converting a RS485 bus to TCP/IP.

[RTSI01]

Hello,
Im having trouble with a design. We are a security company working on a project to replace existing RS485 Access Control system with an IP based system. the current setup is connected via RS485 with each controller series'd into the 485 bus to an end of line. Is it possible to turn that existing infrastructure into a IP over 485 and maintain the series of controllers?

 

[FvM]

You mean IP over serial (RS485), not serial over IP? In other words keep the RS485 wiring and controller hardware, but replace serial protocol based controller firmware with IP protocol capable firmware?

I think, you'd spend less effort if you implement the ethernet to rs485 gateway as protocol converter, keeping the existing controller firmware.

 

[RTSI01]

You mean IP over serial (RS485), not serial over IP? In other words keep the RS485 wiring and controller hardware, but replace serial protocol based controller firmware with IP protocol capable firmware?

I think, you'd spend less effort if you implement the ethernet to rs485 gateway as protocol converter, keeping the existing controller firmware.

The current hardware is obsolete. The new hardware is IP based. Does the the converter work in utilizing the existing infrastructure and converting the points along the bus to IP and back to a switch at the headend?

 

[KlausST]

HI,

I guess you need serial over IP.
For this there are ready to buy modules available.
I´m not sure wheter they work module-to-module. But surely PC-to-module.

Do an internet search for "RS485 over ethernet module" and check whether this is what you need.

Klaus

 

[FvM]

Does the the converter work in utilizing the existing infrastructure and converting the points along the bus to IP and back to a switch at the headend?

I didn't talk about a specific converter, just tried to find out what you want to achieve and consider how I would probably solve the problem.

The picture isn't completely clear yet. Many details have to be considered, e.g. how's the RS-485 wiring topology, presume the new endpoint hardware has only ethernet interface, where can converters be placed, what's planned for the central controller.

Is it possible to turn that existing infrastructure into a IP over 485 and maintain the series of controllers?

What do you exactly mean with "maintain the series of controllers" when you also say the hardware is obsolete?

 

[dick_freebird]

Why is there not an IP brain to talk to all these IP appliances? Keeping
low-BW RS-485 at the head would mean all that Ethernet bandwidth
is being paid for (in the purchase price), to waste.

Make a clean break and pull everything you say is obsolete. Of course
a lot of it probably isn't, really, but somebody says so, so pull the Band-Aid
off.

If you got this gear from a stand-up vendor they probably would have
field folks to help you get it up in your plant. But those folks are not
likely to have any interest in your "vintage" wireball.

 

[FvM]

If the problem is only reusing existing twisted pair wiring, point-to-point connection with VDSL modems can be a solution. 100/100 Mbit over up to 300 m telephone cable, up to 1.4 km with reduced throughput.

 

[mamakaia]

Transitioning from an RS485-based access control system to an IP-based system while maintaining the existing infrastructure can be challenging, but it's possible with the right approach. Here are some key considerations:

1. IP over RS485 Converters: There are devices known as IP over RS485 converters which allow you to send IP data over RS485 wiring. These converters can be used to integrate your existing RS485 infrastructure with the new IP-based system.
2. Topology Considerations: RS485 operates in a multi-drop bus topology, which means devices are connected in series along the bus. This differs from typical IP network topologies, which are often star-based. Ensure that the converters you choose can support the daisy-chaining of devices in your current setup.
3. Bandwidth and Speed: RS485 supports lower data rates compared to modern Ethernet-based IP networks. Assess the bandwidth requirements of your new IP-based access control system to ensure the existing RS485 infrastructure can handle the data traffic.
4. Compatibility: Ensure the new IP-based controllers are compatible with the RS485 to IP converters. This includes considerations for power requirements, data protocols, and physical connectors.
5. Cable Quality and Distance Limitations: The quality of the existing RS485 cables and the distances involved can affect signal quality. Check the maximum distance supported by the converters and compare it with your existing setup.