UART

*F:VSQ :    The information stored in the field 'variable structure qualifier' is absurd ,probably caused by wrong field length with the  parameterization.

 

Error checks during simulation by LIAN DOS  ( as of version 3.56.5 ) 
*F: DIR-Bit ! Balanced : Direction bit is wrong.
*F: PRM-Bit ! Primary message bit is wrong.
*F: FCB-Bit ! Frame count bit is wrong.
*F: FCV-Bit ! Frame count bit valid is not correct set.
*F: un-reset ! No station initialization is done yet, but in the message the FCV bit is already set.
*F: unexpected ! The respond was not expected.

 


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Manual LIAN DOS


LIAN DOS Protocol Simulator and Analyzer
© Copyright 1991, 1996, 2001, 2006-2010 by Werner Mayr. All Rights reserved.