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MICROTEL 700 communication protocol

Supported device types and versions
Communication line configuration
Communication station configuration
Alternative communication path
I/O tag configuration
Redundant system
Errors and problems
Detail implementation of protocol
Literature
Changes and modifications
Document revisions

Supported device types and versions


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Communication line configuration


Global parameters:

Key word Full name Description Unit / size Default value
SCAN Scan Permanent passive mode (Scan only) only for data reading (mode 2). YES/NO NO
MOXAT Moxa Timeout Setting of timeout for change to other communication device on SerialOverUDP Device Redundant line. If the valid data are not received from communication device till timeout, the other device is used (backup or primary, if it is configured). 20 sec

Communication station configuration


  • Communication protocol: Microtel 700.
  • Station address is a number within the range 1 to 253. Do not use the addresses 0, 254 and 255. They are filtered because they often occur at the beginning of response (error in transmission system).

Parameters of station protocol

Dialog window of station configuration - tab "Protocol parameters".

Table 1

Key word Full name Description Unit / size Default value
RC Retry Count Number of retry calls when error in communication occurs. - 2
RT Retry Timeout Delay between retry call if a communication error occurs. ms 500 millisec.
WFT Wait First Timeout The first waiting for a response after sending a call. ms 300 millisec.
WT Wait Timeout Delay between the readings of a response until it is completed. ms 200 millisec.
MWR Max Wait Retry Number of retry response reading until it is completed. - 20
MODULE_CNT Module Count Maximum number of modules that are required in one call. The value must be in the range of 1 to 5. If not, the default value is used. - 5
INV_MOD Inversed Modules An analyze of sectors that have been changed (the function COS - CHANGE OF STATE) is done in inverse order:

bit 0 LSB - modules 0..7,
bit 1 - modules 8..15, ...
bit 7 MSB - modules 56..63.

YES/NO NO
AHOST Alternative Path Host(s) 1, 2 The configuration of so-called alternative communication path.
It is IP address, hostname or several IP addresses/hosts separated by commas or semicolon. The total number of alternate communication paths entered under these parameters is 12.
Empty value means than an alternative path is not used.
   
APORT Alternative Path Port 1,2 UDP ports to which data will be sent when using the alternative communication path.   0
APRC Alternative Path Retry Count Number of retry call if the alternative communication path is used. - 2
APUT Alternative Path Use Timeout After the elapse of the defined time since the start of using alternative communication path, the viability of communication through standard path is tested again according to the communication line configuration.
Value 0 turns off the testing (communication uses an alternative path while it works).
Note: The parameter value also changes the order of trying the alternative communication paths in case of their malfunction. If the value is nonzero, the standard communication path is always tried after an alternate communication path. If the value is zero, then all alternative communication paths are tried first and only then the standard communication path.
sec 600

Alternative communication path


With help of protocol parameters you can configure so-called alternative communication path for the particular station (only for SerialOverUDP Device Redundant and TCP/IP-UDP lines). If the communication via standard path elapses, the throughput of communication via the alternative path (when configured) is tested. The communication via the alternative path runs through TCP UDP form that is identical with that in SerialOverUDP Device Redundant line. The usage of alternative path is signalized by FLB flag and combination of FLN, FLO, FLP flags in the station.

I/O tag configuration


Possible I/O tag: Ai, Ao, Ci, Co, Di, Do, Qi.

The I/O tags of Ci and Co type are not used for a usual operation but only for a servicing. They display and record the values of modules in a raw form without the conversion to a physical value. The values of modules are 16-bit, thus a numerical in the range of 0 to 65535.

The structure of I/O tag address:

  • All types of values require the setting of the basic address, so-called module, which is the number in the range of 0 to 63.
  • Set the bit number in the range of 0 to 15 for Di, Do and 0 to 14 for Qi.
  • For Ai and Ao - insert data for conversion of a raw form to the physical value, so-called "RTU table index", and minimum/maximum of physical value. RTU table index defines the range of raw values which is used in next recalculation (see Table 2). 

Table 2

RTU table index Min / Max Note
1.  0-20 mA 0 .. 3600 It is used for Ai inputs.
2.  4-30 mA 720 .. 3600 It is used for Ai inputs.
3.  Pt100 -500 .. 1000 It is used for Ai values.
4.   -4095 .. 4095 Not applicable.
5.   -4095 .. 4095 Not applicable.
6.   -500 .. 1000 Not applicable.
7.  4-20 mA 800 .. 4000 It is used for Ao outputs.
8.  0-20 mA 0 .. 4000 It is used for Ao outputs.

The conversion of Ai inputs from the raw values "Raw_Value" to the physical value (Fyzikal_VALUE) is done according to this formula:

Scale = (Fyzikal_MAX - Fyzikal_MIN) / (RTU_MAX - RTU_MIN)

Offset = ((Fyzikal_MIN * RTU_MAX) - (Fyzikal_MAX * RTU_MIN)) / (RTU_MAX - RTU_MIN)

Fyzikal_VALUE = (Raw_Value * Scale) + Offset

The conversion of Ao outputs from the physical value to the raw one is done by the inverse function:

Raw_Value = (Fyzikal_VALUE - Offset) / Scale

The calculation of value "Scale" is modified to 0 (zero) so the recorded value is 0. This situation occurs if a user configures the physical minimum same as the maximum.

I/O tags of Qi type may use a special setting for the conversion of 2-bit input value to the required status one. The implicit conversion is stated in Table 3.

Table 3

Binary value Meaning
00 (0) FAILED (v D2000 "ERROR")
01 (1) CLOSED (v D2000 "OFF")
10 (2) OPEN (v D2000 "ON")
11 (3) MOVING (v D2000 "TRANS")

Redundant system


This protocol supports two modes of activity:

  1. The connection to "hot" server (HS). The protocol executes the active communication by sending the request for data according to configuration. 
  2. The connection to "stand-by" server (SBS). The protocol just reads and analyzes the received data. To get the line and all the station to this status at any time, you can use the protocol parameter SCAN in the configuration of at least one station.

The change from SBS -> SS is done with a transient phase. It means that data are read during one minute to detect an inactivity on the communication line and whether the previous D2000 KOM, connected to HS server, has changed to mode 2.

Errors and problems


The error messages, mentioned below, may occur during the start or communication. It is recommended to activate the monitoring of communication in the configuration of line for easier identification of problem. You can choose it from these levels:

  • Monitor (at least)
  • Monitor & Disk (recommended)
  • Disk (recommended)

When you set "Monitor & Disk" or "Disk", the file "line_name.LOG" occurs in the subdirectory "\TRACE" in application directory on the computer with the running communication process. This file contains all the debug and error messages.

Error: >MTEL700 : Station address error: 'station_name' !
Description: The address of this station is not a number from the required range. Carry out the change in configuration and modify the address according to article Communication station configuration.
Error: >MTEL700 : Invalid min/max value, difference is zero, point: 'point_name'! 
Description: The address configuration of I/O tag contains the identical number for both physical maximum and minimum. The result of this could be a wrong conversion to a physical value.
Error: >MTEL700 : Error in address, point: 'point_name'!
Description: The address of I/O tag contains the wrong data. Check the validity and range of all address parameters of this I/O tag.
Error: >MTEL700 : High Security Relay, St: 'station_name', Point: 'point_name', Module: module, Bit: bit, Unknown DATA2 response nr
Description: The wrong response to the function HIGH SECURITY RELAY, the recording of Do point value. Contact Technical Support of Ipesoft.
Error: >MTEL700 : High Security Relay, St: 'station_name', Point: 'point_name', Module: module, Bit: bit, Module is faulty or missing !
Description: The response to the function HIGH SECURITY RELAY, the recording of Do point value. The values can not be written into this module.
Error: >MTEL700 : General Purpose Output Error, St: 'station_name', Point: 'point_name', Module: module , Module is faulty or missing !
Description: The response to the function GENERAL PURPOSE OUTPUT, the recording of Ao point value. It is impossible to write to this module.
Error: >MTEL700 : Detected zero module count in response, St: 'station_name', Addr: station_address, requested Module: module, requested MCount: module_count
Description: No modules (no valid data) have been detected in the response to the function DATA STREAMING.
Error: >MTEL700 : Detected non identically module count in response, St: 'station_name', Addr: station_address, requested Module: module_number, requested MCount: requested_module_count, acquired MCount: acquired_module_count
Description: The module count in the response to the function DATA STREAMING is different than it was required in the call. Missing data.
Error: >MTEL700 : Cannot get understanding response, St: 'station_name', Addr: station_address, requested Module: module, requested MCount: module_count
Description: The clear response to the function DATA STREAMING cannot be obtained. Received data were illegible.
Error: >MTEL700 : No response to request, St: 'station_name', Addr: station_address, requested Module: module, requested MCount: module_count
Description: No response to the function DATA STREAMING has been received. The station does not answer.

Errors in the passive phase of communication

D2000 KOM connected to SBS server could display the following error messages:

Error: >MTEL700-SCAN : Line: 'line_name', Unknown command response! Data buffer: data
Description: Unknown function - response. Data are ignored.
Error: >MTEL700-SCAN : Line: 'line_name', Unknown command request! Data buffer: data
Description: Unknown function - call. Data are ignored.
Error: >MTEL700-SCAN : Line: 'line_name', Module count number too big! Data buffer: data
Description: The module count in the received message DATA STREAMING exceeded the permitted count. Data are ignored.
Error: >MTEL700-SCAN : Line: 'line_name", BCH ERROR! Data buffer: data
Description: Wrong checksum of the received message. The message is ignored.
Error: > Microtel 700 : Scan task, Line 'line_name', received valid data during scan stop timeout !
Description: During transition phase after connecting to HS, the valid packets of Microtel 700 were received. This status may be transient and may take only several seconds. In case of any problems, contact Technical Support of Ipesoft.

Detail implementation of protocol


Supported and used functions: 

COMMAND 3 - Change of State Scanning

Scanning of the changes in the block of modules since the last data reading. This function is not used after starting the communication (all the values are unknown) and for the reading which comes after the communication error. In these situations, the value of all configured I/O tags is read.

COMMAND 2 - Data Streaming

The value reading of the modules. It optimizes the reading of the configured (configured only!) adjacent modules en bloc until completing of MODULE_CNT by one datagram.

COMMAND 7 - High Security Relay

The writing of the new value for binary I/O tag of Do type. It is executed in two phases.

COMMAND 4 - General Purpose Output

The writing of the new value for I/O tags of Co or Ao type.

Literature


  • MICROTEL 700 Telemetry.

Changes and modifications


  • January 9, 2008 - Alternative communication path.
  • September 19, 2017 - Multiple hosts can be entered in alternative communication path, TCI/IP-UDP line is supported.

Document revisions


  • Ver. 1.0 - September 2, 2003 - Document created
  • Ver. 1.1 - January 9, 2008 - Document updated
  • Ver. 1.2 - September 19, 2017 - Document updated
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