You created a new topic for integrating with codesys but this page is said private…
So I post my next question here.
Codesys when reading modbus register is reading words but VAR of the controller use 2 words for each tag. What is the format used? IEEE? How can I decode?
For PT1000 input, the format seems to be integer with a multiplier of 0,1.
So if I want to code in Control basic filter a temperature at long term ( 2 hours) with a first order lag function, do I need first to convert pt1000 integer value to real of is it transparent for user?
Code example welcome
I should receive my Nano and PT12 this evening…
I would like to have setpoint, raw measure, filtered measure all in the same format …
My idea is to store filtered value in VAR . Do I need to store also measurement to have the in the same format for modbus reading?
First trial with T3-Nano and PT12
So delivery was ok and the module are now connected on my desk for a first trial…
I connected nano on my network and made a discovery with empty list as a result but finally the Nano appeared in the local network and took an address from DHCP
Then I connected PT12 on the main RS485 and PT12 appeared automatically in the expansion io and in the tree , great!
The measurement on pt1000 was wrong in the beginning.2wires… I didn’t remember where to find the cabling instructions. After connected jump wire, the measurement was ok.
But the range column keeps wrong and signal type also as you can see from the picture
I also noticed that the out of range value has the priority over manual mode when status is open
Codesys: I am not much help with Codesys questions but I assume you are using Modbus so the register list may have some clues, access it from T3000 → Modbus Register Viewer.
Pt1000: I see you managed to set it up as expansion IO, good news.
Will ask the team to duplicate the range setting issue and report back shortly.
Some general info about setting up expansion modules:
You can refer to expansion points in the T3000 environment by referring to the ‘instrinsic’ naming convention of IN1, IN2 and so on. In the codesys environment, if it can talk bacnet that would be your best bet, you can refer to the Bacnet objects as AI1, AI2 and so on. You may have to divide by ten to get DegC, not sure off hand but some of our products do have a multiplier.
Codesys has also the capability of bacnet protocol but this add on is quite more expansive ( 300€) while modbus is already include in the Raspberry controller platform .
This is why I finally plan to use modbus rather than bacnet.
Same for OpenHab and nodered … Modbus is simpler but more popular.
I have seen that modbus pool register have some option for display real values also but these were greyed… I don’t know why ?
When using the modbus poll register on the subnet ID of the PT12, I could see an integer value with a 0.001 multiplier ( 33354 stands for 33.35 degC)
I finally could see the same in the network variable display inside the T3000 software.
Up to now I could not find the VAR format of the controller. I only know that it uses 2 words. So perhaps it could be a long integer like the input with a 0.001 multiplier…rather than IEEE float format.
This should be clearly mentioned in the documentation …
Another question is about the wiring of PT12.
Documentation says that thermistor can also be connected but the only wiring doc was displayed in the store website… and mention only pt100 and pt1000 cabling.
The terminal label on the doc and on the PT12 are not the same… especially for the 3 terminal output.
Where can I find a pdf doc for PT12 like the one I did download for the Air quality module? Same question for the nano.
VAR format: I will need a little clarification what you are referring to there, but in general you can refer to a VAR in your program like this:
10 VAR1 = VAR1 + 1
To read it in Bacnet you refer from your external master controller to AV1
And to read it in modbus, well you need to dig through the modbus register list which last I looked was over 1400 registers. Its easier to search using the spreadsheet version:
Pt wiring: I have asked our team to show how they wire 1k Pt and will post a photo shortly. Should be in the documentation as well, two wire, three wire and four wire connections are supported. For two wire connections you need a couple little jumpers.
Sorry @maurice, my question was not clear.
When opening the spreadsheet referred in your post I found something similar to the access file that Is in the t3000 software distribution.
But there is another excel file with additional information and a little different presentation in the t3000 directory .
Anyway none of these file contains any explanation about the coding format of a VAR in two words of 16 bits.
This is my question … var are displayed in the software in a real format like this 33.345.
Is this a real floating format ( meaning that calculation are done with the related precision of floating calculation or is it a double integer format with 3 decimal digit format meaning that all real calculations are rounded with this precision?
In other words , am I able to preset a Var or calculate a real value like 0.00000345?
Regarding the wiring of PT12 , my question is more how to connect other type than pt100 and pt1000 of 2 wire thermistors ( do I need jumper in any case?)
Byte format: I will ask one engineer to reply and also to improve our documentation in the next release.
Pt1000/100: These sensors come in two, three and four wire configurations because you need to cancel out the cable resistance as you know. In two wire configuration you just need two wires, I think the documentation has a wiring diagram for these things.