PS-1-0-0 Random resets while on BACnet

Hello, I’ve got several PS-1-0-0 that seem to be restarting every 10-15 minutes while connected to our bacnet network.

Sometimes they’ll do a full reboot, and sometimes the screen just flickers a few times and the device drops off the network for a few moments, then comes back.

I’m on the same project with jussleman who posted about the damper control. It doesn’t seem to matter if the device is on the version 125 or 126 firmware.

Thanks in advance for your time.

If I understand it correctly you are writing to the outputs of the pressure sensor using bacnet commands on the analog output. Its an interesting project and we’ll get it working for you.

Thank you. What you’ve done for us already is above and beyond. We all really appreciate it over here.

What we’re trying to do is drive a few bypass dampers in a VAV system with no VFD on the supply fan. The rooftop units are older. We’re doing an upgrade on the client’s old control system.

V 126 works exactly as we’d like as far as control goes, but as stated, they seem to drop off the bacnet network at least once every 10-20 minutes.

It may even be an issue on our end? Does anyone have any ideas on how to check that?

So far, we have:

Got a v 125 controller on the bacnet. jussleman found out we couldn’t command the damper directly over bacnet.

We reached out to you guys, you provided us with new firmware, again, thank you. That’s incredible, and isn’t unnoticed.

After installing the updated controller it was noticed that it’d restart every so often. It also seemed to slow down our network. We reversed the polarity of the 24vac, we checked input voltage, we completely disconnected the damper actuator, we swapped out the PS-1 for another updated PS-1, we swapped out the updated PS-1 for a v125 PS-1. Same thing.

I had a couple of them on my desk today for a few hours. One on the rs485 network, and the other not. Neither one was connected to anything else. I don’t think the one that was off of the 485 network had any issues at all. I didn’t see it reboot. The one on the 485 network did.

Baud rates checked. Mac add’s checked. The rest of the network seems stable. These tests are going on in the middle of our daisy chain. Devices after stay online, but overall stability is compromised.

Again, thank you guys/gals. What you’ve already done for us is amazing. We look forward to using your products again on future projects.

Thank you very much for your detailed description and trust in us.

Could you send a wireshark capture file of the BACnet data so that we can better analyze the problem.

Sorry for the delayed response. I had to order a dongle, then learn how to use it. I think I’ve got a couple captures. One without a PS-1-0-0 and another capture with one on the network.

With PS plugged in.pcapng (53.1 KB)

Without PS plugged in.pcapng (54.2 KB)

Thank you for sending the packet capture file. We found some anomalies in it, particularly the large “OUTPUT instance number” values. However, after further research and testing, we have determined that this is not the cause of the periodic restart issue.

I would also like to ask what BACnet software you are using. We are looking to use the same software for our own testing in order to create as similar a communication environment as possible.

We are currently using a standard N4 bacnet driver system connected to Jace units. There are some carrier rooftop systemvue controllers on them. The units stay powered on till we attach the bacnet communication on then they start blanking out the units. Do you think there could be a problem with grounding of the power to your devices. Could this drop out the device power and reset it. Hope that helps.

Unfortunately, we do not have an N4 Bacnet system, and it is difficult to determine if it is a firmware issue based solely on the packet capture files. However, the grounding issue you mentioned has led us to consider a potential hardware-related cause. Could you please test if the PS continues to reset periodically when the BACnet software system is not enabled and there is no Bacnet communication?

The one on the left is on our backnet network, the one on the right is fresh out of the packaging. Still on the Modbus setting.

Lijun will set up a test and report back ASAP.

1 Like

Thanks, again. We really appreciate it.

Is there a way to adjust the output voltage in relation to the pressure?

If I change back Split_IO, it seems that at 0 in/wc it puts out 5vdc, and by .5 in/wc or so it’s putting out 10 vdc.

Is there a way to remap that to something like:

in/WC   VDC
+0.0    0.0
+0.5    5.0
+1.0    10

Maybe something we can adjust onsite, then just run our damper directly from the PS? Then we could just let the PS run independently of the network.

I saw that there’s a calibration table in the t3000 software, but it doesn’t seem to take any changes.

Lijun will check the calibration table, if its there in the UI we should have it working.

You could try a firmware update while you wait, he will be into the office tomorrow.

Regarding the earlier issue with the periodic restart, we’re still investigating the root cause, and we’ll keep you updated as we learn more.

As for your current question about remapping the voltage output relative to pressure—this feature is not supported in the current firmware version. However, it’s a great suggestion, and we’ve added it to our development roadmap for inclusion in a future update.