Schematics EL-3034 through EL-3039 show the layout for one each of the Opto-22 relay racks used in the instrument electronics. The sheets have a block in the upper left-hand area that associates a channel number and a bit number with a function. The channel number gives the location of the I/O module on the individual rack. The bit number gives the I/O bit that the software can read or write and the function tells what the bit toggles or reads.

In the lower left area is a pictorial representation of the actual I/O rack. The drawing shows where the relays are and what their function is. It also tells what relay should be plugged into each slot. Notice that between each relay and its screw terminal is noted what color relay should be installed. The other important piece of information shown here is the position of the various bus bars. These are Sheet metal strips that are used to connect from two to eight terminals together.

On the right-hand side of the drawing is a table showing the destination or the output connections of the I/O relays. The first column gives the I/O bit for programming. The pin column refers to the screw terminals on the edges of the relay racks. The next three columns give the connector and pin numbers that the output is connected to. The sixth column tells what relay part number populates each position on the relay rack. The last column tells the function that the relay controls. On the right-hand side of the table are the channel numbers as labeled on the board.

Close Grating Clamp 1: I/O bit 25 is toggled to cause Grating Clamp 1 to clamp. (More info)

Open Grating Clamp 1: I/O bit 26 is toggled to cause Grating Clamp 1 to unclamp. (More info)

Close Grating Clamp 2: Bit 27 is toggled to cause Grating Clamp 2 to clamp. (More info)

Open Grating Clamp 2: Bit 28 is toggled to cause Grating Clamp 2 to unclamp. (More info)

Open Hatch: Bit 29 is toggled to cause the Entrance Hatch to open. (More info)

Close Hatch: Bit 30 is toggled to cause the Entrance Hatch to close. (More info)

Close Grating Clamp 4: Bit 31 is toggled to cause Grating Clamp 4 to clamp. (More info)

Open Grating Clamp 4: Bit 32 is toggled to cause Grating Clamp 5 to unclamp. (More info)

Close Grating Clamp 5: Bit 33 is toggled to cause Grating Clamp 5 to clamp. (More info)

Open Grating Clamp 5: Bit 34 is toggled to cause Grating Clamp 6 to unclamp. (More info)

Grating Moving: Bit 35. This relay powers the red Moving limit LED on the Grating manual pushbutton station. (More info)

Grating 3 In Place: Bit 36. This relay powers the green In Place limit LED on the Grating #1 manual pushbutton station. (More info)

Grating 4 In Place: Bit 37. This relay powers the green In Place limit LED on the Grating #2 manual pushbutton station.(Not implemented)

PRM Enable: Bit 38 is wired to the PRM optical slotted switch. When activated, the input from the switch is valid. The Primary Reference Mark is part of the grating select system. (More info)

Dewar Ion Pump Pushbutton: Bit 39 is wired across the dewar Ion Pump Controller's red start switch. When activated, it turns on power to the controller. If the ion pump current is too high, above about 50 milliamps, the power will not stay on. (More info)

Vessel Ion Pump Pushbutton: Bit 40 is wired across the vessel Ion Pump Controller's red start switch. When activated, it turns on power to the controller. If the ion pump current is too high, above about 50 milliamps, the power will not stay on. (More info)

Slitmask Fiducial Enable: Bit 41 is wired to the various optical slotted switches used in the slitmask system. When activated, the inputs from the switches are valid. (More info)

Slit Stage In Place: Bit 42. This relay powers the green In Place limit LED on the slitmask manual pushbutton station. (More info)

Slit Stage Moving: Bit 43. This relay powers the red Moving limit LED on the slitmask manual pushbutton station. (More info)

Retract Slitmask: Bit 44 is toggled to cause the slitmask to be removed from the slitmask form. (More info)

Insert Slitmask: Bit 45 is toggled to cause the slitmask to be inserted into the slitmask form. (More info)

Bits 46 - 48 are not used.