Editing memory using the Data View edit feature.

[8bits]

I notice that when using the Data View window and editing an address in the V7400 range , that any edits
to a memory location in that range changes the non volatile location as well. Usually the edits are for RAM V memory and writing to NV memory is somewhat unexpected. The way I verified this is by having several rungs that restored other V memory locations (not in the V74xx range) when executing a PLC reset..
This seems different from the documentation that indicates that the ONLY way to write to NV memory is to use  the MOV instruction.  But, there is also a V7400 that is NOT NV memory. So, how can using the Data View edit mode write to the V7400 area that is NOT non volatile memory?

This is something that needs to be clarified.
As a suggestion, I would have it write only to regular v memory and not NV memory. Or better yet, how about a distinction and a choice of writing to either of the two different memories.

[b_carlton]

You didn't mention the specific CPU. I looked in the manual for the DL06. Its diagram shows very specifically that Directsoft writes to both the RAM and to the Flash ROM.

[MikeS]

i think the issue is the protocol of the DirectSOFT link you're using.

A link using KSequence protocol will write to both locations, but a link using DirectNET protocol will only write to the RAM locations, not the NV locations.

(I may have that backwards, but one protocol writes both and the other writes only to one).

[8bits]

Read my post, this is not about the protocol but about using the DirectSoft5 data View and editing in Data view a memory location in the range of V7400 and above. Which the documentation (DL05) identified as having both a RAM address as well as a companion address located in the Non volatile memory area. This area, NV memory, of memory can only be written to using the MOV instruction(?). Apparently this not the case when editing in Data View.

However, when using the Data View edit mode as described above, it changes the non volatile location. This seems in conflict with the idea that using only the MOV instruction will write to the NV memory.

So, the problem is, when using the Data View and editing memory, is it writing to NV memory or to local RAM or both?

I think an improvement would be to allow the Data View edit mode to write to either with a selection to select which one you want to edit.

What is one to do when you only write to local RAM and not to the NV memory address? This is for troubleshooting.

Thanks for your responses.

[Controls Guy]

But Data View and edits in DirectSoft must be done via either the DirectNet or KSequence protocol.  You choose one or the other when you create your comm link in DSLaunch.

[b_carlton]

Mike - do you have any documentation as to a difference in behavior relative to NVRAM when using the different communication protocols? Or is this just by experience?

[MikeS]

Automationdirect.com has this app note: http://support.automationdirect.com/docs/an-misc-026.pdf which talks about these memory locations.

It says the MOVE instruction, HPP, and DirectSOFT can write to both locations. Since the HPP uses K-Sequence protocol, that would mean that a DirectSOFT link configured to use K-Sequence would operate similarily. Which would imply that a DirectSOFT link using DirectNET would only write to the RAM, not to the ROM.

[b_carlton]

Which would imply that a DirectSOFT link using DirectNET would only write to the RAM, not to the ROM.

I don't get that implication at all. It says nothing about DirectNet NOT doing the same thing. It says nothing about differences in communication protocol.

[franji1]

Someone at ADC or Koyo will have to make an "official" statement, but I'm bettin' that the K-Sequence protocol in the PLC also writes to ROM, but the DirectNET protcol in the PLC does not.  There is no comm function that distinguishes the destination of a write to V7400.  All DirectSOFT and the Handheld do is send a "write to V7400" command.

[MikeS]

I asked to guys at ADC.com to ammend that PDF to change the reference from "DirectSOFT" to "DirectSOFT using K-Sequence protocol".