external I/O

[machinemaker 0]

I am sorta new to Allen Bradley. I want to connect external I/O to a 1761-net-eni. I did configure it. I want to add I/O over the ethernet. I am using the MicroLogix 1400. I know there is a ethernet port already on the 1400 but want to separate the I/O from the HMI which is communicating on the 1400 built in port. This is more of an excersice to work with the ethernet. I have the Automation Direct Terminator I/O. Even if I connect the Terminator I/O to the built in port, how do I configure the 1400 to communicate to the external I/O? Is there documentation? The manual for the ENI is not very helpful. I am seeing AB documentation is poor at best. I had to download many manuals just to do some simple tasks. Is this normal?

[b_carlton 61]

You have chosen a very strange way to try this. If I really wanted more I/O for the 1400 and had to use Terminator I/O I would use the serial port as RS485 (with the 1763-NC01 breakout) to a T1K-Modbus communication interface. Then I would use Modbus MSG commands for transferring information. There is no common Ethernet protocol between the Terminator I/O and the NET-ENI/1400. Since the MicroLogix 1400 doesn't normally take remote I/O it's no wonder you are having difficulty finding manuals about it. Edited 17 Jul 2012 by b_carlton

[machinemaker 0]

Adding I/O is so much easier with Automation Direct. I was just trying to add more I/O to the system to parts of the machine that are a little far away. There are 8 pieces of equipment that make up the total working machine. I might just add plcs to the others and make them stand alone. All each one needs to see if there is product there and do their thing, then pass it along. This is all rework. Originally they had one plc in the main cabinet and ran lots and lots of wires to each. The contactors were also in the main cabinet. Also I was just testing how hard it was to add I/O using ethernet. Thanks for the info.

[Shiner 2]

AD has its way, as do others. Eaton has developed remote I/O that is made to connect to AB processors, so you can increase your I/O count without running up a major bill. Just an FYI if you are looking for a pre-designed cost-effective solution.

[machinemaker 0]

still bothers me why would AB make an ENI device connect serial to a plc then out to Ethernet instead of making an ethernet module that plugs onto the bus like other I/O cards. Then be able to communicate native or modbus to ethernet devices?

[alan_505 24]

in the AB world if you want Ethernet I/O, you need to use ControlLogix or CompactLogix, there are good small versions of the CompactLogix line that uses 1734 PointIO for it's I/O so that would be a good way to go if you wanted to have remote I/O on an AB system. The MicroLogix range of PLC's do not lend themselves to networked IO except by using messsage's which can be very messy, the only exception to this is the ML1500 where you can install a 1769-SDN DeviceNet scanner card and use DeviceNet I/O Alan

[machinemaker 0]

Thanks, that is a very good explanation.

[firejo 0]

There are a couple of companies that make solutions to either extend or remotely locate I/O. I like the FreeWave solutions. They are Modbus RTU devices and can be done wirelessly or via a direct serial connection and operate via RS232 (or RS485).