H2-CTRIO memory map in ERM/EBC100 configuration

[keith]

I am wanting to  multiple H2-CTRIO2's in a system, with a H2-EBC/ERM100 expansion network.  I would like to improve my scan rate of the remote I/O.  It maps  6 words of discrete inputs, 6 words of discrete outputs, 16 words of analog inputs, and 20 words of analog outputs.

According to the H2-ERM manual, it takes 1 PLC scan for every 64 words of a given data pool (din, dout, ain, aout).  Looks like I could easily exceed the 64 word limit on all the data pools.  It might take 8 PLC scans to do a complete update.

The CTRIO seems to wastefully map stuff I am not using.  If I had more control over the memory map it would be more useful.  On some of the CTRIO modules, I only need to read a double word from each quadrature axis.

Is there any way to limit the memory map of the H2-CTRIO when not using all the features ?
It would also be nice if you could map the din/dout with the analog in/analog out, similar to a configuration I used when hosting the card in a CPU base rather than in an expansion base.

Are there any options which I am not aware of to improve the situation ?
If I could just map the 16 analog input words, and none of the other stuff, that might be sufficient on some of the cards.

Can a ERM100 really only transfer 64 words per PLC scan ?  Is there no way to give it 2 time slots per scan (other than adding a second ERM100 card to the base) ?



Keith

[franji1]

The ERM is a slave to the CPU, so the CPU controls the transfer rate and amount, not the ERM.  The 260 can support up to 4 transactions of 128 bytes per scan, but the 260 firmware throttles it back based on various factors (Koyo wrote the firmware, so we do not know any details).

The best option to fix your situation is to upgrade your PLC to using Do-more CPUs.  If you get one with the Ethernet port, you don't even need an ERM module.  The built-in Ethernet port supports Ethernet I/O NATIVELY (think EM/CM, but using very fast Ethernet with very fast CPUs on both ends).

The 2x0 205 CPUs are old technologically.  They are limited in memory and size, relative to a Do-more.

BTW, we have had customers purchase multiple ECOMs (and similarly ERMs) to double or even triple their data rates with the older 205 CPUs.  I don't recommend that - but definitely look at moving to Do-more for tons of other reasons, not just this one.