I have been working with a trio of Tstat10’s connected via BACNET to the RS485 subnet of a separate T3-Nano for each. I had a test area set up in a workspace with very short communication cables, and had no issues programming these devices. After this, they were powered down until ready for testing with our final product. I have found that in this time period of ~2 weeks without power, the programs seem to have been corrupted. Whenever trying to retrieve the program from the device via T3000, it throws a decode error and either pulls up blank or in a manner that is clearly very corrupted.
I need to understand why this might be occurring as I will have to power these down again during shipping until their install, and I cannot just have the program forget itself every time. Another detail that I noticed is that RS485 communication seems to be extremely weak. I have run these in shielded cable at a baudrate of 9600, which the practical limit for this is 4000 ft., yet I can hardly run the cable 3 feet without significant issues.
Any help would be appreciated. This project has been in limbo due to the controls and I would like to get it out of our shop ASAP.
Losing the programs is rare, we have seen it only a small handful of times. The program is stored in flash memory which is nonvolatile, it will save all the data for many years without power.
There is a cache which is automatically updated as you work on your programs, you search around in the \T3000 installation folder to see what is there, on my system it is under:
C:\Program Files (x86)\T3000\Database\temp\prg_txt_file
Note: these txt files use the user labels in the program so if you named IN1 as OAT, you will need to rename OAT in order for the editor to understand what OAT is.
If you can send any of your old *.prog files perhaps we can spot something.
Final note: As you program you should save your work, do this under T3000 → file → save as. This saves all the inputs, outputs, variables, programs, graphics, alarms and so on into one handy single file which can be used to load into other controllers or for disaster recovery. Make it a habit to save often as you work.
I figured that programs would be stored in non-volatile memory, which makes this problem an even bigger issue since it is replicated on all three devices I have. Trying to reload a corrupted program slot with a fresh program also does not work. After hitting send and receiving a successful compile message, if I try to reopen the program I am met with the same decode error as before. This is an issue as now the device will not accept new programs either.
I do try to regularly save while working, but I have had a degree of unreliability in T3000 where it will just crash upon saving. Not exactly great for if there was a ton of work done. I have attached the latest .prog file I had, along with the two control basic programs I was running. A description of my setup would be as follows:
A T3-Nano with its ethernet side connected to the main network, and its RS485 subnet connected to the Tstat10. Communication is BACNET/MSTP. The Nano runs no programs and functions purely as a gateway. The Tstat10 has its physically available I/O configured for 1 analog input and 3 digital outputs. The analog input is a remote 4-20 mA temperature probe. The read temperature from this is used in the control basic program for temperature control, and also to display that temperature on the screen. The outputs are for compressor 1, blower, and compressor 2.
We have solved this problem today, please upgrade the firmware of T3-nano (Rev 61.0) 。
The reason for this problem is that when data is converted from the network protocol BIP to MSTP, the data length 0x90 and 0x91 needs special processing in the BACNET standard library.
We will Release the firmware tomorrow after a more rigorous test, before which you can download the update through T3000 in the firmware update dialog.
