Prosoft Modbus Communication card

Does any one connected to Prosoft Modbus card via modem.
I am having hard time communicating via modem.
I can directly connect to 3150-MCM modbus card via Wintech Modscan32 via serial cable without any problem.
but if i connect via modem i immediatley get "modbus message time out" in my wintech software after both modem establish communicaiton.

My 3150-MCM port 1 is configured as Modbus Slave. Address 1, Baud rate 9600, non parity, 1 stop bits. RS232 , Modbus RTU protocol

I am able to read Input status 1xxxx and Holding register 3xxxx serially via my com port 1 using Wintech Modscan32

But when i dial via modem to port1. both modem gets connected but no RX, TX going on or no data.

I used AB/Zycom Remote access modem kit (9300-RADKIT). I also tried Motorollo 3460 Fast modem same result.

the pin configuration that i used are as below.

3150-MCM Modem
RX (2) ------- TX(3)
TX (3) ------- RX(2)
DTR(4) ------- DSR(6)
GND(5) ------- GND(5)
DSR(6) ------- DTR(4)
RTS(7) ------- CTS(8)
CTS(8) ------- RTS(7)

My PC side i used null modem cable to connect my PC to Modem.

I read 3150 User manual several times and also did connection as per manual page no.50 which is opposite to the above wiring. but same result.

where am i making mistake.

I am having tough time with this MCM card as well as my customer as i am unable to read via modem.

Any help / wiring diagram or conection diagram please.

If required i will even post my ladder logic. but donot know how to attach files here.

many thanks. I hope some one will help. thanks.

This is a tough problem. Unless someone has specific experience with your EXACT configuration it is almost impossible to diagnose this one over a message forum.

The reason is that there is no standard modem configuration, and almost all of them depend on some PC driver software to assist with getting them to work when connected to a PC.

But PLC's have their own specific setup requirements, and cannot run the driver software. So you are pretty much on your own to read through ALL the documentation for both the modem and the PLC port and nut out each step on your own. This can be a very time consuming task, like days if you are lucky.

This is why AB packaged the Remote access modem kit (9300-RADKIT), and it was a nice idea to try it....but the 3150-MCM is not quite the same as the SLC Ch0 port.

You are right PhilipW. Today is my 6th day with this assignment. And i still donot have any correct answer. I am little bit nervous now as my customer is loosing confidence on me and hence lots of pressure from him to complete the job.
Things are getting worst now.
U are right if i ask the card manufacturer he puts the issue on the modem as its from different vendor.
so i am in between.

There is no specific example or wiring diagram on how to connect a modem in manual. what i found in manual is all wrong.

Yes it was pretty much simple and easy to connect AB Modem to SLC channel 0 than to Modbus card.

It took only 15 minutes for me to get connected to SLC 5/03 channel 0 port. where as it has taken me 6 days and no luck to connect to Prosoft modbus 3150-MCM slave port.

My customer is killing me every single moment. My god i just want to finish this job and escape from his plant.

So i need your help. IF some one has tried this configuration please do send me ur wiring connection.

My application. Dial to Modbus card(slave) and get details about Digital and analog input/outpus in SLC chassis.

The problematic thing is i find it difficult to understand all this communication terms and their use. CTS, RTS, DTR, DSR and lots of other AT commands. It seems to be a big field on its own.

What i thougt simple is real difficult now.

ok thanks for all your efforts & help.

See this thread for posting ladder

http://www.plctalk.net/qanda/showthread.php?s=&threadid=10913&highlight=pdf+file

Also you must use a straight thru cable.

I solved it with Prosoft tech support

Dear PhilipW and Mickey,
I finally solved with support from Jason sanders prosoft tech support engineer's email.

below his email. really excellent support. My god. i did as per that and everything went as per paper. thank god. I hope the below will some one in need of help.
so hyperterminal does lots of thing. so should check that out.
I too learnt a lot today. also solved the problem. so i am double happy. thanks for all your support.
Mickey your right straight through cable as per manual page no.50 is correct. but i used only pin 2, 3 and 5.


STEP 1. The simplest communications setup between two PCs is with one cable. First, make a direct connection between the two PC Com ports, run HyperTerminal on both PCs and you should be able to type on one PC and see the characters you type on the other PC. This will require only a null-modem cable between the two ports, one that crosses pins 2 and 3, i.e. TX Pin2 to RX Pin3 and RX Pin2 to TX Pin2. Once you can type characters on one PC and see them arrive on the other...go to the other and type characters back to the first PC and be sure you can receive them there. Once you have successfully established two-way communication in this fashion between the two PCs you are ready to go to STEP 2.

STEP 2. Next, insert your two modems between the two PCs. You will probably need to use plain, straight-through modem cables to connect between the PCs and the modems, i.e. TX Pin2 to TX Pin2 and RX Pin3 to RX Pin3. Set the modems for no hardware handshaking, check the baud rates, parity, data bits, stop bits, etc. If the modems have DIP switches, you will need to have them set correctly. If they have configuration software, you should use that to be sure they are properly configured. Your goal is to establish the same communications link between the two PCs like you had in STEP 1; only this time, you are doing it through the two cables, two modems and the phone line between the modems, instead of just the one cable, as in STEP 1. Until you can successfully accomplish this, you will not be able to establish a connection between our module and any other device through these modems. If two PCs running HyperTerminal cannot communicate through the modems, neither will our module.

Once you have the correct cables and modem configuration, so that the two PCs can communicate via HyperTerminal to each other through the modems, then you can use the same cables and modem configuration to communicate between our module and a PC running ModScan(32) or any other device, like your DCS, for instance. Until you can complete STEP 2, you will not be able to get our module to communicate with anything else through your modems.
-----end of email message from prosoft--------------------

I think your PC to modem link if failing to communicate because you're using a null modem cable.

Use a straight through modem cable for PC to modem.

Dan

I should have put more effort into my first post Ramsey. Jason's email is spot on.

Usually the most frustrating aspect of modems is the dammed Hayes command set which always struck me as an exercise in serious gobbledegook. No doubt it is easy if you work with it regularly, but each time I look at it it is back to square one.

Using Hyperterminal gives you visiblity on what the modem is doing, and quickly verifies cables, port configs etc. If you set Hyperterminal to behave exactly as the 3150 port, then the set up should all fall into place.