I want to get the maximum out of this little HMI, and I am trying to configure a Real Time Trend object.
When using a fixed time span in seconds and fixed lower and upper limits it works ok.
But I want the user to set the trend resolution by adjusting the trend time span between 1-120 minutes and the value scale lower and upper limit between 2.0 and 20.0ºC.

So, I have made 3 entries for these values:

Trend time span - data entry object configured for register tag D52, data type BCD, format ####,low/high limit set to 1/120. In the PLC I multiply this value by 60 and write the result to D53 (+D54).
Trend lower limit - data entry object configured for register tag D54 D55, data type BCD, format ##.#,low/high limit set to 20/200.
Trend upper limit - data entry object configured for register tag D55 D56, data type BCD, format ##.#,low/high limit set to 20/200.




Here's the trend screen:



I have configured the trend object as follows:











A few questions.

1. In the help/manual it says up to 4 tags can be displayed. Why is this setting fixed at 1 ? I can't seem to change it.

2. When viewing the trend on the NT3 when online with the PLC, it gives me a "invalid limits for Y axis" error.
Also, the value scale tags and the time scale tags do not show, which they do when selecting a fixed scale limit and time span.
If I check the values of the tags in the PLC they contain valid BCD values, the lower limit value is less than the upper limit value, and the value of the tag to be plotted lies between these two.

3. Could this have to do with the fact that I have configured the comms driver for Host Link CPM2 while I am testing with a CJ1M ?

Can't find any hint in the manual/help file what I am doing wrong.
Any ideas ?

The only thing I can see so far is that the numeric entries for lower and upper limits were set to D54 and D55 but in the trend setup you are using D55 and D56. D54 is conflicting because it will contain the high byte for the Trend time span result of D52*60 stored in D53 and D54.

Thanks ECSI, very sharp but that was a typo. I actually use D55 and D56 at the numeric entries for lower/upper limit.

Hi Pdl,

Number of trends is fixed to 1 ( manual error)

Have you tried the same with integer values instead of BCD?

regards,

MPM

Yes, same result.
Anyway you can check now you have the project !?