1. What is mobiLog/CAN™?

The basic idea behind the mobiLog system is to combine a handy mobile data acquisition unit for CAN bus data with a convenient modern PC interface. The PC program is used to prepare a measurement task and to analyze the collected data. The measurement itself is executed by the mobiLog system's mobile unit independently of the PC. During data acquisition, it is possible to display certain data in a customized form on the display screen of the mobile unit.


2. What data can be acquired using mobiLog/CAN™?

The mobiLog/CAN™ system has two CAN bus ports which can be configured separately so that telegrams can be received and, if needed, sent on two different CAN busses simultaneously. It is possible to record CAN telegrams in the sequence in which they occur (timestamp resolution: 1 ms) and/or to extract the content of CAN telegrams in real-time and to classify and then store them.

In addition to recording CAN data, mobiLog/CAN™ can exchange directionally configurable digital signals with the environment over 8 lines and, in addition, acquire two different positive analog voltages (with a common ground potential) using the built-in A/D converters. You can also se mobiLog/CAN™'s recording and display functions for the unit's digital I/Os and analog inputs.


3. Can the acquired data be viewed on the mobiLog/CAN™ unit?

Yes, mobiLog/CAN™ allows you to define online displays to view live data. You can customize these displays using text elements, lines, and other items facilitating the representation of values. You can integrate up to nine online displays into a measurement configuration and select (toggle) them during runtime.


4. I would like a specific online display to appear automatically when mobiLog is started. How can I do that?

By default, the online displays included in a measurement configuration are disabled when the measurement is started. The test set--the data object in the PC-managed project database which is used to generate a measurement configuration-- has an editor page named "Data flow" with a list named "Activated objects". To make sure an online display appears on the mobiLog screen when the measurement (i.e. monitoring) begins, enter its name in this list.


5. How is data exchanged between the mobiLog/CAN™ unit and the PC?

Either by establishing a serial connection between the PC and the mobiLog unit or by swapping the PC (PCMCIA) card. mobiLog/CAN™ uses static-RAM PC cards to store measurement configurations and to record data. The amount of data that can be stored on PC card depends on its capacity. Reading data directly from a PC card is considerably faster than a serial transmission when large amounts of recorded data have to be transferred to the PC.


6. I already have SRAM PCMCIA cards. Can I use them with mobiLog/CAN™?

Yes, if they are designed for a supply voltage of 5 V and consume less than 300 mA. The following card sizes can be used: 1, 2, 4, 8, and 16 MB.


7. How can the recorded data be analyzed?

After the recorded data has been transferred to the PC, the PC program can be used to interactively extract data from the recording. (The PC program allows you to select individual measurements contained in the recording file.) During analysis, the data can be visualized using the built-in features provided by the PC program (version 1.8 and higher) or exported into an output file which can then be processed in external analysis tools such as Excel or DIAdem.


8. Is it possible to view stored data on the mobiLog/CAN™'s LCD display?

No, data recorded by the mobiLog/CAN™ unit can only be displayed using the PC program.


9. Can mobiLog/CAN™ be used for bit-testing CAN transmissions?

No, mobiLog/CAN™ is only used to validate the content of CAN telegrams. It is not possible to verify if CAN bus stations transmit data in accordance with ISO 11898 or CAN 2.0. Since the actual CAN protocol is transparent to the functions provided by mobiLog/CAN™, incorrectly transmitted telegrams are not recorded by the unit.


10. Does the mobiLog/CAN™ unit have to be configured to receive CAN bus data?

Essentially yes, at least if telegrams are to be recorded or the content of individual telegrams is to be isolated and displayed on the device using the correct units of measurement.

Beginning with version 1.8, mobiLog/CAN™ offers a snooper mode that, for any given bus port, allows you to list all CAN IDs active on the bus when the unit is not under configuration control. Alternately, eight interactively selectable CAN IDs can be displayed as a hexadecimal byte sequence together with the current refresh rate of the telegram. Snooper mode offers yet another view in which the current CAN bus activity is represented as the dynamic frequency distribution of the telegrams across the ID address space.


11. What are history buffers and what are statistics buffers?

The mobiLog/CAN™ unit records data in buffers. Two basic types of buffers are used: history buffers and statistics buffers.

History buffers record events in the sequence in which they occur (timestamp resolution: 1 ms). In the configuration, you declare the buffer and specify the data objects to be recorded in it. If needed, more than one history buffer can be used in a measurement configuration. By default, mobiLog/CAN™ history buffers work as wrap-around buffers, i.e. when the buffer is full and recording continues, the oldest data is overwritten.

Statistics buffers are used to record the value distribution of certain data at runtime. When declaring the statistics buffer, you specify the data to be evaluated, the length of the acquisition interval and the number of classes within that interval.

In addition, mobiLog/CAN™ offers several options for each buffer type that allow you to modify how data is recorded.


12. What is the maximum amount of data that can be recorded using mobiLog?

This question only applies to history buffers since statistics buffers have a single 32-bit counter for each class and hence a fixed size, usually quite small. The maximum recording depth available in a history buffer depends on several parameters: capacity of the PC card and/or defined size of the buffer, number of data objects to be recorded in the buffer and frequency which with these data objects are updated. There are various way you can change these parameters when creating a measurement configuration. The User's Guide contains a formula that lets you calculate the approximate recording depth based on an average allocation of 16 bytes per entry.


13. In the mobiLog/CAN™ database, it is possible to declare variables. What are these variables used for?

Using configurable triggers, mobiLog/CAN™ can respond automatically to certain conditions. A trigger consists of a condition--an expression which determines when the trigger is executed--and a true/false action list which is processed based on the logical value of the condition. Action lists can also be used to calculate and assign new (output) data. To ensure a maximum degree of flexibility, this approach requires objects in which intermediate results can be stored, for instance to maintain data between two calls of a single trigger or to exchange data between different triggers. Variables can be declared for this purpose. The mobiLog/CAN™ unit can record variables like any other data.

On the back, the unit is equipped with a metal spring that allows it to be installed in a suitable enclosure. The unit measures 109 x 35 x 251 mm (4.29 x 1.38 x 9.88 in, L x H x D) and weighs approximately 850 g (1.87 lbs).

In addition, the unit has a serial port for transferring new configurations and recorded data, which allows for "hidden" installations.


15. I want mobiLog/CAN™ to come on when the vehicle is started or the test setup is turned on. What do I need to do?

The mobiLog/CAN™ unit can be turned on and off not only using the ON/OFF button but also using external signals. Each I/O connector has a pin which turns the unit on when voltage >5.1 V is applied, and off when the applied voltage is <2.2 V. If the unit is turned on using an external signal, it must be turned off the same way. Conversely, if the unit is turned on manually using the ON/OFF button, it can only be turned off the same way. All you need to do for the unit to begin measuring automatically is to add the "Autostart" property to the measurement configuration.


16. Is it possible to capture erroneous data in a CAN transmission and to determine what led to the error?

mobiLog/CAN™ allows the use of triggers in a measurement configuration. A trigger consists of the definition of a condition and a list of associated actions. You can use a trigger to wait for the occurrence of specific (erroneous) data and then terminate the recording in a history buffer. If, until that moment, all data potentially relevant in reconstructing the error history has been recorded in the buffer, you have a "frozen" history of the event.


17. Is mobiLog Year 2000 (Y2K) compliant?

PC program:

For operations in the PC program, with the exception of data analysis, references to absolute time are irrelevant. The absolute time values used for data analysis are the timestamps generated by the mobiLog unit (see below). The other absolute time values displayed or used by the program are derived directly from operating system services. The mobiLog PC program is Y2K-compliant provided the underlying operating system (Windows 95/98 or Windows NT) and the library functions of the Microsoft Visual C++ development environment used for access are Y2K-compliant as well.

mobiLog unit:

The mobiLog unit has an absolute time clock. The absolute timestamps generated by this clock and embedded in the recorded data show the year as four digits. This ensures that the start and end time of recording periods will be interpreted correctly beyond the turn of the millenium.

However, the absolute time clock of the mobiLog unit has two limitations:

In addition, please consider the following extreme case: If a history buffer recording goes on continuously for a long time, data points might receive timestamps that could be interpreted incorrectly. Within a recording period, relative timestamps are assigned to data. These timestamps are based on a 32-bit counter with a resolution of 1 millisecond. Every time the unit is turned on, this counter is restarted. At the beginning and at the end of a recording period, the current relationship between absolute time and relative counter is stored so that during offline analysis, the absolute time can be determined for each recorded value. In practical terms this means that if the unit is left on continuously for approximately 49.7 days, a counter overrun occurs, leading to inconsistent timestamps in a history buffer. As far as the intended applications of the mobiLog/CAN™ unit are concerned, this issue was assumed to be insignificant and therefore not corrected. To reiterate: Erroneous timestamps are not caused by long recording periods per se but instead occur when the unit is left operating continuously for more than 49.7 days.


18. In what fields is mobiLog/CAN™ currently used?

The following is a partial client list, with some examples of how mobiLog is used in their companies:

Daimler Chrysler AG
uses mobilog in their new product development department as well as for short-range test drives and vehicle endurance tests.

VDO Mannesmann AG
uses mobiLog for CAN simulation and controller development.

DEA AG, Shell AG and Mobil AG
use mobiLog for tests in the areas of lubricant development and motor and gear oil quality surveillance.


19. Where can I buy mobiLog/CAN™?

1. Germany

Software+Systeme Erfurt GmbH Fichtenweg 8 99198 Erfurt-Kerspleben Tel.: (+49) (0)36203 / 96-0 Fax.: (+49) (0)36203 / 96-333 E-Mail: info@sse-erfurt.de Web:    www.sse-erfurt.de	S+SE Software+Systeme Berlin GmbH Groß-Berliner-Damm 73c 12487 Berlin Tel.: (+49) (0)30 / 63 95 94-0 Fax.: (+49) (0)30 / 63 95 94-33 E-Mail: info@sse-berlin.com Web:    www.sse-berlin.com
ADMESS Elektronik GmbH Albrecht-Dürer-Straße 67292 Kirchheimbolanden Tel.: (+49) (0)6352 / 6091 Fax : (+49) (0)6352 / 1288 E-Mail: admess-elektronik@t-online.de

2. France

ISIT-France Didier Vidal ZI DES POUMADERES 32600 L'ISLE JOURDAIN Tel.: (+33) (0)56 207 / 2954 Fax : (+33) (0)56 207 / 2953 E-Mail: isit@isit.fr Web:   www.isit.fr