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Wiring Between the Interlock Controller and Individual Interlocks and In-Tool Interlock Wiring Considerations

General Considerations

Each Coral interlock controller card is capable of controlling either 24 or 25 Coral interlocks depending on how you choose to connect wires between your interlock controller card and individual interlocks. The interlock controller has an output IDC connector with 2 rows of 25 pins. Looking at the IDC connector of an installed board, the top two pins will control channel number 1, the next pair of pins will control channel number 2, .... and the bottom pair of pins will control channel number 25 on that board. In one way or another, as described in this section, these 25 pair of signals will ultimately be split out into either 24 or 25 pairs of RJ-11 "phone" connectors that will each connect to one interlock.

Coral interlocks are enabled with a short pulse of +12V applied to the appropriate terminals of each interlock and are disabled with a short pulse of -12V applied to the interlock. Following the application of the enable or disable pulse, the actual state of the interlock is examined by the application of a +5V pulse and measuring the current that is flowing through the input of the interlock under those conditions. A properly enabled interlock will return a measured current of about 3500 microamps (that is 3.5 mA) and a properly disabled interlock will return a measured current of about 900 microamps (that is 0.9 mA). If the polarity of the interlock is reversed (by, for example, connecting the wiring into the wrong "phone jack" in the interlock) the diodes in the interlock circuit will be reverse biased and will return a current of approximately zero ... which is hte same current that would be returned if there were no interlock connected at all.

Because control of the interlocks requires application of sufficient voltage at the interlock to appropriately change the state of the interlock from enabled and disabled and vice versa, there is a maximum wiring length between the interlock controlled card and each interlock. In general, as long as the one-way wiring length between the interlock controller card and each interlock is no more than about 500 feet, the interlock controller card should reliably control each interlock. While this is not a hard limit and you don't need to worry about carefully measuring wiring length, this is a reasonable maximum wiring lenght to consider. In most instances, this means that you will likely be able to connect to about any interlock in a single building. It is likely, however, that you will need an interlock controller card in each building if you operate a laboratory that has tools in more than one building.

Note
Each of the following wiring options uses a sequence of splitters and cabling to get from a single 25-pair IDC connector to wiring that reaches either 24 or 25 individual interlocks. Particularly because CAT-3 or CAT-5 cables can either be cross- or straight-pinned, it is easy to lose track of the proper signal polarity between controller card and each individual interlock. I recommend not worrying about this and suggest that you not even try to trace out the polarity from IDC connector to interlock. I always end up with a headache when I try to do that. The saving grace is that each interlock has a pair of RJ-11 jacks that are electrically reversed from one another. While this was expressly added to allow daisy-chaining of interlocks as described in one of the CAT-3 options, the other benefit is that each interlock can be made to work regardless of the wiring polarity. In particular, as long as the interlock signals are coming in on the pair of wires that you expect (the default 3 and 4 or, optionally either 2 and 5 or 1 and 6) it doesnt really matter which polarity is in use. For example, if everything works as it is designed, the enable/disable signal should appear on pin 4 and the return signal (ground, typically) will be on pin 3. If this is the way that the signals reach your final RJ-11 connector, then the interlock should work properly if the RJ-11 connector is plugged into the leftmost RJ-11 jack on the interlock. What is wires got crossed? Simply plug the RJ-11 into the rightmost RJ-11 jack. When I'm hooking up a new interlock, I start by connecting my RJ-11 connector into the leftmost RJ-11 jack. If the interlock enables and disables properly, I am done. If it is not, I simply move the phone cable to the rightmost RJ-11 jack and things will normally work properly then.

Wiring Options Using Existing CAT-5 Wiring

Many people will consider using CAT-5 wiring as the "back bone" of a Coral interlock wiring strategy. In this case, each CAT-5 cable will carry the interlock signals for four tools. By using an appropriate "splitter" at the tool end of that CAT-5 cable, you will be able to split the 4 pair of interlock signals into four separate "phone wires" that will plug into each interlock.

Note
Adoption of any of the CAT-5 wiring approaches describe here only allows you to use 24 of the 25 avialable channels on a Coral interlock controller because each CAT-5 cable will carry signals for 4 channels and 6 CAT-5 cables each carrying 4 signals for 4 channels will control a maximum of 24 tools.
Warning
Depending on your building infrastructure, you may be able to use existing CAT-5 wiring for much of the wiring between equipment controller and individual interlocks. If you chose to adopt this approach, you need to make sure that none of the CAT-5 wires used to carry actual interlock enable/disable signals connect to or try to "go through" network switches or routers. The +12V and -12V signals used to enable and disable indivual interlocks is not compatible with network switches and routers and may damage them.

Starting at the ISA controller board and moving to the individual interlocks, here is what you will need. In general, I've tried to list reasonably accessible vendors, but there is likely nothing magical about the part numbers that I've described here. I normally use either Digi-Key (www.digikey.com) or BlackBox (www.blackbox.com) for convenience but you are free to make your own choices. I will also try to note the number of parts that you will need for each controller board. Note: each controller board can be used to interlock 25 pieces of equipment. However, if you are using the described CAT-5 wiring in which each CAT-5 wire will carry interlock signals for 4 different tools, you will only be able to interlock a total of 24 pieces of equipment with each controller board.

The ISA controller board has a keyed and shrouded 50-pin male IDC connector on the end of the board that will extend out the end of your chassis.

To connect the IDC connector on the board to some ribbon cable, you will need a 50-pin female IDC socket connector. This actually consists of 3 parts: the socket connector, a strain relief, and a pull tab. So you will need the following Digikey parts:

  • 1 ea AKC50H-ND Socket connector with polarizing key
  • 1 ea ASSR50-ND Strain relief for socket connector
  • 1 ea ASPS50-ND Permanent Pull Tab

You will need an appropriate length of 50-wire ribbon cable to get from your controller board to the start of your CAT-5 wiring. For this I use the following Digikey part number with the length of the cable (in feet) replacing the "X" in the following part number:

  • 1 ea MC50G-X-ND Gray 0.050in pitch ribbon cable.

A ribbon-cable to 50-pin Telco male connector (and strain relief). These are Digikey part numbers:

  • 1 ea MDB50K-ND Delta Conn 50 position plug w/insert
  • 1 ea MDSF50-ND Metal strain relief

A harmonica that converts a 50-pin Telco connector to 6 RJ45 connectors. This is a BlackBox part number:

  • 1 ea FM052-R2 6 RJ45 T568B ports to 50-pin Telco Female

Note: for the above, I find that a vise with smooth faces works well for attaching these connectors to the ribbon cable. In each case, pin 1 of the connector should be attached to the red strip on the ribbon cable.

At this point, you can use a combination of CAT-5 wiring including building infractructure, patch panels, jumper cables, etc, to get close to a cluster of tools. Ideally, you will end up either with a CAT-5 Cable or a RJ45 jack so that a total of 4 tools are each within 7 feet of this connection point.

Finally, you will need a RJ45 modular splitter to break out the wiring of a single CAT-5 cable with 4 pair of interlock signals into 4 separate interlock cables. For this you will want to use one of the following from BlackBox:

  • 6 ea FM805-R2 RJ45 Modular Splitter (Pinning B)

or

  • 6 ea FM825-R2 RJ45 Modular Splitter (Pinning B)

Each of these split a single CAT-5 wire into 4 CAT-5 jacks where each pair of wires on the incoming jack is connected only to the central 2 wires (pins 4 and 5) of the 4 outgoing jacks. The only difference is that the FM805-R2 has an input connection that is a RJ45 jack if you will be connecting this to an existing length of CAT-5 wiring or need to have this splitter a distance of greater than 2.5 inches from the nearest jack. The FM825-R2 is identical except that it has a very short (2.5 inch) CAT-5 cable and a RJ45 jack attached to the input side of the splitter.

Finally, you need to be able to connect the RJ45 connector on the output side of the splitter to the RJ11 connector in each interlock. Ideally, this is a length of 6-conductor phone wire with a RJ11 plug on one end and a RJ45 connector on the other. While you could easily build your own, I've found that a company named IEC Cable in Commerce City, CO (www.iec-usa.com) makes exactly this cable with either straight or crossover wiring patterns in a 7' length. The IEC part numbers are:

  • 24 ea L0532 RJ11 to RJ45 6 Conductor Crossed Cable 7'

or

  • 24 ea L0533 RJ11 to RJ45 6 Conductor Straight Cable 7'

Note: by the time you get through all of these various connections, adapters, CAT-5 wiring, etc. the polarity of the signal is hard to trace. Fortunately, each interlock box has a pair of RJ11 jacks that are wired in a mirror image of the other. In principle, if everything was wired correctly, the interlock would work properly when the phone cable is plugged into the leftmost of the two jacks. However, if things are reversed, the interlock will work properly if it is plugged into the rightmost jack. This can also be corrected by selecting either a crossed or a straight cable as the final length of cable between the splitter and the interlock. You may find it useful to first buy a few L0532 crossed cables and a few L0533 straight cables to see which works best for you.

Wiring Options Using CAT-3 Wiring and an 8-way Splitter

Some facilities may consider using CAT-3 wiring as the "back bone" of a Coral interlock wiring strategy. In this case, each CAT-3 "phone wire" cable will carry the interlock signals for four tools. In this case, each 6-conductor "phone wire" will contain the interlock signals for three interlocks. Rather than using a splitter, we can simply daisy-chain these interlocks as long as we are careful to configure each interlock so that it is "listening" to a different pair of wires. By default, each interlock comes pre-wired so that it normally will connect to the centrail two wires (wires 3 and 4) on a 6-pin RJ-11 connector. However, each interlock has moveable jumpers that allows it to be configured so that it will "listen" to pins 2 and 5 or to pins 1 and 6. In this way, if three interlocks are configured so that they connect to pins 3 and 4, pins 2 and 5, and pins 1 and 6, respectively, then on 6-conductor RJ-11 cable that carries the interlock signals for all three interlocks may be daisy-chained from one interlock to another and each of these interlocks may be separately controlled by thre sequential channels on the interlock board.

Note
Adoption of any of this CAT-3 wiring approach described here only allows you to use 24 of the 25 avialable channels on a Coral interlock controller because each CAT-3 cable will carry signals for 3 channels and 8 CAT-3 cables each carrying 3 signals for 3 channels will control a maximum of 24 tools.
Warning
Most "phone wires" with a RJ-11 connector on each end only have wires connected to pins 2 through 5. In other words, pins 1 and 6 do not have wires connected to them. This approach requires cabling that has 6-conductor wire connected to a RJ-11 connector at each end. While those can be purchased in a variety of lengths, you may also want to consider purchasing a spool of 6-conductor phone wire, a number of RJ-11 jacks, and a RJ-11 stripping/crimping tool and building your own 6-conductor "phone wires" in lenghts that you require.

Starting at the ISA controller board and moving to the individual interlocks, here is what you will need. In general, I've tried to list reasonably accessible vendors, but there is likely nothing magical about the part numbers that I've described here. I normally use either Digi-Key (www.digikey.com) or BlackBox (www.blackbox.com) for convenience but you are free to make your own choices. I will also try to note the number of parts that you will need for each controller board. Note: each controller board can be used to interlock 25 pieces of equipment. However, if you are using the described CAT-5 wiring in which each CAT-5 wire will carry interlock signals for 4 different tools, you will only be able to interlock a total of 24 pieces of equipment with each controller board.

The ISA controller board has a keyed and shrouded 50-pin male IDC connector on the end of the board that will extend out the end of your chassis.

To connect the IDC connector on the board to some ribbon cable, you will need a 50-pin female IDC socket connector. This actually consists of 3 parts: the socket connector, a strain relief, and a pull tab. So you will need the following Digikey parts:

  • 1 ea AKC50H-ND Socket connector with polarizing key
  • 1 ea ASSR50-ND Strain relief for socket connector
  • 1 ea ASPS50-ND Permanent Pull Tab

You will need an appropriate length of 50-wire ribbon cable to get from your controller board to the start of your CAT-5 wiring. For this I use the following Digikey part number with the length of the cable (in feet) replacing the "X" in the following part number:

  • 1 ea MC50G-X-ND Gray 0.050in pitch ribbon cable.

A ribbon-cable to 50-pin Telco male connector (and strain relief). These are Digikey part numbers:

  • 1 ea MDB50K-ND Delta Conn 50 position plug w/insert
  • 1 ea MDSF50-ND Metal strain relief

A harmonica that converts a 50-pin Telco connector to 8 RJ-11 connectors. This is a BlackBox part number:

  • 1 ea FM031 8 RJ-11 USOC ports to 50-pin Telco Female

Note: for the above, I find that a vise with smooth faces works well for attaching these connectors to the ribbon cable. In each case, pin 1 of the connector should be attached to the red strip on the ribbon cable.

At this point, you can use a combination of CAT-3 wiring including building infractructure, patch panels, jumper cables, etc, to get close to a cluster of tools. Ideally, you will have a collection of three tools that will be relatively close to one another so that you can daisy-chain from the the "harmonica" to the first toool, on to the second tool, and finally on to the third tool.

Finally, you need to be able to connect the RJ-11 connector on the output side of the splitter to the RJ-11 connector in each interlock. This is a length of 6-conductor phone wire with a RJ-11 plug on each end. While you can easily build your own, Digikey makes these in either straight-pinned or cross-pinned version in prefabricated lengths of 4, 7, 14, and 25 feet. You will need a total of twenty four of these RJ-11 cables in appropriate lengths. The Digikey part numbers are:

  • EL06M-04 RJ11 6-Conductor Cross-pinned Cable 4'
  • EL06M-07 RJ11 6-Conductor Cross-pinned Cable 7'
  • EL06M-14 RJ11 6-Conductor Cross-pinned Cable 14'
  • EL06M-25 RJ11 6-Conductor Cross-pinned Cable 25'

or

  • EL06MS-04 RJ11 6-Conductor Straight-pinned Cable 4'
  • EL06MS-07 RJ11 6-Conductor Straight-pinned Cable 7'
  • EL06MS-14 RJ11 6-Conductor Straight-pinned Cable 14'
  • EL06MS-25 RJ11 6-Conductor Straight-pinned Cable 25'

Note: by the time you get through all of these various connections, adapters, CAT-3 wiring, etc. the polarity of the signal is hard to trace. Fortunately, each interlock box has a pair of RJ11 jacks that are wired in a mirror image of the other. In principle, if everything was wired correctly, the interlock would work properly when the phone cable is plugged into the leftmost of the two jacks. However, if things are reversed, the interlock will work properly if it is plugged into the rightmost jack. This can also be corrected by selecting either a cross- or a straight-pinned cable. You may find it useful to first buy a few EL06M cross-pinned cables and a few EL06MS straight-pinned cables to see which works best for you.

Wiring Options Using CAT-3 Wiring and 25-way Splitter

This approach is conceptually the easiest and requires the fewest components. It has the advantage that it allows you to make use of all 25 interlocks on a single interlock controller board. It is probably best suited to laboratories that have 25 tools to be interlocked in close proximity to one another. For labs that are organized in multiple rooms or various aisles or bays, this may not be the best approach. In this approach we break out the 50-conductor ribbon cable into a collection of 25 RJ-11 jacks that each have the interlock signal for one tool. In this case, each of the interlock signals will be on pins e and 4 (the center 2 conductors) of a standard RJ-11 phone cable.

Starting at the ISA controller board and moving to the individual interlocks, here is what you will need. In general, I've tried to list reasonably accessible vendors, but there is likely nothing magical about the part numbers that I've described here. I normally use either Digi-Key (www.digikey.com) or BlackBox (www.blackbox.com) for convenience but you are free to make your own choices. I will also try to note the number of parts that you will need for each controller board. Note: each controller board can be used to interlock 25 pieces of equipment. However, if you are using the described CAT-5 wiring in which each CAT-5 wire will carry interlock signals for 4 different tools, you will only be able to interlock a total of 24 pieces of equipment with each controller board.

The ISA controller board has a keyed and shrouded 50-pin male IDC connector on the end of the board that will extend out the end of your chassis.

To connect the IDC connector on the board to some ribbon cable, you will need a 50-pin female IDC socket connector. This actually consists of 3 parts: the socket connector, a strain relief, and a pull tab. So you will need the following Digikey parts:

  • 1 ea AKC50H-ND Socket connector with polarizing key
  • 1 ea ASSR50-ND Strain relief for socket connector
  • 1 ea ASPS50-ND Permanent Pull Tab

You will need an appropriate length of 50-wire ribbon cable to get from your controller board to the start of your CAT-5 wiring. For this I use the following Digikey part number with the length of the cable (in feet) replacing the "X" in the following part number:

  • 1 ea MC50G-X-ND Gray 0.050in pitch ribbon cable.

A ribbon-cable to 50-pin Telco female connector (and strain relief). These are Digikey part numbers:

  • 1 ea MDE50K-ND Delta Conn 50 position plug w/insert
  • 1 ea MDSF50-ND Metal strain relief

A splitter that converts a 50-pin Telco connector to 25 RJ-11 connectors. This is a BlackBox part number:

  • 1 ea 31525 25 RJ-11 USOC ports to 50-pin Telco Male

Note: for the above, I find that a vise with smooth faces works well for attaching these connectors to the ribbon cable. In each case, pin 1 of the connector should be attached to the red strip on the ribbon cable.

At this point, you can use a combination of CAT-3 wiring including building infractructure, patch panels, jumper cables, etc, to get close to a cluster of tools. Ideally, you will have a collection of three tools that will be relatively close to one another so that you can daisy-chain from the the "harmonica" to the first toool, on to the second tool, and finally on to the third tool.

Finally, you need to be able to connect the RJ-11 connector on the output side of the splitter to the RJ-11 connector in each interlock. This is a length of 4-conductor phone wire with a RJ-11 plug on each end. While you can easily build your own, Digikey makes these in either straight-pinned or cross-pinned version in prefabricated lengths of 4, 7, 14, and 25 feet. You will need a total of twenty four of these RJ-11 cables in appropriate lengths. The Digikey part numbers are:

  • EL04M-04 RJ11 4-Conductor Cross-pinned Cable 4'
  • EL04M-07 RJ11 4-Conductor Cross-pinned Cable 7'
  • EL04M-14 RJ11 4-Conductor Cross-pinned Cable 14'
  • EL04M-25 RJ11 4-Conductor Cross-pinned Cable 25'

or

  • EL04MS-04 RJ11 4-Conductor Straight-pinned Cable 4'
  • EL04MS-07 RJ11 4-Conductor Straight-pinned Cable 7'
  • EL04MS-14 RJ11 4-Conductor Straight-pinned Cable 14'
  • EL04MS-25 RJ11 4-Conductor Straight-pinned Cable 25'

Note: by the time you get through all of these various connections, adapters, CAT-3 wiring, etc. the polarity of the signal is hard to trace. Fortunately, each interlock box has a pair of RJ11 jacks that are wired in a mirror image of the other. In principle, if everything was wired correctly, the interlock would work properly when the phone cable is plugged into the leftmost of the two jacks. However, if things are reversed, the interlock will work properly if it is plugged into the rightmost jack. This can also be corrected by selecting either a cross- or a straight-pinned cable. You may find it useful to first buy a few EL04M cross-pinned cables and a few EL04MS straight-pinned cables to see which works best for you.

Connecting Interlocks in Invididual Tools

Selecting the location in a particular tool to insert a Coral interlock can only be made by someone familiar with the inner workings, electronics, and existing interlocks on that particular tool. In many cases that will be the maintenance engineer responsible for that tool or, in some cases, even the manufacturer of that tool.

Warning
Installing an interlock on a tool often requires opening and performing work in areas of the tool that are normally inaccessible. This may included opening panels. for example, that are normally intelocked. There may be lethal voltages in the area where the interlock is connected. There may be toxic gases, chemicals, or other hazards inside the tool. Inserting Coral interlocks in a tool may invalidate a warranty on that tool. Particularly in the case of new tools or tools under warranty or service contract, you should work with the tool vendor or service supplier to discuss Coral interlocking issues.

In virtually all cases, the Coral interlock will behave as if it is a pare of closed contacts when the tool is enabled and an open-connection between those two contacts when the tool is not enabled. The low-power interlock is rated to handle a maximum current of 1 Amp at 24 VDC or 0.3 Amp with 115 VAC. In general, low-power interlocks should not be used to switch on/off AC power to a tool. The high-power interlockis rated with a maximum current handling cpaability of 15 Amp at 120 VAC. In the rare event that you need to control something that has higher current or voltage demands than that, you can use a high-power interlock to drive a larger relay. Such a design should only be handled by a properly registered engineer or contractor.

When interlocking a particular tool, you need to identify a location to insert the interlock where it will achieve the following results:

So, where can an interlock be installed to be effective?

Most more complex tools already have a series of interlocks assocaited with them. For example, they may have vacuum interlocks to prevent process gases from flowing if unless the tool is under vacuum. There may be interlocked doors that prevent normal operation of the tool if those doors are open. For example, equipment with high voltage sources are typically interlocked to prevent access to an area where high-voltages may exist. Many tools have either flow or pressure switches to indicate the presence of important utilities such as cooling water or fumre exhaust, for example. Some tools have additional, unused interlock inputs that will prevent the tool from operating correctly unless that interlock is a closed pair of contacts.

On a tool that has one or more interlocks, we cannot tell you which of these may be most suitable for use as a Coral interlock. In many cases, one or more of these interlocks may prevent the tool from operating properly unless that interlock is "made" .... that is, the actual interlock is a pair of closed contacts. For example, let us assume that you have a tool that has a flow switch in the cooling water supplied to this tool that will open if water flow is too low and close if the actual water flow is more than the required amount. In this case it might be appropriate to insert a Coral low-power interlock in series with this water flow switch. In this case, a tool that is not enabled will appear to the tool as if it has inadequate water flow. If the tool is enabled AND if the tool has adequate water flow, then the tool will function normally. If EITHER the tool is not enabled OR if the tool has inadequate water flow, it will note operate properly.

Warning
In general, most interlocks are SERIES-connected sets of contact closures. In these cases, a Coral interlock will typically be placed in series with existing interlocks. Placing an interlock in parallel with an existing interlock will prevent that interlock from properly protecting you or the equipment because the Coral interlock would effectively bypass the real interlock when the tool is enabled.
Note
Using this strategy, a tool that is not enabled will think that it has a cooling water problem. It is easy for someone to forget to enable such a tool, see that the equipment reports a cooling water problem, and write that up as an equipment failure. When maintenance personnel come to look at that equipment, if they are note aware or have forgotten that the cooling water interlock on the tool is in series with the Coral interlock, they may spend valuable time trying to diagnose a cooling water flow problem that is really a case of a tool that was simply not enabled. We have found that it is useful to purchase and use the Coral-compatible "ON" indicator as a visual reminder that the tool is hardware interlocked and so that it is clear when the tool is actually eanbled.

Note: some contact closure interlocks are likely not good choices for inserting a series-connected Coral interlock. For example, tools with EPO (Emergency Power Off) buttons are usually wired so that pushing the EPO button opens a set of contacts that control power to the entire machine. In this case, inserting a Coral interlock in series with the EPO button is likely not a good choice because removing power from the entire machine is often more drastic than you need. Other contact closures may not do enough to prevent tool operation. For example, on PVD tools such as ebeam evaporators and sputtering equipment, the pumpdown time can often take much longer than the actual time spent depositing a film. If you interlock only something that prevents the actual deposition from occurring, your lab members will likely quickly learn this and only enable the tool during the few minutes of the deposition.

What about tools that don't have existing interlocks which are suitable for insertion of the Coral interlock? Many tools require a keyboard or mouse to operate properly. It is straghtforward to interrupt a mouse or keyboard in a USB or PS2 device (usually the 5V line) with a Coral interlock. This does "hack up" the mouse or keyboard cable. You also have to be careful that you don't have folks walking around with a spare mouse or keyboard in their back pocket to replace the interlocked mouse or keyboard. What about even simpler tools? In many cases, for a tool that has no existing interlocks, you have no other choice but to interrupt either AC power, or in the case of tools with microscope lights you can often interrupt either AC power to the microscope light power supply or the lower-voltage connection to the lamp itself. In either of these cases you will likely need to use a high-power interlock box.