getting online - half duplex?

I'm helping a field guy to get online with an AB SLC 5/04 at port 0. The program says channel 0 is set to DF1-Half Duplex Master.
Is it possible to go online through this port? What driver should be used in Linx? Do I need a special converter?
Port 0 is currently connected to a power monitor but can be disconnected temporarily.

"RS232 DF1 devices" RSLinx driver, a 1747/1756-CP3 Programmer Cable and either a PC Serial RS232 Port or, if no physical Serial port is available, a quality USB-to-Serial adapter (Keyspan USA-19HS would be my choice).

This is actually harder than it looks.

You could try the DF1 RS-232 Devices driver and select "half-duplex" mode, but I don't think that will work when you are connecting to a Half Duplex Master.

The SLC might be set up for "polling mode", in which case you can run the DF1 Half Duplex Slave driver and set it for the same address as the PowerMonitor that you've unplugged.

But if the SLC is set up for "Message-based communications", it will just send Master messages, rather than Poll commands. And your RSLinx station can't respond to those, since they are intended for the power monitor.

This sort of thing is why all the modern MicroLogix (i.e. every model except the 1000) have a "DCOMM" button to temporarily override the serial port settings and restore the default configuration.

My guy has the Keyspan USB to serial converter which I use all the time plus a 1747-CP3 null modem cable. In Linx He selected RS-232 DF1 devices. For protocool he tried Full Duplex and Half Duplex but still gets the packet timeout error.
Port 0 in the offline program is set as
Driver = DF1 Half Duplex Master
Polling Mode = Msg. Allow Slaves to Initiate
I see in Linx, there is the "DF1 Slave Driver".
Ken, did you mean that one?

Yes, I meant the "DF1 slave driver".

But because the Polling Mode is "MSG, allow slaves to initiate", it may not be possible to go online with the controller.

When the Polling Mode is set for pure "MSG" communications, the Master only sends commands to the slave devices when a MSG instruction is executed.

The "allow slaves to initiate" option means the Master also sends "Poll" packets, to which the slave device can reply with a command to be processed by the master.

When the Polling Mode is set to "Poll", these Poll packets are sent quickly by the master station, and this is how you can "go online" with a controller while being a DF1 Slave station, and how Slave-to-Slave communications and communicate-by-exception messaging is performed in a DF1 half duplex network.

The reason I don't think it is possible to go online with the controller in this "MSG, allow slaves to initiate" mode is that I believe the controller sends a MSG command, waits for a reply or timeout, then sends one Poll.

Since the MSG command is triggered by logic and probably has a relatively long timeout value, the Polls will be infrequent enough that RSLinx/RSLogix won't be able to use them to effectively go online.

Thanks. That was a world of help. We're now going to try to "pass through" to the 5/04 from the PLC 5/20 at channel 0. Or we can try one of those 1784-U2DHP converters for $2,100. Ouch!

godfrey said:

Thanks. That was a world of help. We're now going to try to "pass through" to the 5/04 from the PLC 5/20 at channel 0. Or we can try one of those 1784-U2DHP converters for $2,100. Ouch!

Click to expand...

A little cheaper here.

http://www.ind-concepts.com/Allen_Bradley_PLC_Cables.htm

cable 1747-CP3

Hello could you help me, please.
What is wrong?? I create my own cable 1747-CP3,
I have 2 type of SLC 500, SLC5/03 and SLC5/04. I connected integrate serial port on my PC and RS232 port on PLCs.
I set on RSlinx RS-232 DF1 devices, but no communication

I read in manual the CPU 5/03 can use 1747-PIC. I tried the same cable as I use for PV 600, in RSLinx 1747-PIC/AIC+ driver but no communication too.