In the last article I showed the RS and HotWire and the installation of the RS in a car. Now it’s time to find out how to program the RS using the HotWire PC software.

Quite a few things have changed since I wrote the last article. I’m running a different 12th scale car using 1S LiPo and a booster (the RC Dynamics one), and am now using a Tekin Redline 10.5 motor. None of these affect the actual operation of the HotWire software, but they definitely alter the setups! Tekin themselves have also released HotWire version 4, otherwise known as Vegas 2. This includes firmware version 203 for the RS, which has new features and definite benefits for stock motors, in other words making them faster! The article is based on these versions.

I am going to concentrate on the use of the RS in stock 12th scale as that is what I usually run, though most of the article will also be useful to other classes and motors.

Do not plug the HotWire interface into the PC yet, wait until you have installed the software. The drivers are installed along with the software and these have to be present before connection the HotWire.

The RS comes with firmware version 180 installed, so the first thing most people will want to do is to get the latest version. This can be found at http://www.teamtekin.com/hotwire/vegas/index.html. You first have to register. After registration you are emailed instructions on how to download the software. If you try to do this and it takes you back to the registration screen again, chances are you don’t have cookies enabled in your web browser, so enable them and go through the process again. You will end up with a file called TekinHotWire_4_0_0.zip on your computer. You need to unzip this to a folder to get to the install files. When you have done this you need to run the setup.bat file to install or upgrade the HotWire software.

Now you can plug in your HotWire interface for the first time. Windows will go through it’s device detection process and the device will be installed. After this has completed unplug the HotWire from the PC again. The reason for this is because you have to connect the HotWire to the RS before connecting it to the PC, it will not work otherwise.

Time to do this now. Plug the HotWire into the RS, then the HotWire into the PC. Then run the HotWire software. For a while you will get the following screen while the software finds the HotWire.

If the software cannot find the HotWire the following message will be shown.

There are several possible reasons for this but the usual ones are either not making sure the USB cable is plugged fully into the HotWire, or plugging things together in the wrong order as described above. If you have a green light on the HotWire, and a single red light on the RS it has been connected correctly. If any of these lights are missing or all the red lights are lit on the RS it hasn’t.

When the HotWire is discovered the default RS setup screen will be shown as below.

The red squares and rectangles are buttons. It is hard to see the text on these without hovering the mouse over them. The text will turn to white and can then be read easily. The button on the bottom right is the Advanced button. Clicking this will open the interface out and show further options as below.

The first section we are interested in is the one that lets us upgrade the firmware on the RS. This is shown in more detail here.

The Current Version area shows the current firmware on the RS. This will initially say 180 so most people will want to upgrade. The process of upgrading is simple. First select the firmware version to be upgraded to from the list. A new button will now appear below the list labelled Update ESC. Click this button and follow the instructions given. That’s it! Just one thing to remember, don’t unplug anything until the entire process is completed. If you do this you have the possibility of ending up with an RS that will need to go back to Tekin to be reset. You have been warned!

After upgrading exit the HotWire software and unplug everything. It is important to then recalibrate the RS to your transmitter as this will have been reset during the upgrade process. Then reconnect everything and run the software again.

Now for a description of the various sections and sliders use to program the RS. All of the sliders look like the one on the left. Above and below each slider is a button which can be used for fine adjustment of each slider. Directly above the slider it’s current value is shown. The slider pointer itself can be dragged up and down by the mouse. You can also click on the sliders themselves above or below the pointer which will change the values by different increments depending on the range of the slider.

If you hover the mouse over the title of the slider a hint will be shown giving a more detailed description of the function of the slider. This sometimes also gives hints on how the function should be used.

If you right click on the slider you get a menu where it is possible to select from a range of preset values for the function.

Drag Brake – This controls the amount of brake that is applied when the throttle is a neutral. In 12th scale this is often set to 0, though with some stock motors there is little rolling resistance and in these cases a value between 5 and 10 can be useful. Drag Brake and Push Control are mutually exclusive; if you use one set the other to 0.

Reverse Strength – This controls the maximum speed of reverse. In 12th scale this would not be used as reverse is not permitted.

Brake Strength – This controls the level of braking that is available. In 12th scale the brakes are rarely used except to stop the car at the end of the race. Just in case I have to use them though I usually set the value just below 100 in order to smooth the out a little but still be able to stop the car quickly in the event of an emergency.

Neutral Width – This is the amount the throttle stick or trigger is moved before the RS thinks it is not at the neutral position any more. This is a case of personal preference, though it is not advisable to set a value below 5 or the RS may not be able to register the neutral value correctly. Transmitter neutral values can drift and there needs to be some margin to allow this.

Motor Type – This sets both the type of motor used, brushed or brushless, and also whether the speed control is runs with brakes only or with reverse. For 12th scale stock this should be set to brushless forward only, BL-FW.

Throttle Profile – This is the same as setting a throttle curve on your transmitter. Setting 3 is a linear response. Higher numbers give a positive curve, lower ones a negative curve.

Voltage Cutoff – When running LiPo batteries it is advisable to set a voltage cutoff to prevent accidentally over discharging of the cells. If this happens they are permanently damaged. preset values are available for different LiPos or a custom cutoff voltage level can be set. This slider is disabled when the 1S LiPo box is checked.

The next set of sliders is different depending on whether the speed control is set to run in dual mode or sensored only mode. There are also some settings that are common to both. The common ones will be described after the differences. In dual mode they are as seen here.

Timing Advance – This sets the amount of added timing to the motor. It is not measured in degrees but as a percentage. 100 means 100 percent, but is somewhere between 25 and 30 degrees of added timing. It is useful to set this to 100 even when running sensored only as if the sensor cable is damaged the speed control will switch to sensorless mode and run the motor with this timing advance setting.

Current Limit – This limits the amount of current that is sent to the motor. It can be useful to tame the power of a modified motor.

The sensored only sliders are shown here.

Timing Boost – This is the amount of extra timing added to the motor. This is shown in degrees. The way this timing is introduced to the motor depends on the RPM settings which will be described later.

Turbo Boost – This is another method of adding timing to the motor, and is also shown in degrees. This is introduced after a certain amount of time at full throttle.

Turbo Delay – The amount of time you have to be at full throttle before the Turbo Boost starts to come in. The speed it comes in is set by the Turbo Ramp setting described later.

Now for the common settings.

Push Control – This gives a small amount of throttle for a short time when the trigger or stick has been returned to neutral. It is similar to trimming your transmitter to have a small amount of throttle, but as it turns off after a short time it has the advantage of not having to hold the car on the brakes at the start. Remember that Drag Brake and Push Control are mutually exclusive.

Reverse Motor – This changes the normal rotation of the motor to clockwise. Not much use on a 12th scale unless you custom build a car with the motor the other way round to normal!

1S LiPo – When this is not checked, the voltage cutoff slider is used to set a cutoff voltage. The RS assumes it will be powered via the main battery and checks this for the correct voltage to power the RS. When this is checked, the voltage slider has no effect. The RS assumes it will be powered via the RX lead and will check this for correct voltage to power the ESC. A specific 1S cutoff will also operate.

Sensored and Dual Mode check boxes – Only one of these can be set at a time. When Sensored is checked the speed control runs in sensored mode, using the sensor wire and the hall sensors in the motor to detect the position of the rotor. This enables all the advanced timing functions of the RS so is the usual setting for stock classes. Dual Mode runs the motor in sensored mode when the throttle is initially opened, but then switches to sensorless. This is more often used in the modified classes as it is more efficient than sensorless only.

Now for the functions that have been added with the release of the 203 firmware. It is possible to set the motor RPMs that the timing boost starts and finishes coming in. The End RPM has to be set first. Once this value has been set the button underneath, labelled Calc RPMs has to be clicked. This will calculate all the possible Start RPMs for the End RPM that has been set and show them in the Start RPM list. One of these values then has to be selected.

An example. The values shown here are a start RPM of 2758 and an end RPM of 10516. If timing boost has been set to 40 degrees, the timing set by this will not start to come in until the motor has reached 2758 RPM, and will have the full 40 degrees of timing when the motor reaches 10516 RPM.

Turbo Ramp defines the speed at which Turbo Boost comes in. There are three possible values, 1.0 being the slowest and 3.0 being the quickest. Overall, Turbo Boost will not come in until you have been on full throttle for the amount of time set by  the Turbo Delay setting, and the will come in at the speed defined by the Turbo Ramp setting until it reaches the timing value set by the Turbo Boost slider. This is most useful on tracks with a long main straight where the car is reaching maximum speed early. Turbo Boost can be used to effectively give the car a “second gear”. On typical 12th scale tracks with an up to 30m straight I have rarely found Turbo Boost to be necessary if the Timing Boost settings have been made correctly.

Below are the starting point settings I recommend for someone first using an RS with a 10.5 motor in 12th scale using a 1S LiPo. These should be regarded as a baseline and are a little conservative. Additional tuning should be performed according to the motor used, driving style and track size and layout in order to get the best out of the RS. The motor settings shown are for a Tekin Redline 10.5.

Motor Timing: 0 degrees
Rollout: 61mm per rev (subtract about 10mm per rev for NiMh)
Drag Brake: 5
Reverse Strength: Off
Brake Strength: 96
Neutral Width: 5
Motor Type: BL-FW
Throttle Profile: 3
Voltage Cutoff: 0
Push Control: Off
Timing Boost: 40
Turbo Boost: 0
Reverse Motor: Off
1S LiPo: On
Turbo Delay: n/a
Sensored: On
End RPM: 10516
Start RPM: 1587
Turbo Rap: n/a

For people who want to know more about the Tekin RS and it’s settings in detail Mark Brown has written a very detailed article which is available at http://rcfaq.weebly.com/tekin-rs–hotwire.html.

Thanks to Tekin team manager Randy Pike for help and advice while writing this article.