Modbus on port 1 of DL250 versus DL250-1

[aeriform]

Page 3-7 of http://www.automationdirect.com/static/manuals/d2user/d2uservol1.pdf says that port 1 for the DL250-1 and DL260 is capable of using the port as a Modbus RTU slave.

I have a DL250 (the old version of DL250-1) which is mentioned on the same page. Does the DL250 also offer Modbus RTU slave as an option? I've haven't been able to properly connect using custom NModbus code nor ModScan32 program. My windows 7 laptop is connected to a USB to DB9 to RJ12 adapter to port 1 on the DL250 CPU.

I get a Modbus message timeout when connecting to port 1 of the DL250 using ModScan64 and parameters:
Direct connection to COM1
Baud rate 9600
Word Length 8
Parity ODD
Stop Bits 1
RTU Standard or Daniel/ENRON/OMNI

When using custom code for NModbus the software hangs waiting for response buffer to fill up after transmitting a ReadHoldingRegisters.

When using the DirectNET loader version 1.3.0.5 I get an error in V memory when Reading the PLC, but I can still save an image.
When loading DirectSoft6 from Windows 7 I get the error PLC type (03001000) is not supported by any installed knowledge base.
Using the K Sequence protocol I can get H2-CTRIO configuration and monitor values.
When trying to run the comm link using a 250(-1), K Sequence or DirectNET, Address 1, COM1" I get a "Support for the PLC type specified in the link is not installed."

Is there other software I should be installing to get support for the specified link?

I'm able to connect through an H2-ECOM, but I would like to have Modbus functionality which the H2-ECOM version doesn't have...

When using a Windows XP SP3 laptop and getting rid of the USB to DB9 adapter so that there's a DB9 to RJ12 adapter only:
When loading DirectSoft6 I don't get any errors like I do when connecting using Windows 7.
I can still monitor H2-CTRIO.

Is Modbus connectivity even available on port 1 of the DL250, or is it just the DL250-1 that adds that functionality? My port 2 on the DL250 is not an option as it is already in use and I'm assuming it can respond to a Modbus request just like the DL250-1...

Do I need to upgrade for Modbus functionality?

[Controls Guy]

I'm pretty sure your 250 is fine.  I was using 250's as Modbus remote I/O in like 97 or 98 or so, and they were fine.  I'd imagine that far back, they weren't -1 units.

[aeriform]

After more failures to connect and reading http://www.hosteng.com/FAQFiles/DirectSOFT.htm#FAQ0022 that states "Port 1 is K-seq protocol only" I'm thinking that the DL250 doesn't support Modbus despite what page 3-7 from the current manual suggests and that Modbus RTU and DirectNET communication are available only with the DL250-1 update. My CPU has the most recent firmware from 2001.

Is there some place I can find an old revision of the manual for the DL250 like revision F before the DL250-1 came out?

[Mike Nash]

1997 manual here:

https://web.archive.org/web/19980113091942/http://www.plcdirect.com/docs/dl205/dl205man.htm

You may find a closer manual digging around in the Wayback Machine. I was getting page not founds for some of the years.

No Modbus mentioned in 1997 manual above.

Edit - Here's a 2000 manual: Oops, it is actually a 2002 manual with a history that doesn't reflect that.

https://web.archive.org/web/20001215052800/http://ftp.automationdirect.com/documentation/d2user/d2user.html

[ADC Product Engineer]

Mike beat me to it since it took me some time to dig up a manual from that era to look it up in.

As Mike said, it appears that the D2-250 (non -1) did not support MODBUS on PORT 1.

I apologize for your time spent, I will get the manual updated to reflect this information.

[Controls Guy]

Hmmmm....I must have been using Port 2 back then.

[aeriform]

Mike beat me to it since it took me some time to dig up a manual from that era to look it up in.

As Mike said, it appears that the D2-250 (non -1) did not support MODBUS on PORT 1.

I apologize for your time spent, I will get the manual updated to reflect this information.

Thank you ADC for confirming and updating the current manual!

Thank you Mike for the link to the old manual, it'll be useful for comparison.

@Controls Guy I figured you might be thinking of the second port. After umpteen years, little details get a little muddled.

The process has forced this newbie to know a whole lot more about PLCs and Modbus, so that's good... Thank you all again for the resolution.