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The OPA is designed for adding 16-bit ADC inputs and analog signal conditioning to embedded controllers.

The OPA has eight operational amplifiers with high input impedance, which by default converts industrial standard +-10V analog input signals to 0-4V analog signals. The 0-4V analog signal can then directly feed into the ADC, external or on-board.

These inputs are then compatible with many ADCs on existing TERN controllers that only only accept 0-5V input ranges.

An optional 8 channel, 16-bit ADC (ADS8344, TI) can be installed on-board. The 16-bit ADC provides 8 single-ended or 4 differential analog inputs (0-4V) with a precision of 65536 counts of resolution at up to 10 KHz sample rate. By moving the ADC onto a separate expansion board, you can also reduce noise associated with ADC chips mounted directly to the controller itself.

Any TERN programmable embedded controller can interface to the OPA’s 16-bit ADC via two TTL outputs (CLK, DIN), and one TTL input (DOUT). For applications requiring many ADC inputs, multiple OPAs can interface to a single TERN controller, sharing common CLK and DIN, with a separate DOUT input for each OPA.

For example, 2 OPAs, providing 16 channels of 16-bit ADC input, require only 2 TTL outputs and 2 TTL inputs. Sample programs (source code) are available for interfacing the OPA with any TERN controller.

All +-10V analog inputs are connected to the OPA via on-board screw terminals. The TTL I/O signals can be connected to the OPA via either screw terminals or pin headers.

The analog signal conditioning circuit outputs 0-4V signals, which are routed to pin headers for external use. A 4.096V precision reference with low temperature coefficient (100 ppm per degree C) is on-board and is also available on the screw terminal.

The OPA can be powered by 5.1V to 12V unregulated DC with on-board regulator. It also can be powered by a regulated external 5V DC.

Special customized versions of the OPA is available for OEM customers, supporting (for example) 4-20 mA analog inputs, or providing differing gain for voltage analog.

  • Measures 2.0×1.6 inches
  • Power Input: +5.1V to +12V unregulated DC, or 5V regulated DC.
  • 4.096V 100 ppm/C precision reference
  • 8 channels 16-bit ADC (ADC8344)
  • 8 op-amps, accept analog +- 10V
  • 3-wire TTL interface
  • Screw terminals

Similar expansion boards: Relay-7, OPS
Supported controllers: All

  • Includes 8 operational amplifiers for ?10V to 0-4V conversion
  • precision 4.096V reference
  • screw terminals or headers
  • Does not include ADCs.
Quantity Price
100 CALL


Add-on Options

No.Item Price
18 ch. 16-bit ADC (ADC8344) $30

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