Operating the Jrk12v12 at Analog voltage mode


My name is Sergei, I work with Jrk 12V12 and linear actuator (LACT2P).

I need to control the actuator (througth the jrk) by analog voltage. In order to perform it I have connected the potentiometer to the appropriate connectors of jrk (pololu.com/catalog/product/1394 - the link where you can see how exactly I’ve connected the potentiometer) connected the actuator and it’s feedback in proper way, choused the mode "Analog Voltage in the Jrk utility ( utility works under the tools file for linear actuators, downloaded from your site, the only thing I change it is the mode, I change it from serial to analog, all other tools remain the same), and clicked "apply the settings to device. After these actions, the actuator gets the target that shown at the utility interface, and I can’t manipulate it with potentiometer (actuator simply not react to it, although there is changes in voltage on potentiometer).

I have checked all connections for the wholeness, the supplied power is ok ( I can munipulate the motor manualy in serial mode througth the utility).

I think, I just havn’t checked some checkbox or something like that, because the text file with settings from your site, that I load in the utility, wrote for serial mode. Please, can you describe what exactly all the actions and their proper order I should to perform to get controled my actuator.

Thank you ahead for you help,

P.S: Yesterday I have contacted you by e-mail, so avoid answering twise.

Hello, Sergei,

I am sorry you are having trouble with your jrk and linear actuator. Have you also connected the feedback wires from the actuator to the appropriate pins on the jrk? The product page for the actuator contains details on how to do so, in the section “Using a jrk motor controller with a linear actuator with feedback” near the bottom. (The picture there shows a jrk 21v3, but the connections on the 12v12 should be similar.)

Could you please describe all of the connections you have made to the jrk? It would be helpful if you could post a diagram or picture of your entire setup.

If you are unsure about your settings on the jrk, you can also save those settings in a file (“Save settings file…” from the File menu in the Jrk Configuration Utility) and post it here.

- Kevin

Thank you for answer, Kevin,

Here are all connections I’ve made: Connections.pdf (468 KB),
and here the settings file I’ve saved, as you asked:Settings_file - Notepad.pdf (16.7 KB).

Thanks a lot,

Hello, Sergei.

If you successfully set the Input Mode to Analog, I would expect the jrk’s Input variable (which you can see in the plots window) to reflect the voltage on the RX line. If you move the potentiometer from one extreme to the other, you should see the Input go from around 0 (0 V) to around 4095 (5 V). The Target variable is calculated by applying the Input Scaling settings to the Input. With your settings, it should go from around 0 to 1000 as you turn your potentiometer from one extreme to another.

Is this what you are seeing when you look at Input and Target and turn the potentiometer? If not, what values are you seeing for the Input and Target variables? How are you measuring the changes in voltage on the potentiometer, and what voltage values did you measure?


Hello David,

In the plots window I see turquoise line that is constant at 100% and does not change it’s value during voltage changes. If I move the potentiometer from one extreme to the other I measure (with multimeter) voltage in range of 0-5V, but the target value on the screen of utility remains the same (and input line in the plots window too) that I’ve set before clicking “Apply settings on the device”.


I checked your settings and they seem reasonable. Have you made sure to actually write them to the jrk with the “Apply settings to device” button in the lower right? I noticed you said “I can munipulate the motor manualy in serial mode througth the utility” in your first post, but you should not be able to use the slider to manually set the target if the jrk is using its analog voltage input mode.

By the way, I just enabled the attachment of .txt files to forum posts, so you should be able to upload settings files in the future without converting them to a different format.

- Kevin

Yes, I’ve write the settings of analog mode to the device. Manual manipulations with a slide bar were done before applying settings of analog input mode. After I apply the analog mode settings, actuator gets the target (that in the check box of analog input mode interface) and I can’t use the slider bar ( it’s transparent).

The all connections seems ok, I’ve checked them many times, I thought the reason is not appropriate settings, but if you said that there isn’t problems in settings file, may be the problem is in device itself? How can I check it?


It sounds like the input pin on your Jrk might be defective. I will contact you via email regarding a replacement.

- Kevin