Need advice on which solution to go for (Omron or Panasonic).

Hello All,

I need help in evaluating the viability of the proposed solution in terms of ... lag between the PLC and linear drive that I will be using. Thing is, linear drive controller does not support modbus tcp (only profibus dp or ethernet ip) so I have to connect it via remote PLC that is in the loop. Issue that I am seeing with this is that it creates too many points (and bottlenecks) of failure.

The system overall will have local ~150 DI's, ~70 DO's and remote ~70DI's ~50 DO's, plus a handful of Analog IO's for each.

So the pick that I am currently looking at is by Panasonic:

PLC: Panasonic FP7 with Modbus/TCP (Modbus TCP Link Master. Connects with FPWEB2)
+ IO's

FPWEB2 (for modbus TCP slave connection with FP7 PLC, Serial connection with FOG-C32T PLC)

Remote PLC: Panasonic FP Sigma PLC with COM4 serial card
+ PROFIBUS Master
+ IO's

Possible timings (milliseconds)
Scan time FP7 - at 11ns per step with ~ 40k stem program - 0.44ms
Data time to FPWEB2 - not sure.. depends on data length
FPWEB2 response to serial - few milliseconds
Serial data transmission time to FP Sigma - not sure, but considering high baud rate shouldnt be too high
Scan time of FP Sigma – FP Sigma is slower with a scan time per basic step at 0.32µs. ~ 4k stem program 1.28ms. I could use interrupts to reduce this.
Response of Profibus unit – min scan time of unit = 350µs
Profibus transmission to linear drive controler – max 12Mbaud (cable length is ~30 meters)

Thing is that with so many different comms the timings not only for the linear drives but for remote IOs could be a bit off..

Other possibility is Omron CJ2M PLC with Ethernet IP that can connect to linear drive

I have used both Omron and Panasonic before and if it wasn't for the superior support, programming environment preference (by a lot...) and cost for the proposal (~20% cheaper for Panasonic), I would go for Omron.

Am I over analysing things here or should I go for Panasonic and not worry about any of this?

everything have advantage and disadvantage,

i will prefer OMRON

Usually, total latency isn't the issue; having a 10ms delay every time can be accounted for. It's the jitter you need to worry about. Since your actuator only supports non-deterministic protocols, you're going to have a few ms of jitter no matter what. Your biggest source of jitter is usually how frequently your logic is scanned; if the input turns on just after the line it is scanned, it must wait until the next scan, just before and it doesn't wait.

If you're looking for reaction time on the cheap and protocol support, B&R has the edge over both your listed options. For around the same price as the Omron, you would be looking at 400µs cycle times on a deterministic protocol to a PROFIBUS DP V1 master interface. Of course, the profibus between the interface and the actuator still won't be deterministic; if the linear actuator supports ProfiNet or Powerlink, that would be much better. Even with profibus, you could get the time from output needing to be sent to output transmitting over profibus in under 2ms easily and with a little tinkering with timing optimizations it could be under 1.5ms.