Another modem question

[Pierre 1]

I have used the article in this site to connect an SLC5/03 via Modem and it works perfectly. My settings where: ... and also ... Now the problem I have is that I cannot establish a direct link with my Laptop. I use Autoconfig but it does connect. My HMI (EZ220 from AD) will also not connect to this PLC with those modem com settings. I have another empty CPU and it does connect OK, so my cables and stuff are correct. Any suggestions.

[mgvol 0]

If you are trying to use CH.0 on the SLC (serial port) to connect w/you laptop and/or HMI, you have to reconfigure CH. 0 Protocol Control to "No Handshaking" "CRC" Error Detection, and Embedded Responses "Enabled". If this is the case, why not use DH-485 on CH. 1 to connect to your HMI/Laptop?

[Pierre 1]

I could use my PIC box but I prefer not. 'cause its not real good with XP and also my HMI cannot go with a DH485 device. it only has a serial port. Can I not have a communication configuration that can be connected to by a modem AND by my laptop serial port? Just like I do with all the other PLC I connect to....

[Eddie Willers 2]

Do not assume your cables are correct for this configuration. You have configured the port to work with a modem using RTS/CTS handshaking. That's the "Full Duplex Modem" setting. Is the cable for your computer wired to do the same ? You swap pins 7 & 8, just like Pins 2 & 3 are swapped for Tx and Rx. The A-B 1747-CP3 cable has this wiring already in place. Does your HMI have the ability to use handshaking ? You might get away with an HMI cable that has pins 7 & 8 jumpered together, to emulate handshaking because there is no modem delay.