Spotty Communication between an AB SLC 5/05 & a Red Lion G315 HMI

Several months back we installed a Red Lion G315 HMI to communicate with a AB SLC 5/03 attached to the ethernet network via an AB ENI module, using DF1 Master via PCCC/EIP. To date, communication has been fine, until:

We installed a second G315, nearly an exact copy program wise to the same network. These are at our inspection/grading station, not that that is important to you, but that is their general purpose. While both G315's connect and communicate, they appear to lose communication every 10 - 15 seconds or so (data disappears and is replaced with dashes), and then reconnect a couple seconds later (numbers return). They appear to do this in tandem (both at the same time). This is our protocol setup in the G315's:

Enable Device: Yes
Device: ENI/Micrologix
IP Address: 100.100.100.11
Slot Number: 0
Transaction Timeout: 1000 ms
Spanning Reads: Enabled
Transactional Reads: Enabled
Preempt Other Devices: No
Favor UI Writes: No
Comms Delay: 0 ms

Do my settings appear correct? or am I missing something? I do plan on replacing the 5/03 with a 5/05 during the next shutdown weekend, but considering that these G315's replaced two Panelview 1400's that were communicating with the same processor on serial/DH485 with no problems, I have a feeling that the processor change will not correct this problem.....

It's likely the connection limit of the Net-Eni. Use a browser to check.

I would approach this as a serial bandwidth issue, despite the previous communication method's success.

The Net-ENI has to translate every Ethernet command to DF1 and translate the reply. The effective bandwidth is equivalent to maybe a single 9600 baud link.

I'm not a Red Lion driver expert, but I would recommend adding a "comms delay" to slow down the requests from the two G3 terminals.

I agree that you most likely are limited by the serial speed of the Net-ENI. This would explain why it would work fine with 1 HMI, but when you installed the 2nd one (which doubled the total amount of connections), it gets flaky.

IMO, installing a 5/05 would be the best way to solve the problem. Hopefully you can hop along until then.

Replaced the 5/03 with a 5/05. Life is good now.....

Good to hear that