Data Monitoring RS-422 Lines

[Scaz]

Hello,

I need some recommendation on how to implement my system. I will have a DB-25 Female connector that I need to monitor four signals on. It will be a one-way communication of each of the four signals. I need to find a way to bring all four signals to a laptop and monitor the data in the signals in labview with minimal amount of connectors as possbile. The pinouts on the DB-25 female connector are as follows:

Pin 1 - Unused

Pin 2 - Unused

Pin 3 - COMMON

Pin 4 - Unused

Pin 5 - Unused

Pin 6 - Shields

Pin 7 - Unused

Pin 8 - Unused

Pin 9 - COMMON

Pin 10 - Unused

Pin 11 - Unused

Pin 12 - Line 1 (+)

Pin 13 - Line 1 (-)

Pin 14 - COMMON

Pin 15 - Line 2 (+)

Pin 16 - Line 2 (-)

Pin 17 - Line 3 (+)

Pin 18 - Line 3 (-)

Pin 19 - COMMON

Pin 20 - Line 4 (+)

Pin 21 - Line 4 (-)

Pin 22 - Unused

Pin 23 - Unused

Pin 24 - Unused

Pin 25 - Unused

Thank you for the help.

[nyc_(is_out_of_here)]

DAQ

[Scaz]

Thank you for the response but I was looking for a little more help than that, like what DAQ hardware would work for my system. I need to connect to a laptop so either a PCIM or chassis type system would be needed. Any other recommendations would be appreciated. Thank you.

[nyc_(is_out_of_here)]

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@Scaz wrote:

Thank you for the response but I was looking for a little more help than that, like what DAQ hardware would work for my system. I need to connect to a laptop so either a PCIM or chassis type system would be needed. Any other recommendations would be appreciated. Thank you.

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I am not understanding what is so special about your requirements that would require more help.

[Dennis_Knutson]

The data has nothing to do with RS422 so your subject line is misleading. lYou have not provided nearly enough information to recommend specific hardware. Nothing about signal levels, frequency, etc. What is PCIM and why would you need a chassis instead of a USB DAQ device?

[Scaz]

My DB-25 connector is a tap-off connection to 4 RS-422 serial links as mentioned before. There is a data message of approximately 375 bytes sent on each line. The data is sent once every 105ms or 9.523 Hz. The baud rate of the data message is 1.2288 Mbps. The data consists of a variety of data types (i.e booleans, Unsigned INT, NUM, etc). I need to view this data in real time on my laptop and also do some analysis on the data. My questions is what would be the best hardware to use to acquire the data. I understand what DAQ is and a USB DAQ device would be fine for me. I was just inquiring what hardware you recommend. I am new to labview so if I am wasting your time, I apologize and you can just let someone else answer the question if it bothers you.

[Dennis_Knutson]

An RS422 has a differential pair for each line so each channel would be 4 lines for transmit and receive. If your device has just the transmit lines, then you would need 4 separate RS422-receivers. Please attach a manual for the device that you are connecting to.

[Scaz]

Sorry, I am not able to post the manual here. To clarify, my four tap-offs are 2 RS-422 lines so a total of 4 lines that I need to monitor (2 RX and 2 TX). My thought was to use a USB DAQ to bring all of the connections from the DB25 connector, then wire 4 individual RS-422 DB-9 connectors and connect to a 4 port usb serial adapter, but NI usb serial adapters only support up to 460.8 kb/s and I need 1.2288 Mbps. The other option I suppose is to setup a PXI box with with a 4 port serial hub and DAQ, but I was hoping to find an option that could all be done through USB.

[Dennis_Knutson]

A DAQ card can't be used for serial communication either. The pxi device from NI goes up to 3Mb.

[K C]

If you just want to see the data of each RS-422 line just connect a RS-422 receiver or RS-485 interface to it.

Write a program that collect the data of each line and you have your monitor.

Gets a bit more difficult if you want to have the messages line-up in time. Also depends on the protocol that is used.