CH 0 as DF1 Half Duplex Master

When setting up Channel 0 of a SLC 5/05 as DF1 Half Duplex Master, I choose Std. multiple msgs per scan for polling mode. This choice makes Polling Ranges choices visible in the dialog box. There is no help or narrative on what the choices mean. The choices are:
Priority High
Priority Low
Normal High
Normal Low
Normal Poll Group Size.
My questions are:
1. What is meant by high and low? Do they mean node or addresses?
2. The default Group Size is 0. Must it be greater than 0?

Application: I have two power monitor 3000s connected 485 into a 1761-NET-AIC and then DF1 into port 0 of the SLC. My message statements are timing out. Error 37H - Message times out at local processor. The TX lights on the NET-AIC are all flashing green so I assume things are good up to that point.

Application: I have two power monitor 3000s connected 485 into a 1761-NET-AIC and then DF1 into port 0 of the SLC. My message statements are timing out. Error 37H - Message times out at local processor. The TX lights on the NET-AIC are all flashing green so I assume things are good up to that point.

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Whats the protocol of the power monitor? The AIC+ is not a protocol converter.

Because the PowerMonitor 3000 devices are pure DF1 Half Duplex slaves, you should use the Poll Mode = "Msg, Don't allow slaves to initiate".

When you use Standard Polling Mode, this automatically sends out "poll" frames that allow DF1 slaves to respond with messages that they initiate. The Poll Lists are node numbers, and the Poll Groups are a foreground/background priority mechanism. Interesting stuff, but not applicable here.

The LEDs on a 1761-NET-AIC flash when the port transmits, but not when it receives, so flashing lights don't prove anything by themselves. With any RS-485 system, I always try swapping Data A and Data B as a diagnostic measure.

There should be a Knowledgebase document or something in the user manual regarding the configuration of a Net-AIC and MSG instructions to the PowerMonitors. I haven't done this in a couple of years, but I recall that the hardest part was getting the DF1 Node Number correct in the PM3000; it defaults to a seemingly random value that is on the label and easy to access with the menu, but is not "1".

There is an SLC Channel 0 port configuration and MSG instruction example in the PowerMonitor 3000 User Manual starting on page C-2.

One thing that stands out in the Channel 0 configuration is that the Pre-Transmit Delay is set to 20 milliseconds.

The example destination DF1 Slave node number in the user manual is "114"; the factory-set node number should be on the label on the side of the PowerMonitor and should also be available from the Display Module in the PROGRAM > NATIVE COMMUNICATIONS menu. This is described on page 4-2 of the User Manual.

My user manual dates from 2003, and I see from the Literature website that there has been a relatively recent version 3.0 upgrade to the PowerMonitor 3000 with a corresponding new user manual. The DF1 Slave native communications should be the same, but of course you're going to want to get the User Manual for the devices you have. Do a search on 1404-UM001 on the RA Literature website.