The obsolescence parade just keeps rolling on. Anything with a chip in it is doomed to become obsolete sooner rather than later. You can’t blame the silicon vendors. Their production lines are valuable properties and they want to make the parts that are going to offer the most profit. That’s probably not the chip in your radio, dishwasher, or garage remote control. If that chip fails, you’re buying a new unit.
It’s the same in the automation world. It’s hard to keep old controllers, I/O, and sensor/actuator devices going when the parts aren’t available. That’s why I never blame Allen–Bradley or any other vendor for obsoleting devices like the 1761-NET-AIC. It just can’t be helped.
But that’s where we come in. RTA now has a replacement for the 1761-NET-AIC called the 515RTAAIC. It’s not a long term solution for a lot of customers (no one should be using old, obsolete controllers forever—but our replacement 515RTAAIC can give customers breathing room. They can have time to plan their conversion from some of the old serial controllers to new technology. There’s almost never any ROI in upgrading a control system, so with this module you can plan a more extensive enhancement to your product, your product line, and your factory infrastructure.
Other than the footprint, the new AIC is a direct replacement for the 1761-NET-AIC. It’s compatible with all the old Allen–Bradley controllers including MicroLogix, SLC and PanelView, and newer controllers (ControlLogix and CompactLogix). It connects the serial ports of PCs (if you still have one of those) to these networks. Its ports are completely pin compatible with the NET-AIC and it uses the identical communication rates used by the original AIC.
A key difference for us is that this product is our first product that isn’t a gateway. A gateway actually understands the protocol on the wire, decodes the data, and sends it out in some other protocol. The RTA AIC doesn’t do that. All it does is to move messages over different physical media. The old serial PLCs, for example, can send a read data table request using serial RS232 to the RS232 port of the RTA AIC. That request is then put on RS485, converted back to RS232 at the destination PLC, and processed by the PLC. The response message moves in a similar fashion back the other way. No data is decoded; no formats are changed; the message is not altered. The RTA AIC simply allows the message to travel over different media segments to get to its final destination.
The 515RTAAIC, just like the 1761-NET-AIC before it, can interconnect all your favorite Allen–Bradley controllers:
• SLC 500, 5/01, 5/02, and 5/03 processors (channel 1)
• SLC 5/03, 5/04, and 5/05 processors (channel 0)
• MicroLogix controllers
• Logix controllers
• 1756-DH485 ControlLogix module
• Operator interface devices
• Personal computer serial ports (or any 9-pin DTE serial port)