XiO Inc

Wiring has always been the necessary evil of control systems. We all take for granted that thousands of wire points need to be carefully prepared before a machine can be turned on. A technician cuts a wire, strips a wire, perhaps installs ferrules, lables the wire and then inserts the ends into terminal blocks and carefully torques down the screws.  When automation professionals look at the figure to the right, they are not surprised. It’s part of the territory.

Control Wiring Properties

In this brief piece on wiring and the profound changes that Soft-I/O brings, we are going to talk about this figure a bit. Before we go too far, let’s list some remarkable facts:

1. Consider the amount of panel or enclosure area to hold your control system. Fact: More area is taken up by wiring and terminal blocks than by the controller itself. Often it’s a factor of three! Note the ratio at the right. It’s more than two to one.
2. A normal rule of thumb is that each wire point takes 30 minutes during control system build, including drawings, labor, labeling and debug. That’s a huge cost.
3. A recent study by the semiconductor industry found that the main cause of failure of wafer processing tools was wiring.

Network Wiring Properties

Now, let’s contrast the wiring required to build a control system with the type and amount of wiring required to build an office computer. Here are some facts about building and configuring office computers:

1. A wire stripper is never used.
2. All connections are made via connectors.
3. Software is used to configure the connections. DIP switches and jumpers are a thing of the past.

I know what you are going to say. The computer industry builds millions of computers. It’s unfair to compare the office computer with an industrial control system. Really? Really? Let’s see about that.

PLC Wiring

Let’s look more closely at the figure to the right. At the top of the photo is an old-style PLC, unchanged for the past 50 years save a plastic case and a bit smaller size. At the bottom of the picture is a valve manifold with 14 valve positions. A common 25-pin D-style connector mounted on the valve manifold serves to connect the valve manifold to the PLC. The purpose of the vast wasteland of terminal blocks between the PLC and the valve manifold is to do two things:

1. Adapt the signals on the valve manifold D-connector to the fixed-format of the PLC.
2. Bring in power to actuate the valves since the PLC does not supply power.

Soft-I/O Wiring Advantage

Soft-I/O profoundly changes how wiring is done, and we are going to show just how different the result is. And, yes, we are going to ask that you compare our solution to the office computer solution, a totally different problem but a solution just as elegant and not based upon high volume production.

Now let’s look at where all the wires and terminal blocks come from.

The figure to the right is a schematic of the valve manifold connection to the PLC. Actually, it’s a tiny part of the valve manifold in the photo above, because the real one would be too dense for a normal screen. What are all the wires?

Here are some of the factors that lead to complex wiring with old-style PLC’s:

1. The PLC does not supply power, so a power supply needs to be wired in.  That's the extra "Device Power Supply".
2. The power supply needs to be referenced to the PLC.
3. The valve manifold handles commons differently than the PLC, so the terminal blocks are used to sort things out.

Now, let’s look at the schematic for the valve manifold hooked up to Soft-I/O. It looks much simpler. How come?

1. Soft-I/O provides power on its I/O pins, unlike the old-style PLC, so there is no "Device Power Supply".
2. Soft-I/O is therefore automatically referenced to the valve manifold.
3. Soft-I/O configures itself to the pinout of the valve manifold, so there is no need to “sort things out”.  In fact, there are no terminal blocks at all.  A standard cable simply connects the connector on the valve manifold to the connector on the Soft-I/O module.
4. Every unused pin on the Soft-I/O module is spare and available to connect any other sensor or actuator.  Compared to the old-style PLC's where there is typically poor utilization of input/output channels, with Soft-I/O, every pin can be used.

The photo on the right shows Soft-I/O connected to the same valve manifold as in the first picture. Where are all the terminal blocks? Where is the power supply? Here are the details:

1. The power for the valves comes from the Soft-I/O module on the correct pins.
2. The return path from the valve manifold back to the power supply is through a common pin or multiple common pins which are configured on the Soft-I/O module.
3. Because the Soft-I/O module and the valve manifold use the same modern D-connector, we simply employ a standard cable. Nothing is custom!
4. Software is used to configured the Soft-I/O pins for their correct function. No DIP switches or jumpers.
5. Not a single terminal block is employed!

Please compare the photo to the right with the second photo above.  The two photos depict very much the same functional system.  The upper, old-iron system employs hundreds of wires requiring a week of wiring time for a technician.  The lower photo of Soft-I/O demonstrates how a standard cable and a single part number module can outperform the old-style PLC I/O systems.

Conclusion

Let’s go back to the outlandish claim that we made at the start of this note that we would introduce a method of wiring a control system that was as simple and effective as wiring an office computer. Yes, it’s a totally different paradigm.

• Office computers achieve their plug-compatible nature by building millions of units;
• Soft-I/O delivers the same connected simplicity via a configurable connectorized input/output system.

It’s so unique, it’s patented many times over!