Setting AI/AO Range and Bits on F2-8AD4DA-2

[joem]

Hi,

I have an H2-EBC100 and am communicating with F2-8AD4DA-2 analog modules via Modbus-TCP.  I can read and write the inputs and outputs just fine.  But I'm having trouble setting the input and output ranges, formats, and bit-widths.

I've attached the manual for the module.  It mentions EBC100 a few times, but mostly refer to D2-250 (and other) PLCs.  So I believe I may be encountering a memory translation error.  The manual lists 'V-memory' locations (I'm not sure what the 'V' refers to), but when I look up those addresses in the HoldingRegister they are blank.

Any ideas?  Thanks.

-Joe

[Greg]

If you look at your H2-EBC100 in NetEdit and right-click on it and choose Show Base Contents, the Modbus TCP mapping is revealed. An example pic is attached which shows the F2-8AD4DA-2 module in Slot 1 of an H2-EBC100 base. Notice the addressing is:

8 - Word inputs (Input Registers 30003-30010)
8 - Word outputs (Holding Registers 40001-40008)

The 8 Word Inputs are the 8AD part of the module.
The first 4 Word Outputs are the 4DA part of the module.
The last 4 Word Outputs are for configuring the module. In this case:
40001 - Output 1
40002 - Output 2
40003 - Output 3
40004 - Output 4
40005 - Input Resolution
40006 - Range Selection
40007 - Track & Hold
40008 - (not used)

[joem]

Thanks.  That's exactly what I was looking for.

Follow-up:  Assuming that I don't look to change the input resolution, range selection, or T&H, is there a delay incurred if I write to all 8 registers (as opposed to just the 4 analog output registers)?  Thanks.

-Joe

[Greg]

If by "delay" you mean does it take longer for the H2-EBC100 to write to more analog outputs across his backplane for a given module, yes, it could, but in most cases this is negligible. If you want the gory details please study the very detailed EBC FAQ0017.

I would advise you to go ahead and write all 8 outputs all the time. In this manner, if that H2-EBC100 happened to lose power and disappear for some reason, then as soon as it comes back online, it gets immediately reconfigured properly by the master.