AD11-K

This user manual for the AD11-K Analog to Digital Converter (part of the PDP-11 series) describes a 12-bit A/D converter module designed by Digital Equipment Corporation.

Key features and functionalities include:

• Conversion: It converts analog data to digital values (12-bit, right-justified offset binary) at high speeds, supporting a multichannel throughput rate of 50 kHz (22 µsec conversion time).
• Input Channels: It offers flexible input options, switch-selectable between 16 single-ended or pseudo-differential channels, or 8 true differential channels. Input voltage ranges (e.g., ±5V, ±10V, 0-10V) are configurable via jumpers. Inputs are over-voltage protected.
• Control: Conversions can be initiated by program control, an external input, or real-time clock overflow. A status flag is set upon completion, and interrupts can be enabled.
• Integrated DAC: The module also includes an 8-bit Digital-to-Analog Converter (DAC) with a ±2V output, primarily for self-testing but also available for user applications.
• Physical Design: The AD11-K is a single quad-size module (A009) that mounts in a PDP-11 SPC slot, requiring +5 Vdc power. RFI shields are recommended for noise reduction.
• User Interfacing: Analog signals are connected via a 40-pin I/O connector (H854), with support for grounded, floating, twisted pair, and shielded inputs. An optional H322 distribution panel is available.
• Configuration: The module's operation mode (single-ended/differential), input range, and register/vector addresses are configured using on-board solder jumpers and switches.
• Programming: It is controlled through a Status Register, which allows channel selection and status monitoring. Converted data is read from the A/D Buffer Register, and DAC values are written to the DAC Buffer. Register and vector addresses are user-configurable to avoid conflicts.