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Related Manuals for Chell microDAQ3
Summary of Contents for Chell microDAQ3
- Page 1 Chell Instruments Ltd Folgate House Folgate Road North Walsham Norfolk NR28 0AJ ENGLAND Tel: 01692 500555 Fax: 01692 500088 microDAQ3 Pressure Sensor Acquisition System USER PROGRAMMING GUIDE info@chell.co.uk e-mail:- Visit the Chell website at: http://www.chell.co.uk 900253-1.5...
- Page 2 Chell Document No. : 900253 Issue 1.5 ECO: 5832 Date: 8 November 2023 Chell’s policy of continuously updating and improving products means that this manual may contain minor differences in specification & functionality from the actual instrument supplied.
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Page 3: Table Of Contents
2. User Command Protocol............2 2.1 Command Packet.............................2 2.2 Acknowledgement...........................2 2.3 User Commands............................2 3. Status Data Format..............6 4. microDAQ3 Communication Channels........7 4.1 TCP ................................7 4.1.1 Overview..............................7 4.1.2 Connection............................7 4.1.3 TCP Protocol ............................7 4.1.4 TCP Data Rate. -
Page 4: Introduction
1. Introduction. From power up, the microDAQ3 reads its non-volatile setup information and calibration, and after applying these settings is then ‘up and running’, reading the sensors and delivering calibrated data. Although for many applications this is enough, more demanding applications may need to control the data delivery, request data rezero operations and more. -
Page 5: User Command Protocol
Description Char/ ASCII Standby S/83 None Set all data streaming off. Reset R/82 None Request a soft device reset – microDAQ3 is reinitialised. Rezero Z/90 None Request a rezero. Span E/69 None Request a span calibration. byte = 0xab Adjust the data delivery rate for each communication channel. The... - Page 6 2 – CAN Get Status ?/63 0 : Short Return a status packet from the microDAQ3. Three main versions are 1 : With temp. available, ‘short’, ‘with temp.’ and ‘full’. Short returns status byte 2 : Full information showing current operating state only, whereas ‘full’...
- Page 7 = 1 TCP / UDP b = 2 CAN PTP Sync p/112 0 – Off Sets whether the microDAQ3 attempts to synchronise with an 1 – On external PTP Grandmaster clock on its network. Time Format q/113 0 - UTC...
- Page 8 Figure 2.2, The Available User Command Set for the microDAQ3 900253-1.5 Page 5 of 18...
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Page 9: Status Data Format
Status data is not currently supported over the CAN channel, however for TCP and UDP connections, status data may be requested from the microDAQ3 as three main forms – ‘short’, ‘full’ and ‘with temp’. The short form returns 4 bytes, the 16 bit status word delimited by the ASCII characters ">" and "<", the less significant byte is returned before the more significant. -
Page 10: Microdaq3 Communication Channels
When using the TCP/IP channel, the microDAQ3 is programmed to listen on its user defined local port number (default 101). It will respond to a connection request, connect and immediately start streaming data if it has been setup to use the TCP channel. Note that the microDAQ3 only supports a single simultaneous TCP connection. -
Page 11: Tcp Data Rate
In Windows 2000, the DWORD value TcpDelAckTicks should be set to 0 in the registry key. Also note that the TCP channel of the microDAQ3 is subject to buffering both within the unit itself (the size of the buffer depending on number of channels and data rate), and within Windows® itself. At low data rates, it is possible to receive single complete data packets, however as the data rate increases Windows®... -
Page 12: Udp
UDP channel with remote IP address and port configured in the settings. Setup requires the microDAQ3 to be given an IP address, and the network’s subnet mask - these will be the same as for the TCP - however in addition to those, UDP also needs a remote IP address and remote port number. -
Page 13: Control Via Udp
January 1970) and the second being the number of microseconds in that second. In the microDAQ3’s data streaming, the timestamps can be placed at the start of a channel cycle (ie. before channel 1’s data) or in front of every channel. This is configurable from the Timestamping page of the embedded webserver. -
Page 14: Can
4.5.2 CAN Baudrate. The microDAQ3 offers a single ‘standard’ CAN bus connection running at a selectable baudrate, the user having access to the values used for the microDAQ3’s microcontroller CAN timing registers to enable customising of sample point and jump width. -
Page 15: Can Protocol
Two separate protocols are available from the setup – either multiple or single message. For the former, the microDAQ3 is allocated a fixed message ID for each group of 4 pressure channels therefore a total of 16 sequential CAN message identifiers are required. Alternatively for a more economical use of identifiers within a system, a single message ID may be used, with all channels sent over this message sequentially. - Page 16 The single message identifier option is included to reduce the number of CAN ID’s required within a system. Data is packed into 7 byte messages, 3 channels per message with one channel identifier byte. This identifier byte is incremented for each message in the sequence, starting at 0x00 for channels 1,2 3, then 0x01 for channels 4,5,6 etc.
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Page 17: Can Data Rate
As with TCP & UDP, the available data rates are also dependant on the sensor response setting of the microDAQ3. The maximim data rate available is equal to the sensor response setting thus to achieve the maximum data rate of 400Hz sensor response must be set to ‘400Hz’, this is previously explained by Figure 4.2 in the TCP section. -
Page 18: Valve Control User Commands
Figure 4.7, Data Structure of the CAN Incoming Control Message. 5. Valve Control user commands Valved microDAQ3 variants contain an internal purge/rezero valve, the control of these valves is done via the same command protocol as with the other microDAQ commands (see previous sections above). These commands change the valve accordingly to perform a zero function or a purge function and also to simply move the shuttle valve between PURGE/CAL &...
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