Block transfer error between PLC5/20 and 1784-T36

Deer

Member
Join Date
Jun 2002
Posts
124
Dear All,

I have one PLC 5/20 that connected with industrial computer 1784-T36.
The PLC5/20 consist are some DI, DO, Analog input, Analog output, and some RTD I/O module.
Right now the PLC 5/20 is still running normally, and there is no problem with them.
To day I would like to change or replace the Processor 5/20 (version C) with the new one PLC 5/20 processor (Version E).Purpose of this changes is we will have one spare processor that someday we can use this spare processor if there is a problem on existing processor.
Prosedure for replacing the processor are:
1)Upload program on old processor with RSLogix5
2)Save the program on our note book
3)Replacing the processor with the new one
4)Make same all the dipswitch on the processor
5)Download the program to the new one processor.
After that I going online with the new processor.
THE PROBLEM IS: after the processor already RUN, on the industrial computer 1784-T36 that use as HMI, there are message BLOCK TRANSFER ERROR.
If we put back or reseat the old processor to the chassis, there is no message BLOCK TRANSFER ERROR.
FYI, all the analog I/O run with propperly (Solid green on the analog I/O was appear).
Every time we change with the new processor, the "BLOCK TRANSFER...error" will appear.
Is there any possibility the new processor failed or damage?
Any suggest ?

Thanks and regards,

Deer
 
I think the "Block Transfer" message is misleading; any industrial PC should be using DH+, not Remote I/O. Which port on the PLC-5/20 does the T36 terminal plug into ? The top port should be DH+, the bottom one RIO Scanner by default.

If I recall correctly, the T36 variant was built and supported by Royal Wholesale Electric out in San Diego. If you have any contacts out there you might give them a ring.

The T35/T36 terminals are a little before my time, so I don't have more than guesses in this case.
 
I remember the T30's as being remote I/O devices (boy, that takes me back!), so I'm not surprised if the T36's are too.

I haven't tried it (and I lack the equipment to experiment), but when you upload a program, I don't know whether or not the Channel Configuration is included with the upload (it should be, but I'm not sure).

Open the project up in RSLogix and verify that channel 1B has all the remote I/O racks that it should have - namely the one(s) corresponding to the T36. If not, go online in program mode and do an Autoconfigure.

Also, search for the BTW/BTR that addresses the data to the T36, and see if there is check to see if the ERR bit is ON.

It sounds like you've done everything right (unless as Ken suggests, you put the RIO plug into the wrong port), so the system should be teilling you what's wrong. The BLOCK TRANSFER ERROR is saying that there is no communication (I think).
 
Hi Kent, Allen,

Thanks for your advised, but actually between PLC 5/20 and T36 does not use RIO protocol as you mentioned before.
Our system use the RS232 port as communication between them.
I already checked too all block transfer error bit on the BTR/BTW, but there is no error bit on the block transfer (and Analog I/O's have solid green).
Anyway, thanks for you advised, I will inform to you if we can solve of this problem.

Regards,

Deer
 
RS-232? Check the baud rate, stop bits, etc when you are on-line with the old PLC and when you're on-line with the new.

I think that RS-Logix does not overwrite (or at least gives you the option of not overwriting) Channel 0 configuration when you download (otherwise, you'd lose communcation as part the download.).
 
Allen makes an excellent point; the last thing any ladder logic editor does when it downloads is send an "apply pending port configuration changes" command. The port changes are only "pending" until that is complete, and it's easy to accidentally change the port settings of a port you're not using to download (i.e. the Channel 0 serial port settings if you're downloading over DH+ on Channel 1A).

I was incorrect about the 1784-T36 origin; it probably has an A-B label but was built as a custom terminal for Solar Turbines (now part of Caterpillar) and they do 100% of the support and parts for it.

The phone number for their factory support desk in San Diego is (858) 694-1616.

In Indonesia, they have two offices:
Bandung, Tel: 6222-600-3300
Jakarta, Tel: 6221-522-0945
 

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