Controlling a Load Drive using Modbus TCP or Ethernet IP

Hello,
My name is Francisco Loras. My team and I are looking forward to building a dynamometer in order to obtain test standards for motors. We're going to use a Load Drive in order to control the Load Motor. The Drives we have been looking at are either from ABB or from Yoskawa (a1000), both offer the option of connecting via Modbus TCP/IP or via Ethernet IP. I was wondering if someone has previously worked with them and could give me some feedback on either the drive or connection type. I would preferrably use Ethernet because the complete system we're building requires at least one more ethernet connection (for a Power Analyzer).
Besides this, we were counting on using a Chassis from NI to put everything together. When looking at the specific modules, we considered two options:
1- Using an ethernet module (from NI that fits in the Chassis) to drive in both the Power Analyzer and the Load Drive.
2- Using an ethernet switch setting specific IP addresses.
Has someone used any of these before? A switch would be close to 50 times cheaper than using the ethernet module itself so I'm a bit worried there might be something that limits it or that I'm missing (noise maybe?).
To conclude, I'm looking forward to se if someone has:
1) Used Ethernet IP or Modbus TCP/IP to control a Load Drive, which connection type is best if any.
2) Recommended any specific load drive
3) Experience with using an ethernet switch or an ethernet module.
Thankyou very much for your help and time,
Francisco
PD. If something is unclear (which I sense it is) please ask me and I can develop more on it.

Florasga,
Which ethernet module are you looking at? And what kind of chassis are you planning on using?
There's some more information on Modbus here. Also, have you seen this forum post?
Kyle T.
Applications Engineering
National Instruments

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Attachments:
modified code.png ‏18 KB
Original code.png ‏15 KB

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