Micrologix 1100 vs 1200 scan times

Hi guys,

I have several machines that are using the Micrologix 1200 with a Panelview 300 HMI which I would like to convert to a Micrologix 1100. The PLC only has one available mini din port for DF1 to the HMI. If the HMI is connected to the PLC com port, there is no programming port available unless you disconnect the HMI. And no port for data acquisition if required (unless you use a port splitter or expansion card). To overcome this problem , the Micrologix 1200 goes to a Net-ENI and the Panelview 300 to another Net-ENI and both Net-ENI's to a 4-port ethernet hub. The data acquisition for a future SCADA system can be accomplished through the hub.

Timing of the triggers and delays is very critical with 4-high speed vision cameras checking for different profiles and 1-laser sensor checking for threads on nuts situated on a circular high density dial which must must put out 300+ nuts per minute (target is 500+ nuts per minute) and must detect 99% reject parts.

I checked the scan time of the Micro1200 with the running program and read 12ms peak. With the same program on the Micro1100, the scan time read 90ms peak. I called Rockwell and they informed me that the e-net port on the 1100 requires a lot of overhead and therefore will slow down the scan time.

Has anyone else come across this problem?
Any suggestions or ideas are much appreciated.

Thanks in advance,

Tam Ho

Wow, it looks like the micrologix may not be up to the task. 90ms is ridiculous. My red flag goes up when I see any PLC/Program running slower than 20ms.

Have you looked at Compactlogix or Contrologix? I think you can get the speed and comms you need there, but my experience is limited.

Another option is go to the Micrologix 1200R which has two serial ports. For Micrologix apps thats what I use anymore; no more monkeying around with disconnecting the HMI to get online.

Hey guys,

Thanks for your help and sorry for the late reply.
I tried posting a response over the weekend but my internet crapped out and when I hit the back button, all my text was gone and could not retrieve it.

OkiePC:
I have looked into the compact/control logix, they would most likely offer faster scan times but at higher costs and all machines would have to be reconverted to RSLogix 5000.

jstolaruk:
The Micro 1200R looks great, one port to panelview and the other for programming or to a single Net-eni for data acquisition. At least it gets rid of one expensive net-eni module.

Thanks guys!