CAMAC 16-Bit ADC Scanning Module

The 3516 is a single-width CAMAC module that converts 32 analog voltages into their equivalent digital values. This module contains a high-resolution 16-bit analog-to-digital converter capable of resolving one part in 65,536.

The inputs are scanned, and the results are stored in a 32-word memory, which can be read via the Dataway. The number of active (scanned) channels is software programmable. There are two software-selectable scan modes: Continuous and Single-scan.

In Continuous mode, CAMAC Read cycles are asynchronous with the conversion process, eliminating overhead due to testing for converter busy.

CAMAC 16-Bit ADC Scanning Module: 3516

3516 Data Sheet

Supporting Chassis

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If it is desirable to synchronize scanning and reading, Single-scan mode can be used. In Single-scan mode, a LAM status is set after the last channel has been converted. In addition, the external trigger input can be used to synchronously trigger a single scan on multiple 3516s.

The 3516 contains a 4-bit, 32-word memory that can be loaded, on a channel-by-channel basis from the Dataway, with an appropriate gain factor for each differential input channel. Eleven gain values, from one to 1024, are available in binary progression. This allows one 3516 to measure a wide variety of input signal types (such as thermocouples, RTDs, high-level inputs, etc.). The C1B option features a single-pole, lowpass filter at the input of each channel. These filters provide a –3dB cutoff frequency of 6Hz. When channel scanning is initiated, channel inputs are selected in succession.

When a channel is selected, the preloaded gain factor is applied to the input signal, the amplified signal is converted, and the resultant binary information is stored in the on-board memory. Conversions take place at the rate of one every 250 microseconds (all 32 channels require eight milliseconds). The memory is configured in a dual-port fashion to facilitate retrieval of data with CAMAC block transfer operations. The 3516 is factory calibrated for inputs of ±10 volts.

All input signals are brought to the module through a 68-position high density SCSI connector mounted on the front panel. The external trigger can be brought in through a single-pin LEMO connector. Alternately, the 3516 may be strapped to accept an external trigger from the Dataway P1, P2, or P3 lines. An N LED flashes whenever the module is addressed, and an ACTIVE light indicates when the module is powered and scanning is activated. A LAM LED is illuminated when a LAM request is pending.

To facilitate the use of this module in temperature monitoring systems, Channel 1 can be strapped to receive an isothermal reference from a V792-ZA11 Isothermal Termination Panel. Alternatively, this channel may be used to monitor any analog data.

For monitoring 4-20 mA control loop signals, standard practice is to mount a precision 250Ω resistor external to the module (usually at the termination panel). This allows the 3516 to be removed from the circuit without disturbing the current loop. The V765-ZA11 Termination Panel can be used for this purpose.

CAMAC Module Features

  • 32 Channels
  • 16-Bit Resolution (1 Part in 65,536)
  • Programmable Gain from 1 to 1024
  • Programmable Number of Active Channels
  • Self-Scanning
  • External Trigger
  • Internal Buffer Memory
  • Differential Inputs
  • High-Frequency Noise Filtering on Inputs
  • Optional 6 Hz Low Pass Filters
  • Unipolar & Bipolar Operation
  • Strap-Selectable Inputs for Temperature References

CAMAC Module Ordering Information

3516 Products and Part Numbers
32 Channels, 16-bit Scanning ADC,
32 Channels, 16-bit Scanning ADC,
with Filters, 68P SCSI
32 Channels, 16-bit Scanning ADC,
with 30 Hz Filters, 68P SCSI
32 Channels, 16-bit Scanning ADC,
with 100 Hz Filters, 68P SCSI