Description

The driver, device and Channel Access EPICS input-output controller for DI-245 Thermocouple and Voltage Data Acquisition System by DATAQ Instruments. The link to the DI-245 manual and the website .

Driver

Four-channel USB Voltage and Thermocouple DAQ driver, Resolution: 14-bit Sampleling rate: 8000 Hz max Range: +/- 50 V to +/- 10 mV, in 3 steps per decade (1,2.5,5) build in cold junction compensation (CJC) for thermocouples

Reference: DI-245 Communication Protocol www.dataq.com/resources/pdfs/support_articles/DI-245-protocol.pdf

COM Port Communication Settings: Baud rate: 115200, Data bits: 8, Stop bits: 1, Parity: none

Installing the DI-245 driver package and connecting DI-245 hardware to the host computer’s USB port results in a COM port being hooked by the operating system and assigned to the DI-245 device.

Multiple DI-245 devices may be connected to the same PC without additional driver installations, which results in a unique COM port number assignment to each by the operating system.

The DI-245 employs a simple ASCII character command set that allows complete control of the instrument.

Long commands and arguments (longer than two characters) are separated by a space character (0x20), and each long command string must be terminated with a carriage return character (x0D). Long commands do not echo until the 0x0D character is received.

Short commands (2 characters or less) are preceded with a null character (0x00), which is not echoed, but each command character is echoed as it is sent.

<0x00>command<(0x20)<argument1>(0x20)<agrument2>(0x0D)>

For example, the command “0A1” generates the following response: “A1 2450”

Commands: “0A1”

Returns device name: “2450” “chn 0 5120r” Enable analog channel 0 to measure an N type TC as the first scan list member “chn 1 514r” Enable analog channel 2 to measure +/-100 mV as the second scan list member “chn 2 3331r” Enable analog channel 3 to measure +/-1 V as the third scan list member “xrate 1871 10r” Burst rate is 10 Hz, sampling frequency SF=79, averaging frequency AF=7, SF+AF*256 = 79+7*256 = 1971, burst rate B = 8000/((SF+1)*(AF+3))

“0S1” Start the scanning processes, causes the DI-245 to respond with a continuous binary stream of one 16-bit signed integers per enabled measurement. The stream sequence repeats until data acquisition is halted by the stop command. “0S0” Stop the scanning processes

Start by importing dataq DI-245.

import dataq_di_245