Retention options for MFD

[Neil]

The available options for setting retentive data range appear to have a serious limitation. You can only select marker bytes (1-96) and no access to upper memory areas MW,MD etc. which severely limits applications handling recipes (such as mine)

I have 10 recipes each with 8 byte parameters requiring 80 bytes of retentive data. Unfortunately I also need more MBs for other tasks so I keep my recipes in upper MDs leaving the MB1-96 free for other things and do Block Transfers to shuffle the recipe data around. However this data will of course be lost on power-off!!!

Is the retentive data options a limitation of the hardware itself or is it just an oversight in software, i.e. would it be possible to select MW or MD as part of the retentive range?

[julian]

Neil,
why don't you use twenty retentive data blocks DB?
If this is not possible add a EASY-800 without display and store/receive data with put/get commands via EASY-Net in it.
I think the retentive data range is limited by hardware und not expandable.
If you need detailed informations contact
mfd-titan@moeller.net
Regards,
julian

[Neil]

Hi Julian,

Thanks again for your help. I am a little confused with the DB functionality. As I understand it a DB is used to move a piece of data from one place to another, i.e. from an analog input to an MD etc. I see that you can make DBs retentive so if I move an MD into a DB, and then power-cycle, the result of the DB will be retentive so all I need to do is move the DB back into an MD and then all is well? With me so far...

The best function to move a piece of data is a DB of course so we need 20 DBs to move 80 bytes of data (20 x 4 bytes), but then of course we need another 20 DBs to move the data back into the MDs!!!!! Guess how many DBs we have?? 

This is all getting rather messy and what is needed of course is indexed rather than absolute addressing so that we can set-up pointers with DBs but I can't see a way of doing this?

With respect to your alternative suggestion to using PUT/GET is there an example available?

I will forward my application to Moeller support but as yet my emails have gone unanswered.

Thanks again,

Neil

[julian]

Neil,
of course if your program takes 20 DB's then the 12 remaining can't store the 10 recipes.
I created a put/get example for one recipe (2 retentiveDB).
The extension NT2( EASY-800) can be replaced by a MFD-CP8-NT module.
For short distances NET baud rate maybe increased to 1Mbaud.
M01 stores values to EASY 800.
M02 recalls values from EASY 800.
This example was tested with real hardware by me.
Please see the attachement.
Regards,
Julian

[Marty]

I need to use some retentive MW's (or DB's).  I seem to have trouble grasping the general concept.  Some questions:

Can I initialize an MW and let the operator change it?  If the system is powered off/on, I don't want the initial value to be reinitialized. 

Or do I have to start with any retentive valves at zero?

If I use a retentive DB, do I leave the input blank? Are there any quirks in wiring it?

Does the retention work with simulation (i.e. stop and restart simulator and retentive value is kept)?

Thanks,

 Marty