Making a SLC 500 cable

macrophobia · May 23, 2007

Hello all,

I want to connect a SLC 500 (cat#1747L20G) to the serial port on my laptop.

I was just going to create a pin1->1; pin2->2; etc cable, but reading this thread worried me:

http://www.plctalk.net/qanda/archive/index.php/t-9950.html

Has anyone else created a working cable for this situation before? Where should I look when the AB knowledgebase doesnt help?

Hakutsuru · May 23, 2007

Since the port is DH485, there's no way a simple cable will work. The voltage levels will be different and, if I'm not mistaken, the voltage from the PLC is much higher, so it could burn up the port on your laptop. You probably need the PIC module or some other kind of 232-485 converter.
I can't even get to the knowledgebase article, so I have no idea how helpful it should have been.

-jeff

JesperMP · May 23, 2007

1747L20G, that is one of the fixed rack SLC500's. And so it has a RJ45 port for DH485 comms, not a serial RS232 port.
You cannot make a cable yourself.
You have to purchase a 1747-PIC for RS232, or (the better choice) a 1747-UIC for USB.

macrophobia · May 23, 2007

Hakutsuru:Yes. I knew it was too simple to work. I should have known that.

I'll spend more time looking for the article and learning how to convert the signals. In the meantime, I will just order a new cable. Haha!

Thanks for your help!

Thank you also, JesperMP! Now I know what part to to order!

GMc · May 23, 2007

macrophobia,

Take a look at this thread. I think it's what you want.

GMc

JesperMP · May 23, 2007

You can not connect to a DH485 network from a PCs serial port by simply adding an RS485 converter.

Ken Moore · May 24, 2007

Take a look HERE for a less expensive option.

macrophobia · May 24, 2007

JesperMP said:
You can not connect to a DH485 network from a PCs serial port by simply adding an RS485 converter.

I like the product. You are saying that the converter won't work because of the differance in voltage, correct?

mordred · May 24, 2007

there is also a timing issue involved hence on some connections standard converters do not work which is why AB had to design the 1747-UIC on their knowledge base ther was amn article on the subject. However it appears to be down at the moment

Hakutsuru · May 24, 2007

macrophobia said:
I like the product. You are saying that the converter won't work because of the differance in voltage, correct?

No, in this case its not because of the voltages. The converter would take care of that problem. Its probably because DH485 is NOT simply DF1 converted to RS485. Same with DH+, they are different protocols. How, different? I don't know, but different enough.

As a contrast, if you had a modbus serial device and a modbus 422/485 device, you could connect them just by throwing an off-the-shelf converter in there.

-jeff

JesperMP · May 24, 2007

macrophobia said:
I like the product. You are saying that the converter won't work because of the differance in voltage, correct?

I dont know the intricate details why you cannot just convert RS232 to RS485 and be done with it. DH485 should operate with RS485 signals, but I think that there is something about the protocol that requires accurate timing that most RS485 converters cannot meet.
Try to search on the forum if you can see if someone else have succeded in using a non-AB RS232/RS485 converter.
The product Ken Moore linked to looks like a PIC clone, and not just an RS232/RS485 converter.

mordred · May 24, 2007

You are correct JesperMP I still wish I could track down that article on the AB knowledgebase. But the explaination you provided is prety much what it stated

Corbis · May 24, 2007

SLC500 Cable

I connected a RS232 to RS485 Converter to a DTAM Micro's RS485 port (DH485) in a point-to-point configuration. The converter handles the timimg (Driver enable)

Here is the topic Link

Regards,
Corbis

rsdoran · May 24, 2007

Corbis said:
I connected a RS232 to RS485 Converter to a DTAM Micro's RS485 port (DH485) in a point-to-point configuration. The converter handles the timimg (Driver enable)

Here is the topic Link

Regards,
Corbis

To make sure the issue does not get too confused. The DTAM Micro is RS485, not DH485 so there is a difference.

mordred · May 24, 2007

1747-PIC : Alternative Hardware Solutions

Question [font=Arial, Helvetica]1747-PIC : Alternative Hardware Solutions[/font]

Answer [font=Arial, Helvetica]PROBLEM:
[/font][font=Arial, Helvetica]The 1747-PIC will not communicate to the processor after you've exhausted all troubleshooting resources.
Your computer does not have a COM serial port. Only USB (Universal Serial BUS).[/font]

[font=Arial, Helvetica]SYNOPSIS:
The[/font] [font=Arial, Helvetica]Allen-Bradley 1747-PIC was originally designed to meet RS232 specifications. The 1747-PIC continues to adhere to these specifications. Unfortunately the computer manufacturing industry no longer sees the necessity to follow this specification. Often the timing and power the 1747-PIC requires from the computer serial port are lacking. Add in Windows 95/98/NT/2000/XP which "step in" to handle COM port resources and the problem compounds. Most notebooks today also have only USB ports. See item number 7) below for information on a USB to DH485 converter.

[/font][font=Arial, Helvetica]Following are alternative connections to the DH485 network.

SOLUTION:
[/font][font=Arial, Helvetica]Here are several alternative hardware solutions:
(Selections 5 & 6 require the 1747-PIC driver in RSLinx to utilise the DH485 protocol).
1) 1784-PCMK card and 1784-PCM4 cable.
2) 1784-KTX card or 1784-PKTX and 1784-CP14 to SLC DH485 port or Belden cable to 1747-AIC or 1761-NET-AIC.
[/font][font=Arial, Helvetica]3) 1770-KF3 - Refer to AB Hardware catalog p. 9-12 or AB's online catalog web site. [/font][font=Arial, Helvetica]www.ab.com[/font]
[font=Arial, Helvetica]4) 1747-KE - Refer to AB Hardware catalog p. 9-11 or AB's online catalog web site. [/font][font=Arial, Helvetica]www.ab.com[/font]
[font=Arial, Helvetica]5) 1747-CP3 or 1761-CBL-PM02 serial cable to 1761-NET-AIC; Belden cable to 1747-AIC to the SLC DH485 port.
6)[/font] [font=Arial, Helvetica]1747-CP3 or 1761-CBL-PM02 serial cable to 1761-NET-AIC; 1761-CBL-AS03, AS09 or 1784-CP14 cable to SLC DH485 port.
[/font][font=Arial, Helvetica]NOTE: The 1784-CP14 cable will not work from a KTX or PKTX to a 1747-AIC. It must be connected to a processor front port.
7) 1747-UIC (USB to DH485 converter) and 1747-C13 cable to processor front port or 1747-AIC; 1747-CP3 cable or 1761CBL-PM02 from 1747-UIC to 1761-NET-AIC+ or MicroLogix front port. (see the attached pdf document 1747-IN063B-EN-P for additional information and connectivity on the 1747-UIC).[/font]

Catalog Number: RSLinx
DocFullNum: P5776
Revision:N/A
Fixed in Revision: N/A
Package: RSLinx (All)
Modual: 1747-PIC to DH485

Making a SLC 500 cable

macrophobia

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Hakutsuru

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JesperMP

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macrophobia

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GMc

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JesperMP

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Ken Moore

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macrophobia

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mordred

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Hakutsuru

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JesperMP

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mordred

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Corbis

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rsdoran

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mordred

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