Is it possible to connect a PC directly to a SLC 500 5/02 CPU?

I recently inherited some 5/04 CPUs and a single 5/02 CPU that I need to pull the programs from. The 5/04 CPUs didn't pose any problems. I simply connected directly to the RS232 port on the 5/04 from the RS232 port on my laptop and used the RSLinx DF-1/DH-485 driver.

The 5/02 gives me pause, since it only has an RJ45 port for DH-485. I was wondering if it's possible to connect my laptop directly to the 5/02 using a modular RS232 to RJ45 adapter and the RSLinx DH-485 driver. I don't want to buy a 1747-PIC adapter for a one-time use if I don't have to.

AratanAenor said:

I recently inherited some 5/04 CPUs and a single 5/02 CPU that I need to pull the programs from. The 5/04 CPUs didn't pose any problems. I simply connected directly to the RS232 port on the 5/04 from the RS232 port on my laptop and used the RSLinx DF-1/DH-485 driver.

The 5/02 gives me pause, since it only has an RJ45 port for DH-485. I was wondering if it's possible to connect my laptop directly to the 5/02 using a modular RS232 to RJ45 adapter and the RSLinx DH-485 driver. I don't want to buy a 1747-PIC adapter for a one-time use if I don't have to.

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no to be "that guy" but usually if you have a decent relationship with your local distributor they usually can lend out something like that for a day for free

Welcome to the forum.
I agree with 0949er, if you explain to them that you need the program out of the plc so you can look at the logic for an upgrade to a new system, that will really help (assuming that is what you are doing)
james

AratanAenor said:

I don't want to buy a 1747-PIC adapter for a one-time use if I don't have to.

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First I would not use a PIC because odds are you will never get it to work with your PC, I would use a UIC and they are cheap so even in a one time use https://www.plccable.com/allen-bradley-1747-uic-usb-to-dh485-usb-version-1747-pic-slc-500/

Never know when you will inherit more older SLC's

Welcome to the PLCTalk forum community !

The only practical way to get the program out of an SLC-5/02 is to use a 1747-UIC.

The time spent preparing a suitable computer (XPSP2 or SP3 or earlier, carefully patched and connected to a motherboard-native UART) to use a 1747-PIC or 1761-NET-AIC will exceed the cost of a 1747-UIC. The only "clone" anyone endorses is from PLCCABLES.com.

When I was an RA local rep, I loaned tools and helped with this sort of thing in my office all the time. All I asked for in return was the opportunity to review one system or subsystem for upgrade.

Along with seeing if you can borrow a UIC maybe you can take the 5/02 to them and they can pull the program and put it on your flash drive with the CPU in a bench rack.

Or see if any other local shop has a UIC that call pull it for you.

But, with so many SLC's out there I would suggest getting a UIC - even the 5/03's, /04's and /05's DB-9 port can be configured to DH485 (that needs the UIC) often setup for a Panelview.

I do want to answer this question directly:

[is it] possible to connect my laptop directly to the 5/02 using a modular RS232 to RJ45 adapter and the RSLinx DH-485 driver.

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It is not.

The sole network port on an SLC-5/02 controller is Data Highway 485, which as the name suggests, uses RS-485 3-wire signalling. To connect to it from a computer, you need a device with an RS-485 transceiver, not an RS-232 transceiver.

Those include the classic 1747-PIC with its ribbon cable and 25-pin RS-232 connector, and the 1761-NET-AIC "AIC+", as well as the modern 1747-UIC USB to DH485 interface.

Also, the network port on an SLC-5/02 has +24V on Pins 3 and 8, so you can easily damage devices by connecting those pins to a non-DH485 device.

The DH485 protocol can run on a network link that has RS-232 on both sides. But that doesn't apply to an SLC-5/02 CPU.

Thank you for the suggestions and information. I will look into purchasing a 1747-UIC. I don't see SLC 500s often, but occasionally (like now) we acquire an older plant that has them. So it probably wouldn't hurt to have a UIC in my cable drawer.

+1 for the unit offered by Geniusintraning. I have used that unit myself and it works great with windows 10. At that price it is worth it to have one on hand.

Ken Roach said:

...as well as the modern 1747-UIC USB to DH485 interface.

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Excuse my ignorance, would perhaps some of these work?



https://www.mouser.com/Search/Refine?FS=TRUE&N=254076+4284914240+4292906361




Or does DH485 not ride on top of standard RS-485?

Not AB, but years back I made the equivalent of a Mitsubishi SC-09.

I had to use a RS-232 - Reverse RS-485 converter, (for 2 channels) with separate AC adapter, then make a custom cable for the PLC side. A SC-09 turns out would have cost less and a lot less work finding pinouts and making the cable.

A standard RS485 converter might work for a DB-9 port set to DH485, but the SLC5/02 in the OP only has the RJ45 connector and he would have to make a custom cable to use it, plus the external AC adapter (and if I remember its own extension cord because no outlet was ever close enough).

Excuse my ignorance, would perhaps some of these work?
https://www.mouser.com/Search/Refine...240+4292906361
Or does DH485 not ride on top of standard RS-485?

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From what I understand Data Highway 485 (DH485) is not the same as RS-485 and you cant just use a USB to 485 converter to make things work. You have to remember who you are dealing with here, Rockwell. Nothing is easy or cheap

"Why can't this random RS-485 device work with Data Highway 485" is just the English translation of "Warum funktioniert dieses gerät RS-485 nicht mit Profibus DP?"


Data Highway 485 really does use ordinary RS-485 transceivers. They're referenced to a common wire that is isolated from the rest of the circuitry, which gives nodes good immunity to ground loops and induced noise.

But it's a token-passing protocol with fairly tight timing requirements. It's not asynchronous, like DF1 or Modbus or ASCII, or packet-based like TCP/IP.

General-purpose devices that convert from USB or some other protocol or standard to RS-485 don't necessarily know when to switch from transmit to receive. Even on modern computers, a comms driver located several layers of electronics and operating system and application from the device can't get the timing right.

I spent a LOT of time in the late 1990's trying to get USB devices to work with DH485 and Windows. It was all wasted effort. Even the Indian-made hardware that eventually became the 1747-UIC wouldn't work until engineers in Cleveland made it work.

Ken Roach said:

"Why can't this random RS-485 device work with Data Highway 485" is just the English translation of "Warum funktioniert dieses gerät RS-485 nicht mit Profibus DP?"

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LOL.


thanks for answering my query.


The interesting thing is that the -UIC device connects a serial comm port (rs-232 or rs-485), so I suspect there are some extra smarts in the pay-extra-for cable.

The 1747-UIC uses a microcontroller that runs the DH-485 token-passing protocol on one serial port, and implements a DF1 Full Duplex driver over a USB serial port on another.

Because DF1 is asychronous, it runs fine over a modern Windows USB serial port.

On versions of RSLinx Classic from before there was a 1747-UIC driver, you could set up a DF1 driver with the 1770-KF3 device type and it would run the 1747-UIC just fine.