7000 Series plug-in interface

Tektronix 7000 series oscilloscope mainframes have one (7912) or two vertical plug-in slots, and zero (7612D), one (7xx3) or two (7xx4) horizontal plug-in slots.

The interconnect on either slot type is a 76-pin PCB edge connector. The pinout on vertical and horizontal slots is not identical but compatible to the point that vertical plugins can be installed in horizontal slots and vice versa. However, in that case, some functions may be unavailable − for example, trigger signals are only routed to H slots so a timebase in a V slot must be externally triggered.

Looking into the mainframe from the front panel, "A" pins are left of the connector centerline (on the plug-in PCB's component side) and "B" are on the right (on the plugin PCB's solder side). Pins are numbered from 1 at the bottom to 38 on the top. In the following table, (H) indicates signals available in horizontal slots only, (H-A) is horizontal slot A, (H-B) is horizontal slot B, and (V) denotes signals available in vertical slots only.

A side B side Pin Function Function 1 Sweep Gate (H) Delay mode ctl in (H-B) 2 Gate common Delay mode ctl out (H-A) 3 A Sweep (H-A,V) [note 1] B Sweep (H-B,V) [note 1] 4 Line trigger Trigger holdoff (H) 5 Chop drive Aux Swp gate (H) 6 Chop common ALT drive 7 Intensity Limit (H) MF Channel Switch 8 +5 V Sweep inhibit (H) 9 +5 V (lights) Delay gate (H) 10 Single sweep ready (H) X comp inhibit (H) 11 +Signal −Signal 12 Signal Ground Signal Ground 13 +Trigger (V) [note 2] −Trigger (V) [note 2] 14 Lights common Dual beam Aux Y-Axis (7844) 15 Single sweep logic Single sweep reset (H) 16 MF Mode Aux Y axis (H) 17 Aux Z axis Aux Z common 18 +15 V -15 V 19 +50 V -50 V 20 +Trigger in (H) −Trigger in (H) 21 +Aux trigger in (H) −Aux trigger in (H) 22 /EOI /SRQ 23 /DAV REN 24 /IFC [note 3] /ATN 25 /NDAC /NRFD 26 Logic Common /SND 27 -5.2 V [note 4] 5.1 V [note 4] 28 n.c. n.c. 29 TS10 TS9 (DIO8) 30 TS8 (DIO7) TS7 (DIO6) 31 TS6 (DIO5) TS5 (DIO4) 32 TS4 (DIO3) TS3 (DIO2) 33 TS2 (DIO1) TS1 34 n.c. n.c. 35 Force readout Plugin mode 36 n.c. n.c. 37 Ch. 1 Col Ch. 1 Row 38 Ch. 2 Col Ch. 2 Row Pin group function legend Plugin power HF signals Readout system signals IEEE-488 bus used in 7A16P, 7A29P, 7B90P, digitizer mainframes; data 1-8 on TS2-TS9 lines

Description of signals Sweep Gate − 0/+5 V, high while sweep is running (beam unblanking); +Gate Output on mainframe uses Sweep Gate from H slot A when A Gate is selected, and from H slot B when B is selected Delay Mode Control − Output on delaying timebase in horizontal slot A, connected to input on delayed timebase in horizontal slot B. >+3 V disables auto sweep in delayed timebase; 0 V enables independent timebase function. A/B Sweep − 500 mVp-p, negative-going copy of sweep signal from timebase, not affected by X position control or magnifier; Used for mainframe's Sawtooth Out, additionally fed to V plugins Line Trigger − Approx. 1 VRMS mains-frequency signal from power supply (through transformer) Trigger Holdoff − Chop Drive − Chop Mode Sense − Aux Sweep Gate − Alt Drive − Intensity Limit − Switched to ground by timebase in slow sweep speeds (≥100 ms/Div), limits beam intensity to protect the CRT phosphor Mainframe Channel Switch − Sweep Inhibit − Delay Gate − +Gate Output on mainframe uses Delay Gate from H slot B when Delay Gate is selected Single sweep ready − X comp. inhibit − Connected to ground in amplifiers, switched to ground by timebase set to amplifier (X-Y) mode to enable X-Y delay compensation in scopes with that function (7904 Opt.2, 7104 Opt.2) Signal − Signal output from plugin to mainframe. Differential, 50 Ω per side. 50 mV/Div (differential). Trigger − Copy of signal output from V plugin to mainframe. Differential, 50 Ω per side. 50 mV/Div (differential). Terminated on H slots. Aux Y-Axis − Current-driven input to mainframe allowing vertical separation of two traces with dual timebase plugins. Dual Beam Aux Y-Axis − Single Sweep Logic − Single Sweep Reset − Switched to ground to reset single sweep. Mainframe Mode − Aux Z Axis − Current-driven input to mainframe allowing plugins to modulate beam intensity, e.g. in dual timebase A intensified by B display mode. Trigger In − Trigger signal input on H plugin, routed from V plugin's trigger output. Differential, 50 Ω per side. Aux Trigger In − GPIB lines − Control signal functions are the same as their IEEE-488 (GPIB) equivalents. Time slot lines 2 to 9 double as IEEE-488 data lines. TS1−TS10 − readout system time slot pulses. Idle 0, active −15 V. Force Readout − Plugin Mode − Ch1/2 Row/Col − Analog current inputs to the readout system. Ch1 refers to the first channel within the plugin slot in question and is associated with the readout field on top of the screen. Ch2 is the 2nd channel displayed at the bottom. Row/Current signals accept negative currents in 100 μA steps; typically, plugins contain resistors from time slot signal lines to row/current lines.

Notes

[note 1] output from H plugins, input on V plugins

[note 2] output from V plugins, unused and terminated 50 Ω to ground in mainframe H slots

[note 3] in programmable mainframes, A24 is pulled high to +3 V, indicating to programmable plug-ins to use TS2-TS9 as GPIB lines and a modified readout logic using only TS1 and TS10.

[note 4] not provided by most mainframes (digitizers only?). 7A16P connects B27 to A9, requires -5.2 V on A27.

Links

• Kahrs, Interfacing to the Tektronix 7000 series