adccommunitymod (AutomationDirect) asked a question.
Created Date: October 17,2007
Created By: tektips2007
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I have a setup that I am trying to understand. System is working; I am just trying to figure out what they did. I have a controller that's talking ASCII on RS232. And on the other end I have a PLC that is talking ASCII on RS485. They are using a Black Box RS232 to RS485 converter plus. The PLC is connected via a 2 conductor TP wire from one side, which are connected to TXA and RXB. RXA/TXA are jumped and RXB/TXB are jumped. On the other side, the controller RS232 comm port is connected to the converter using a serial cable. This cable is RJ45 to DP-25 Male. The RJ45 male goes into the controller commport, and the DP-25 connects to the converter. When I checked the cable pin-out I noticed the following mapping: RJ45 DP-25 1 (blue) 2 2 (orange) 6 3 (black) 3 4 (red) 7 5 (Green) 4 6 (yellow) 8 7 (Brown) 5 8 (Gray) 20 Looking at the above pin-out, I am not sure why this cable was wired like that? It doesn't look like the standard RJ45 to DP-25 wiring, I am confused?
Created Date: October 17,2007
Created by: tektips2007
OK I have figured this one out. It turned out to be that the RS232 commport pin-out is non standard. Once I got the pinout things lined up correctly. The cable also was a null modem.
Created Date: March 07,2011
Created by: Magneto
I have a setup that I am trying to understand. System is working; I am just trying to figure out what they did.
I have a controller that's talking ASCII on RS232. And on the other end I have a PLC that is talking ASCII on RS485. They are using a Black Box RS232 to RS485 converter plus.
The PLC is connected via a 2 conductor TP wire from one side, which are connected to TXA and RXB. RXA/TXA are jumped and RXB/TXB are jumped.
On the other side, the controller RS232 comm port is connected to the converter using a serial cable. This cable is RJ45 to DP-25 Male. The RJ45 male goes into the controller commport, and the DP-25 connects to the converter. When I checked the cable pin-out I noticed the following mapping:
RJ45 DP-25
1 (blue) 2
2 (orange) 6
3 (black) 3
4 (red) 7
5 (Green) 4
6 (yellow) 8
7 (Brown) 5
8 (Gray) 20
Looking at the above pin-out, I am not sure why this cable was wired like that? It doesn't look like the standard RJ45 to DP-25 wiring, I am confused?
Interesting! I had exactly the same problem with a RS232 to RS485 converter but found out that even the RS232 interface have a standard configuration I still needed to use a null modem adapter. :confused:
Created Date: October 17,2007
Created by: tektips2007
I have a setup that I am trying to understand. System is working; I am just trying to figure out what they did.
I have a controller that's talking ASCII on RS232. And on the other end I have a PLC that is talking ASCII on RS485. They are using a Black Box RS232 to RS485 converter plus.
The PLC is connected via a 2 conductor TP wire from one side, which are connected to TXA and RXB. RXA/TXA are jumped and RXB/TXB are jumped.
On the other side, the controller RS232 comm port is connected to the converter using a serial cable. This cable is RJ45 to DP-25 Male. The RJ45 male goes into the controller commport, and the DP-25 connects to the converter. When I checked the cable pin-out I noticed the following mapping:
RJ45 DP-25
1 (blue) 2
2 (orange) 6
3 (black) 3
4 (red) 7
5 (Green) 4
6 (yellow) 8
7 (Brown) 5
8 (Gray) 20
Looking at the above pin-out, I am not sure why this cable was wired like that? It doesn't look like the standard RJ45 to DP-25 wiring, I am confused?