Is ISObus Really Plug And Play?

In a test unprecedented in its detail and complexity, profi assembles the “state of the art” in ISObus terminals and ag implements to see if they function in up to 54 different working configurations.

While manufacturers praise their spirit of co-operation, saying ISObus compliance delivers benefits, detractors complain that this compatibility doesn’t always materialize.

So, to find out what’s happening we bring together six tractors, three retrofit in-cabin terminals and six implements — all supposedly speaking the same ISObus language.

For the test we took tractors from Case IH, Deutz-Fahr, Fendt, Deere, MF and New Holland. The various implements came from Accord, Dammann, Deutz-Fahr, Pttinger and Vicon. At the same time we also sourced retrofit ISObus terminals from Kverneland, Mller-Elektronik and WTK — the OEM supplier for Deutz-Fahr tractors. WTK terminals, complete with joystick, are also sold by Landmec Pttinger in the U. K. Full details are listed in the ISObus combinations table.

This is a fair representation of the ISObus terminals and tractors that were available in mid-’08. A full list of currently approved equipment is at starting the test, we ensured all the software on the terminals was fully updated with the latest versions. Three implements came from Kverneland including a fertilizer spreader, precision drill and round baler. These units were tested alongside a Deutz-Fahr baler, Pttinger wagon and Dammann sprayer.

We installed the three retrofit terminals to three tractors in addition to their existing ISObus equipment. All nine terminals and six implements were then also swapped around to create every possible tractor/ terminal/implement combination. So, by the end of the test, each tractor had been fitted with every terminal and hitched to all the implements, producing a total of 54 tested combinations.


The test routine kicked off with the “bootup” procedure. This looked at how quickly and easily the terminal detected a new implement and loaded the software, as well as booted up and found a previously used machine. After the system had recognized the ISObus implement, we carried out a stationary test. A field test would have been too time consuming for all of the 54 combinations.

The stationary test checked the following functions on these various implements: fertilizer spreader — open/close outlet; precision drill — fill cell wheels; sprayer — open/ close sprayer master valve and switch sections; round baler — baler pick-up lower/raise and knives in/ out; and forage wagon — pick-up lower/raise

All 54 test combinations passed this “plug and play” swap-around test. The ISObus terminals’ ability to detect the attached implement and upload the appropriate software worked well.

Admittedly, some of the initial uploads took longer than others. But that’s only to be expected, as the required time relates directly to the complexity of the electronics installed on the individual implement.

In our test, for example, the upload for the Dammann ANP 6000 sprayer took 60 to 120 seconds before any terminals were able to display the pages, whereas it took just 20 to 60 seconds on other implements.

Some of the screens show how the bootup is progressing. Dammann, for example, displays a clock face with a moving hand, while Deutz-Fahr’s AFIS terminal has a progress bar. These are very helpful guides, particularly during a lengthy upload because the operator can begin to wonder whether the system has frozen.

After initial connection, users don’t have to endure a long wait, because the implement’s own “job computer” instructs the terminal to save these settings when it’s shut down. So the next time the operator activates the system, all implement functions are immediately available and start-up time is cut to 10 to 20 seconds.


Overall, the test didn’t produce any spectacular results. None of the systems failed the test, although we did uncover a few subtle differences.

All the terminals uploaded and displayed the pages correctly. The only problems we encountered were with the Fendt Vario and MF Datatronic. These had difficulties displaying Dammann’s sprayer interface, which appeared only in black-and-white despite both having colour screens and Dammann also providing “colour data.”

Further tester investigations traced the trouble back to the fact that both the Fendt and MF terminals process only 16 colours, while the information from the Dammann sprayer produces 256-colour or black-and-white interface data. The ISObus standard provides for black-and-white, 16-colour and 256-colour displays.

Kverneland and Pttinger produce both 256-colour and 16-colour data, which is why the Fendt and

Profimagazine tested a number of tractor electronic displays to see if you really can plug in a baler or sprayer or other implement and have them work together. The answer: Yes, you can.

MF terminals don’t have problems displaying their pages.

The screen on Fendt’s terminal, however, can appear rather pixelated, while the MF display is, by comparison, pleasantly sharp and clear. This is probably down to the MF’s ability to also display video input from on-board cameras — a useful addition but nothing to do with the ISObus standard. Case IH, New Holland and the WTK terminals can also display video.

The AFIS unit on the Deutz-Fahr tractor, which is built by WTK, was the only one on test to display in just black-and-white. Although it complies with ISObus, it’s now rather outdated. Even so, the menus are laid out well. WTK offers a new terminal, the Field Operator 300, which does have a colour screen.

When it came to assessing the Case IH and New Holland units, we discovered hardly any differences between the two systems — except for the names. Case IH’s terminal is badged AFS Pro 600, while the New Holland version is called IntelliView Plus II. Both terminals have 26.4 cm (diagonal) colour touch screens that provide “virtual” buttons. The screen displays are sharp and clear.

The main difficulty we encountered with both units was the considerable reflection in sunlight, and this was made worse by grubby fingerprints on the screen. Antireflection film may help here.

A plus for the Case IH and New Holland terminals is that they do provide the useful additional feature of presenting a full range of tractor performance information — forward speed, fuel consumption and area — in a separate window to the left of the implement window. While this extra info is handy, there’s often too much text to fit into one column.

The ISO 11783 standard determines that all ISObus terminals should have at least six push buttons, which must relate to a so-called “soft-key” function on the screen.

The Fendt terminal on test did not meet these requirements. Only five out of this terminal’s six buttons relate to a custom function — the sixth button is the “Escape” key. To be fair, though, Fendt was the first manufacturer to fit an ISObus terminal, and it stands alone as being standard (no extra cost) on all tractor models from the

415 Vario upwards. Moreover, the new Fendt 900 Series terminal does have six function keys and obviously represents the shape of Fendt things to come.

Many ISObus implements offer the option of assigning machine functions to the standard Fendt joystick. Examples include the Accord Exacta TC 3300 ISObus fertiliser spreader or the Pttinger Europrofi5000 D forage wagon. Users can also customise the displays on the John Deere GreenStar 2600 terminal and Dammann MC 1 (identical to Mller-Elektronik). These screens are also large enough to display tractor info along with ISObus implement functions and GPS automatic steering.

The Mller terminal has push buttons— a total of 10 “F keys” and six more keys for scrolling and switching between menus, while John Deere’s Greenstar 2600 has a touch screen to which the operator can also connect an external keypad.

The Kverneland Tellus ISObus terminal is generally impressive, providing 10 flexible membrane keys — ten function keys and more for scrolling and editing entries. Its colour screen is easy to read and isn’t affected by sunlight reflections. Our only concern relates to the build quality of the plastic box that houses the electronics.


Our profi ISObus “plug ‘n play” test was a resounding success. All of the systems provided trouble-free operation in as many as 54 different tractor/implement/ terminal configurations. We did record differences in upload time, screen display characteristics and operation, but we proved the terminals could control all our implements on their own. In practice, however, the sprayers and forage wagons need an ISObus joystick to simplify use.

At first we had our suspicions regarding our connection success. Perhaps, we wondered, all the manufacturing companies had conspired to supply only equipment that they knew would work together. But, no, that wasn’t the case. We had already anticipated that issue and sourced our kit through dealers. As a result, we can say with confidence that our test proves the ISObus sceptics wrong: This technology is delivering the compatibility that farmers and contractors need, along with the freedom to choose their implements from a wide selection of manufacturers.

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