Mitsubishi FX - or maybe Omron. Naah, definitely Mitsubishi.
Mitsubishi again - assuming you don't want comms. If you do, then either AB
CompactLogix or Schneider Momentum depending upon exactly what comms.
Siemens S7-300 by a long way.
Probably AB ControlLogix by a small margin from Siemens, Schneider/Modicon
et al - depending upon what you need to do (motion control? process
control??) and what you want to talk to (Profibus? DNet??)
You might like to expand on your requirements a bit. eg. if you need CPU or
PS redundancy, then the race is completely different.
A-B MicroLogix is a good choice if you only need serial communications
in an RTU or stand-alone system. For one client, I just received the parts
to replace an ML1500 with an SLC-5/04 so that we can get this last panel
onto the DH+ network and the program into Cimplicity Manager.
Momentum offers Ethernet processors and Modbus Plus options modules.
On my last big project for my previous employer, each of the 10 filters had
a Momentum with MB+ for the network, Modbus RTU from the RS-232
port to the Exor HMI, and Modbus RTU from the RS-485 port to the 7
valves. Next time, I'd recommend an all-Ethernet solution for the HMI and
network to the consulting Engineer.
Mike, I must admit that I haven't had a great deal of exposure to the
Momentum system and most of that was heresay, but we have tendered for a
large project with an existing Momentum network on MB+ and are thinking of
using some of the Momentum gear as remote I/O drops (including some remote
Modbus RTU comms) back to a TSX Quantum PLC system and Ethernet SCADA.
In your experience, what was it like to set up? Pretty straightforward or a
right pain in the ass??
I did one job with Compact 984's and MB+ distributed I/O to Momentum
bases in the remote panels. Each base had an MB+ communications adapter
using one node on the network. In Modsoft, I configured the Peer Cop for
each node, using 00001, 10001, 40001 or 30001 as the starting memory
address, depending on the base type. It worked on the second try and has
been running for about five years now. With a Quantum, you'd have to do
the same thing since the Modbus Plus NOMs only support Quantum
distributed I/O. You can also leave the existing Momentum CPU's in place
for I/O management, move the existing logic to your new PLC and use the
Peer Cop or the MSTR function to move I/O data over the network. It
depends on how you trade off new hardware vs supporting multiple PLC
The answer to that is a big "it depends." Converting the processor base
to an I/O drop is just a matter of replacing the processor and option
adapters with the comm adapter set to the desired node address and
plugging the MB+ cable back in. If you have expansion I/O (Interbus
S as I recall), that means adding a MB+ connection for each base.
I prefer the T-connector kit and drop cable to the inline connector,
unless you're truly close on total cable length. If most of your panels
have multiple bases, you might as well convert to Ethernet with a
dual Cat 5 home run (1 spare) and an industrial hub in each panel.
In a new installation, I'd recommend Ethernet. There's more initial
configuration involved, but you have all home runs instead of a
network layout. Plus, I think there are now more installers who know
how to terminate and test Cat 5 than MB+. I really don't want to
repeat the job where half the inline connectors were ruined or the
other where they broke the tee connectors by punching down 16
AWG instead of the specified 22 AWG cable.
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