Support Engineering Group : New DGH can for high resolution pH and temperature measurement on an ROV This page last changed on Apr 15, 2015 by tm. tDGH Can Users Guide ### - - - - - - - - DGH Can upgrade project was prioritized up by the Engineering Director in Sep. 2013 in order to remove the project from the 2014 project list and make good on an unrealized project from 2012. The original scope of work was to fit MBARI HRpH instruments to the DGH can. RS485 feature of MBARI HRpH was planned. In 2013, the requirement was added to use the new Seabird 18s digital pH instrument since this instrument was the result of a tech transfer by Thom Maughan to Seabird of the MBARI HRpH instrument and the Seabird 18s is now available as of 4Q2013 (though it is not advertised yet on the Seabird website). The Seabird 18s does not have an RS485 interface option which motivated a different engineering approach (use of custom microprocessor to aggregate the RS232 instruments and present as a single DGH module to keep the PC software simple). ## DGH Can Upgrade (tDGH) Requirements: requirements defined, then reviewed with Ed Peltzer and Dale Graves Sep 2013 ### Hardware #### Sensor Interface 4 channel analog for platinum sensor resistors (RTDs from Omega, same as existing DGH can) 4 channel digital for RS232 Seabird 18s sensors (4 pin, 12v, RS232). Ability to electrically isolate in case of pH instrument failure. #### ROV Interface RS232 Single power supply +24v, GND (+24v is more readily available on ROV per DG) ### Mechanical The existing DGH housing is corroded, a new housing is desired with 4 connectors for temperature and 4 connectors for pH and 1 connector for ROV ### Software #### DGH Can Must support maximum 1 Hz sample rate (once per second); logging at 1 Hz as well. Typically logging is at 0.5 Hz. Would like 0.2, 0.1 Hz options as well. #### PC Installer or standalone executable, must not 'clobber' shared dll's used by another program. virtual machine will be created of Ed's laptop to 'test' the lab view installer. We will do this early to gate the approach on software. Same functional and graphical features as existing software. GUI similar to what we now have in layout with graphical display of pH and "sliders" (horizontal bar graphs) for temperature. GUI should also allow for: a. Selection of any temp sensor to go with any pH sensor. b. Separate calibration constants (slope & offset) for each pH sensor. c. Separate temperature offsets for each temp sensor. ### Time and Division of Labor: Ed is the customer and supplies the requirements. Ed's laptop will need to have a virtual machine constructed to prevent the newer LabView Dll's from affecting an older program. From time to time Ed will need to log into this virtual machine so that Thom/Dale can test. Several attempts at making a VM wire tried, Ed's directory replication setup causes VMWare failure Thom to provide Dale the software def for serial comms so he can work on the Labview GUI ahead of hardware availabilty (Complete) Thom will be responsible for the project and perform the electronics design and write software/firmware for microprocessor. Thom will define serial communications protocol. (In Progress, working over Thxgiving) Jose will do the PCB layout (Complete) Indtec will do the assembly (some parts are BGA) Dale will do the PC Software / GUI (Labview to be used) Dale will update the instrument housing and spec out the external connectors ### tDGH controller bringup / hardware design verification Partial stuff, MSP430F5438A + MAX3222 + MUX + Power Converter + LEDs isolating converter consumes ~87mA with 10mA load on 3.3v JTAG connection, 14pin connector orients to edge of board, works well LEDs work UART connection to MAX3222 works GPIO connections to INST PWR Enable works Full stuff controller board received from Indtec on Dec. 4, Tom Marion built up interface board on Dec. 4 Had Jose cut/jmp to fix MAX3222, Mux lines, pull ups on Mux Dec 5. PCB Issues MUX lines not connected to processor, fixed with blue wires, fixed in rev2. FIXED v2 28 Dec 2013 no TX output on MAX3222, C1/C2 cross wired, Fixed with circuit mod. FIXED v2 Should have pullups not pull downs on serial lines for MUX - FIXED v2 Isolating RS232 not working FIXED v2 Firmware Clock subsystem, 16.777 MHz operation for SMCLK, MCLK, ACLK, Tektronix TDS2024B measures 16.89 MHz (100ns grid). 0.7% error. 115200 measures a bit over 8.67 usec per bit time, closer to 8.8 usec. Normally high signal. LEDs UART0 to 3 sending data, confirmed 115200 INST1 PWR Enable tested and working ToDo UART to Instrument connection (fix MAX3222). C1/C2 caps wired incorrectly (fixed in rev 2) DONE UART to ROV isolated connection, need to figure out why it's not working. DONE Finish hardware bringup and spin rev2 of the controller board. DONE UART ISR Test serial mux, latency, glitch, etc DONE Write test program for exercising relays on interface board DONE Write DGH module interface for temperature readings DONE Write Seabird 18s interface and driver DONE Wire up the DGH housing connectors and mount the board set and DGH module Integration test with 5 pH and max sample rate (1Hz) in test tank ### Seabird 18s setup setoutputformat= 0 0 *±vvvvv.vv\r\n pH probe voltage in mV, MBARI style output 1 ±vvvv.vv\r\n pH probe voltage in mV 2 v.vvvv\r\n pH probe voltage in SBE 18 volts cal for fast response (request, response immediate, othewise a couple seconds) setautorun=0 no autorun enter interactive mode on powerup, 1 enters tsc on powerup. If tsc is stopped via ESC the instrument re-enters tsc on power cycle. setexecuted=0 suppress <Executed/> tags 1 do not suppress setecho=0 suppress echoed characters 1 do not suppress setprompt=0 suppress 'S>' 1 do not suppress setbaud=115200 9600, 38400, 115200 setsampleperiod=1 n seconds between scans when running continuously. Each sample is comprised of an average of 8 scans. Operational commands ts <see format for output> returns a measurement in one of the above formats. tsc <see format for output> continuously samples and returns the measurement in one of the above formats. The update rate is 1Hz which is an average of 16 samples. Return to interactive mode via the ESC key. gethd getcd getec getsd getcc Electrical Voltage input 11VDC - 18VDC Current consumption 82mA at 12VDC ### DGH D5451 Module setup Setup the D5451 to 115200 baud, procedure: Wire the default pin on the D5451 to Ground, set terminal to 300 baud (8N1) with serial port connected and 12v supplied (47mA) $1WE (echo *) $1SU3108E1C2 (echo *) change terminal settings to 115200, then disconnect the Default pin from ground (leave floating) $1RS should return *3108E1C2 $1RD will take a sample, returns *-99999.99 with input floating (no thermistor) ### Serial Protocol Power All (0=off, 1=on) $1PA0<CR/LF> response 0<CR/LF> Channel 1 Power Control = 0 (Off) $1PC0<CR/LF> Response: 0<CR/LF> Channel 1 Power Control = 1 (On) $1PC1<CR/LF> Response: 1<CR/LF> Channel 1 Power Read $1PR<CR/LF> Response: 1<CR/LF> Read Block $1RB<CR/LF> read temperature sensor block (4 channels) $5RB<CR/LF> read pH sensor block (Seabird 18s) Response: *+02712.00 *+00200.00 *+00125.76 *+00347.95 Read Data $1RD<CR/LF> read tDGH channel 1 (temperature ch 1) $2RD<CR/LF> read tDGH channel 2 (temperature ch 2) $3RD<CR/LF> read tDGH channel 3 (temperature ch 3) $4RD<CR/LF> read tDGH channel 4 (temperature ch 4) $5RD<CR/LF> read tDGH channel 5 (pH sensor ch 1) $6RD<CR/LF> read tDGH channel 6 (pH sensor ch 2) $7RD<CR/LF> read tDGH channel 7 (pH sensor ch 3) $8RD<CR/LF> read tDGH channel 8 (pH sensor ch 4) $9RD<CR/LF> read tDGH channel 9 (pH sensor ch 5) Attachments: SBE 18S Commands.pdf (application/x-download) SBE18S.zip (application/zip)

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