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Old May 29th, 2015, 07:57 AM   #10
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Originally Posted by solojayda3rd
Hello all, I have an allen Bradley 1747 UIC serial to USB converter which works perfectly fine on our Micrologix 1000 via a 1761-CBL-PM02 cable. However when I try to connect to the Micrologix 1200 I get nothing on RSwho in Rslinx.

I've tried the recommended settings, 19200 Baud, error checking CRC, parity None, Stop bit 1, Full duplex, Device SLC-Cho/micro/panelview as well as 117-Kf3/1747-KE and all the different station numbers

I know the com port is set right, and I can use the exact same set up and connect to a micrologix 1000 right now. Just not the 1200. I 've tried two different 1200's and I've tried using the dcomm button as well...

I "think" you may be assuming that all MicroLogix 8-pin mini-Din ports are configured the same and that you only need to have the computer configuration correct to communicate with any, or either of these controllers?

NB: The 1747-UIC will only communicate with ports configured for the DH-485 Protocol.

MicroLogix controller communication ports can be configured to use a select number of Protocols, depending on the model.

For the MicroLogix 1000 Series C or higher, you have either DF1 or DH-485. Depending on the Series, the port has either been manually set for the DH-485 Protocol or has auto sensed a DH-485 device is communicating with it and used Automatic Protocol Switching (Series D or higher) to temporarily switch from the DF1 Protocol to the DH-485 Protocol, to communicate with your 1747-UIC.

The MicroLogix 1200 Channel 0 port may currently be configured for the DF1 Protocol, or other. It does not support Automatic Protocol Switching. So it cannot automatically change the currently configured Protocol to the DH-485 Protocol, and so the 1747-UIC cannot establish a connection.

Using the DCOMM option sets the MicroLogix 1200 Channel 0 port to the default DF1 Protocol. Again, this is of no use as the 1747-UIC is looking for the DH-485 Protocol.

Originally Posted by solojayda3rd
Yeah I've been suspecting the UIC myself, it IS a usb to serial converter from what I understand but I've also heard better things about the keyspan.
But the UIC is also a Protocol converter, which is not what you appear to need here. You just want to pass DF1, not convert it. You need an adapter that just "adapts" USB Serial to RS-232 Serial, such as the Keyspan you mentioned.

If you need to communicate with a controller that is configured for DF1, and you do not have an RS-232 Serial port on your computer, then you must use a "USB to Serial" converter that just converts USB Serial wiring to RS-232 Serial wiring and streamed Serial data to bit-wise Serial data (they all do), but does not perform any Protocol conversion.

Rockwell Automation sell the "9300-USBS" USB to serial adapter, which is more expensive...

9300-USBS (DF1)
The 9300-USBS adapter is used in place of a built-in serial port. It communicates DF1 protocol to serial devices via DB 9 connector with appropriate cabling (i.e. 1747-CP3, 1761-CBL-PM02, 2711-NC13, etc.).

Other popular third party adapters which have been successfully used are the...

Belkin F5U103
Keyspan USA-19W
Keyspan USA-19QW

I have also successfully used and still own an Aten Technologies UC232A adapter.

The main reason that many of the third party adapters do not work, or will only work intermittently with DF1, is timing. Many adapters do not handle the necessary throughput required for the Protocol timing. Because they need to buffer and process the streaming USB Serial data into the RS-232 bit-wise format, many USB-Serial adapters' chipset are not quite up to the task, with regard to DF1. For other applications, the adapter may work successfully, and so point the blame back at RSLinx and its driver, or the attached cable, or even the controller.

Depending on the adapter used, RSLinx may see a device sometimes or not all, due to timeouts waiting for a response.

Older versions of the 9300-USBS used a Prolific chipset, which worked in most cases it was used in, but it did have some issues along the way. The sometimes troublesome Prolific chipset was eventually replaced by the more stable FTDI chipset used in the last few years for the 9300-USBS.

The FTDI chipset is used in many of the available adapters. So it is not exclusive to RA. If using USB-Serial adapters for DF1 communications, and they are not of the proven ones above, and you have issues, then check into which chipset they use. Just having an FTDI chipset does not necessarily guarantee success with DF1, but it gives them a fighting chance.

Choose well.

"A little nonsense now and then is relished by the wisest men".
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