MCC 118
Voltage Measurement DAQ HAT for Raspberry Pi
The MCC 118 is a 12-bit, high-speed 8-channel voltage measurement DAQ HAT. The
MCC 118 is shown here connected to a Raspberry Pi (not included).
Overview
The MCC 118 is a voltage HAT (Hardware Attached on Top) board designed for use
with Raspberry Pi, the most popular single-board computer on the market today.
A HAT is an add-on board with a 40W GPIO (general purpose input/output) connector that conforms to the Raspberry Pi HAT specification.
The MCC 118 HAT provides eight single-ended (SE) analog inputs for voltage
measurements. Up to eight MCC HATs can be stacked onto one Raspberry Pi.
®
Features
• Eight 12-bit voltage inputs
• 100 kS/s max sample rate
(320 kS/s aggregate for stacked
boards)
• ±10 V input range
• Onboard sample buffers allow
high-speed acquisition
• External scan clock I/O
• External digital trigger input
• Screw terminal connections
• Stack up to eight MCC HATs
onto a single Raspberry Pi
Software
• MCC DAQ HAT Library;
available on GitHub
Supported Operating Systems
• Linux®/Raspbian
Programming API
• C, C++, Python
Raspberry Pi Interface
The MCC 118 header plugs into the 40-pin
general purpose I/O (GPIO) connector on a
user-supplied Raspberry Pi. The MCC 118
was tested for use with all Raspberry Pi
models with the 40-pin GPIO connector.
HAT configuration
HAT configuration parameters are stored
in an on-board EEPROM that allows the
Raspberry Pi to automatically set up the
GPIO pins when the HAT is connected.
Stackable HATs
Up to eight MCC HAT boards can be
stacked onto a single Raspberry Pi. Multiple boards can be synchronized using
external clock and trigger input options.
Users can mix and match MCC HAT
models in the stack.
Analog Input
The MCC 118 provides eight 12-bit SE
analog inputs. The analog input range is
fixed at ±10 V.
Sample Rates
• Single-board: max throughput is
100 kS/s.
• Stacked boards: max throughput is
320 kS/s aggregate1.
External Scan Clock
A bidirectional clock I/O pin lets users
pace operations with an external clock
signal or with the board’s internal scan
clock. Use software to set the direction.
Digital Trigger
The external digital trigger input is
software-configurable for rising or falling
edge, or high or low level.
Power
The MCC 118 is powered with 3.3 V
provided by the Raspberry Pi through the
GPIO header connector.
1 Rate achieved using a Raspberry Pi 3.
MCC DAQ HAT Library
The open-source MCC DAQ HAT Library
of commands in C/C++ and Python
allows users to develop applications on
the Raspberry Pi using Linux.
The library is available to download from
GitHub. Comprehensive API and hard-
ware documentation is available.
The MCC DAQ HAT Library supports
operation with multiple MCC DAQ HATs
running concurrently.
Console-based and user interface (UI)
example programs are available for each
API.
Measurement Computing (508) 946-5100
Measurement Computing (508) 946-5100
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MCC 118
Screw Terminals
Microcontroller
with
12-bit ADC
Raspberry Pi
Header
Scan Clock
Digital Trigger
I2C
SPI
+3.3 V
Analog
3.0 V
Reference
Input
Conditioning
Board
Address
Matching
HAT
EEPROM
Block Diagram
OEM Version
The MCC 118-OEM is designed with (unpopulated) header
connectors instead of screw terminals, and is functionally
equivalent to the standard version. The MCC 118-OEM
accepts 1×6 and 1×10 0.1 in. spacing header connectors.
Stackable
Connect up to eight MCC DAQ HATs onto a single
Raspberry Pi. Onboard jumpers identify each board in the
stack. Use an external clock and connect the trigger inputs
to synchronize the acquisition.
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MCC 118
Example Programs
MCC DAQ HAT Examples
The MCC DAQ HAT Library includes example programs
developed in C/C++ and Python that users can run to become
familiar with the DAQ HAT library and boards; source code is
included.
Console-Based (C/C++ and Python)
Console-based examples are provided that demonstrate how to
perform continuous and finite scans, trigger an acquisition, and
synchronously acquire data from multiple DAQ HATs (source
included). The continuous_scan example is shown here.
Display the value of each input channel in a terminal window
User Interface
Example programs featuring a user interface are provided in
different formats. Examples of each are shown here.
DataLogger (C/C++)
The datalogger example shows how to acquire data from the
MCC 118, display the data on a strip chart, and log the data to
a CSV file. This example can be run from the terminal.
Web Server (Python)
The web server example lets users configure acquisition options
and view acquired data from a browser window. This example
is written for Python (source included).
Configure options and view strip chart data from your browser
IFTTT Applet (Python)
IFTTT (If This Then That) is a free web-based service that interacts with apps and hardware to automate various functions. The
IFTTT DAQ HAT example reads two MCC 118 channels at regular
intervals, and writes the data to a Google Sheets spreadsheet.
Users can remotely monitor the spreadsheet from Google Drive.
An IFTTT account is required. This example is written for Python
(source included).
Configure options, plot data on a strip chart, and log data to a file
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View logged data on a Google Sheets spreadsheet from your browser
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MCC 118
Specifications and Ordering
Specifications
All specifications are subject to change without notice.
Typical for 25 ˚C unless otherwise specified.
Analog Input
A/D converter type: Successive approximation
ADC resolution: 12 bits
Number of channels: 8 single-ended
Input voltage range: ±10 V
Absolute maximum input voltage
CHx relative to GND: ±25 V max (power on or power off)
Input impedance: 1 MΩ (power on or power off)
Input bias current
10 V input: –12 µA
0 V input: 2 µA
–10 V input: 12 µA
Monotonicity: Guaranteed
Input bandwidth, small signal (–3 dB): 150 kHz
Maximum working voltage
Input range relative to AGND: ±10.1 V max
Crosstalk (adjacent channels, DC to 10 kHz): –75 dB
Input coupling: DC
Recommended warm-up time: 1 minute min
Sample rate, hardware paced
Internal scan clock: 0.004 S/s to 100 kS/s, software-selectable
External scan clock: 100 kS/s max
Sampling mode: 1 A/D conversion for each configured channel per clock
Conversion time, per channel: 8 µs
Scan clock source
Internal scan clock
External scan clock input on terminal CLK
Channel queue: Up to eight unique, ascending channels
Throughput, Raspberry Pi® 2 / 3 / 4
Single board: 100 kS/s max
Multiple boards: Up to 320 kS/s aggregate*
Throughput, Raspberry Pi A+ / B+
Single board: Up to 100 kS/s*
Multiple boards: Up to 100 kS/s aggregate*
* When using multiple boards, throughput depends on the load on the Raspberry Pi
processor. The highest throughput may be achieved by using a Raspberry Pi 3 B+.
Accuracy
Analog Input DC Voltage Measurement Accuracy
Range: ±10 V
Gain error (% of reading): 0.098 max
Offset error: 11 mV max
Absolute accuracy at full scale: 20.8 mV
Gain temperature coefficient (% reading/°C): 0.016
Offset temperature coefficient (mV/°C): 0.87
Noise Performance
For peak to peak noise distribution, the input channel is connected to AGND at the
input terminal block, and 12,000 samples are acquired at the maximum throughput.
Range: ±10 V
Counts: 5
LSBrms: 0.76
External Digital Trigger
Trigger source: TRIG input
Trigger mode: Software-selectable for rising or falling edge, or high or low level
Trigger latency:
Internal scan clock: 1 µs max
External scan clock: 1 µs + 1 scan clock cycle max
Trigger pulse width: 125 ns min
Input type: Schmitt trigger, weak pull-down to ground (approximately 10 K)
Input high voltage threshold: 2.64 V min
Input low voltage threshold: 0.66 V max
Input voltage limits: 5.5 V absolute max, –0.5 V absolute min,
0 V recommended min
External Scan Clock Input/Output
Terminal name: CLK
Terminal types: Bidirectional, defaults to input when not sampling analog channels
Direction (software-selectable):
Output: Outputs internal scan clock, active on rising edge
Input: Receives scan clock from external source, active on rising edge
Input clock rate: 100 kHz max
Clock pulse width: 400 ns min
Input type: Schmitt trigger, weak pull-down to ground (approximately 10 K),
protected with a 150 Ω series resistor
Input high voltage threshold: 2.64 V min
Input low voltage threshold: 0.66 V max
Input voltage limits: 5.5 V absolute max, –0.5 V absolute min, 0 V recom-
mended min
Output high voltage: 3.0 V min (IOH = –50 µA), 2.65 V min (IOH = –3 mA)
Output low voltage: 0.1 V max (IOL = 50 µA), 0.8 V max (IOL = 3 mA)
Output current: ±3 mA max
Memory
Data FIFO: 7 K (7,168) analog input samples
Non-volatile memory: 4 KB (ID and calibration storage, no user-modifiable
memory)
Power
Supply current, 3.3 V supply:
Typical: 35 mA
Maximum: 55 mA
Interface
Raspberry Pi GPIO pins used:
GPIO 8, GPIO 9, GPIO 10, GPIO 11 (SPI interface)
ID_SD, ID_SC (ID EEPROM)
GPIO 12, GPIO 13, GPIO 26 (Board address)
Data interface type: SPI slave device, CE0 chip select
SPI mode: 1
SPI clock rate: 10 MHz, max
Environment
Operating temperature: 0 °C to 55 °C
Storage temperature: –40 ˚C to 85 °C max
Relative humidity: 0% to 90% non-condensing
Mechanical
Dimensions (L × W × H): 65 × 56.5 × 12 mm (2.56 × 2.22 × 0.47 in.) max
Order Information
Hardware
Part No. Description
MCC 118 12-bit, 8-channel voltage measurement DAQ HAT.
MCC 118-OEM 12-bit, 8-channel voltage measurement DAQ HAT with
Measurement Computing (508) 946-5100
May 2020. Rev 6
DS-MCC-118 © Measurement Computing Corporation
Raspberry Pi model with the 40-pin GPIO connector
required.
(unpopulated) header connectors instead of screw
terminals. Raspberry Pi model with the 40-pin GPIO
connector required.
Software
Part No. Description
MCC DAQ
HAT Library
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Open-source library for developing applications in C, C++,
and Python on Linux for MCC DAQ HAT hardware.
Available for download on GitHub at https://github.com/
mccdaq/daqhats.
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