I am trying to establish a fast communication to monitor and control a Seimens TI545 PLC (model 545-1106) with the Maple Systems HMI5104X interface. Earlier systems I set up were with the HMI550T, which is no longer available. With that earlier system, I had no problem with a fast communication link.

With the HMI5104X interface, I can't get fast, or even reasonable, communication with the TI545. I've tried many different wiring schemes and COM ports. I've used RS-232 and RS-485 protocols. No matter how I've been able to get communication, it has always been at turtle pace. Also, if I place more than 16 I/O points on a single page, data becomes garbled and errant.

Then, with the same PLC program, I connect an older HMI550T interface and, PRESTO, the communication is perfect.

I need any help available. Thanks,