Measurement Computing DAQFlex User Manual
Page 39
DAQFlex Message-based Firmware Specification
Hardware Reference – USB-2408 Series
39
Hardware features
16 analog input channels, numbered 0 to 15.
o
Analog input mode is configurable for single-ended (16 channels) or differential (8 channels).
o
Thermocouple mode requires a differential configuration.
Analog voltage input ranges:
o
±10V
o
±5V
o
±2.5V
o
±1.25V
o
±0.625V
o
±0.3125V
o
±0.15625V
o
±0.078125V
Analog thermocouple input range is fixed at ±0.078125V.
2 analog output channels, numbered 0 to 1 (USB-2408-2AO only).
Analog output range is fixed at ±10V
1 digital input/output port (8 bits).
1024 bytes of nonvolatile EEPROM memory; used for storing configuration information, calibration
data, and user data.
RATE takes a float value. An error is generated if value set is less than the device's minimum
sampling rate or greater than the device's maximum sampling rate.
Calibration operations
o
AICAL:LOCK locks the AICAL component from performing calibration operations on the analog
inputs. In order to calibrate the analog inputs, you must first unlock the component using the
AICAL:UNLOCK message.
o
AOCAL:LOCK locks the AOCAL component from performing calibration operations on the analog
outputs. In order to calibrate the analog outputs, you must first unlock the component using
the AOCAL:UNLOCK message.
Refer to
Analog input calibration messages
and
Analog output calibration messages
calibration messages provided by the firmware.
Bulk transfers:
o Bulk transfers to endpoint 1 are used for analog input and output scans.
o Analog input scan data is sent through the bulk In endpoint. Analog output scan data is sent
through the bulk Out endpoint.
o The bulk in and bulk out max packet sizes are 64 bytes.
o The bulk transfer size must be a multiple of the USB maximum bulk packet size.