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7000 series readout system: Difference between revisions
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The oscilloscope readout system produces a pulse train consisting of 10 successive negative-going pulses representing a possible character in a readout word, and is assigned a time-slot number corresponding to its position in the word. Each time-slot pulse is output at -15 V onto one of ten lines, labeled TS-1 through TS-10 (Time Slots 1 through 10), which are connected to the vertical and horizontal plug-in compartments. | The oscilloscope readout system produces a pulse train consisting of 10 successive negative-going pulses representing a possible character in a readout word, and is assigned a time-slot number corresponding to its position in the word. Each time-slot pulse is output at -15 V onto one of ten lines, labeled TS-1 through TS-10 (Time Slots 1 through 10), which are connected to the vertical and horizontal plug-in compartments. | ||
Two output lines, row and column, are connected from each channel (two channels per plug-in compartment) back to the oscilloscope readout system. Data is encoded on these output lines as a pair of | Two output lines, row and column, are connected from each channel (two channels per plug-in compartment) back to the oscilloscope readout system. Data is encoded on these output lines as a pair of analog current sequences in 100 μA steps from 0 to 0.9 (rows) / 1.0 (columns) mA, which can address a matrix of 11 × 10 positions. In this matrix, rows 1, 2, 4, 5 and 6 correspond to characters whereas others are used to encode instructions: | ||
[[File:Tek7000-readout-charset.jpg|center|600px]] | [[File:Tek7000-readout-charset.jpg|center|600px]] | ||
In time slot 1, special operations can be requested that affect the display in later time slots. These commands are designed to simplify display changes required by external probes that request beam identification or change input sensitivity. The "Identify" command switches to an internal program displaying IDENTIFY instead of any encoded value. Command R3/C1 requests an additional zero to be added starting in time slot 5, R3/C2 adds two such zeroes, R3/C3 shifts the selected prefix one code to the left (i.e. | In time slot 1, special operations can be requested that affect the display in later time slots. These commands are designed to simplify display changes required by external probes that request beam identification or change input sensitivity. The "Identify" command switches to an internal program displaying the word "IDENTIFY" instead of any encoded value. Command R3/C1 requests an additional zero to be added starting in time slot 5, R3/C2 adds two such zeroes, R3/C3 shifts the selected prefix one code to the left (i.e. p → n, n → μ, μ → m, m → space), and R3/C4 shifts the prefix and adds a zero. (See the [[Media:Tek-plugin-readout.jpg|encoding circuit of the 7A18 plugin]] for an example implementation.) It is also possible to request a decimal point to be drawn without losing display digits, by encoding row 7 commands in time slot 1. | ||
Additionally R13 (row 13, selected by a row current of 1.3 mA) will produce a jump command by turning Q2153 off. This advances the display to the next channel, i.e. skips all following time slots of the current channel and their display. | Additionally, R13 (row 13, selected by a row current of 1.3 mA) will produce a jump command by turning Q2153 off. This advances the display to the next channel, i.e. skips all following time slots of the current channel and their display. | ||
Normally the readout will only display the channels of those plugins that are active as per the mode switches (P1018-P2118, channel inhibit), however individual plugins can override this by pulling the A35 ("override channel inhibit") line low. If the two channels of a plugin are inhibited, i.e. A35 is high at +15 V, two diodes (e.g. CR2163 and CR2162, with current sharing resistors) inject current into the A38/A37 line, effectively deleting the readout data by producing SKIP or space (C-0, R-x) instructions. | Normally the readout will only display the channels of those plugins that are active as per the mode switches (P1018-P2118, channel inhibit), however, individual plugins can override this by pulling the A35 ("override channel inhibit") line low. If the two channels of a plugin are inhibited, i.e. A35 is high at +15 V, two diodes (e.g. CR2163 and CR2162, with current sharing resistors) inject current into the A38/A37 line, effectively deleting the readout data by producing SKIP or space (C-0, R-x) instructions. | ||
===Plug-in circuit=== | ===Plug-in circuit=== | ||