1. The Instrumentation Unit (IU) of the Calibration Unit (CU)
Status 10/02/2017
Pascale Keller for the CPPM group
Calibration meeting, 10/02/2017

2. The Instrumentation Unit (IU) for the CU
Reminders :
Inductive Instrumentation Unit directly inspired of the Albatross line (but Albatross is not linked with a cable to an infrastructure, data transfert via acoustic modem)
The IU is composed by one inductive Instrumentation Line (IL) and one titanium Instrumentation Base container (IB) + one dead weight
The instruments are autonomous in terms of energy using internal batteries
The IU is recoverable in order to change the batteries and to calibrate some of the instruments that need recalibration periodically (about once every 2 years)
The IU will be connected to the electric interlink cable with a ROV via the IB wet matable connector

3. The Instrumentation Unit (IU) for the CU
Schematic diagram :

4. IU : status on inductive modem system (Seabird)
Test bench operationnal in CPPM :
IMM (inductive modem) linked to a PC via RS232 (simulates the CB of CU)
IMM connected on a 50 cm wire (simulates the interlink cable to CB) via an inductive core (simulates the Inductive Cable Coupler)
Simul. Inductive cable
Simul. Inductive cable coupler
Simul. IU Manager (CB)
IMM : inductive modem
UIMM serial/inductive adapter : to interface Aquadopp currentmeter

5. status on instruments & inductive devices
Inductive devices status :
IMM (Inductive Modem) : 2 in CPPM
ICC (Inductive Cable Coupler) : to be ordered
UIMM (serial/inductive adapter) to interface Aquadopp : 1 in CPPM
SBE44 (serial/inductive adapter+battery) to interface miniSVS : to be ordered
300m MSI inductive cable : in CPPM => will be probably replaced by
One 200m inductive cable
Instruments status :
CTD Seabird : 1 inductive native in CPPM, 2 non inductive native in CPPM
Currentmeter Aquadopp : 3 non inductive native in CPPM (need to be interfaced via UIMM)
Sound velocimeter mini SVS Valeport : 1 in CPPM
(need to be interfaced via SBE44)

6. status on IU/CB communication
The IMM communicates via RS232 and it is preferred to be adapted into another communication standard in order to trnasmit data over electric cable from 50 to 100 m (or more) length
The possible choices were : ethernet, RS485 and RS422
We performed tests with RS485 and RS422 :
RS485 is quite touchy to adjust with ending resistors and needs to manage the RTS/CTS logic signals
RS422 tests were successful and it is more simple to be operated but need 4 wires because it is a full duplex communication
RS422 Test setup :
status on IU/CB communication

7. status on IU/CB communication
RS422 Test setup :
Conversion RS232/422 board : 50m electric test cable
status on IU/CB communication
We performed tests using a 50m submarine electric cable (lent by INSU) similar to the on that is foreseen for the french site
The tests have been performed from 9600 bauds to bauds with success
Data transfert directly between 2 PC via 50m cable
Communication between IMM and PC via 50m cable

8. status on IU/CB communication
Conversion RS232/422 Electronics schematics proposal :
Estimated power need :
 The IU will be linked to the Calibration Base of the CU via one 50 m electric serial cable using RS422 serial communication for the data transfert :
4 electrical points for the RS422 link
2 electrical points for the 12V power (supplied by CB)
Consultation of the submarine cable have been launched (Macartney/ODI)
 Still waiting for proposals

9. Electronics container of the IU
Electronics specifications : - manage the inductive modem
- manage the serial communication with CB
Design of electronics container under going
Design of electronics board under going

10. status on mechanics Global mechanics specifications :
Essential elements of subsystem line : buoy , instruments (devices), anchor (design in progress).
Deployment and recovery each 2 years with optimal safety
Anchor functions :
Deadweight (in steel materials) for anchorage (it is possible to add additionnal mass)
The titanium frame integrate :
the release system
the connexion/deconnexion tools for the junction to the CB at the IU
a survey and cleaning port
a titanium container ‘IB’
A sling with four legs to connect to the instrumented cable
Compacity of anchor (link between the deadweight and titanium frame) during recovery and deployment phasis.

11. status on mechanics

12. status on mechanics Design of titanium frame currently under going
Design of electronics container under going

13. status on mechanics / operations
 Cf Alain’s talk
The DU deployment procedures have to be adapted for the IU
The basic idea is that the IU will be deposed to the seabed from the surface boat using the winch with absolute positioning
Because of their fragility, the instruments will be attached on the mooring line one by one on the boat while the line will descend (idem for the IU recovery)
After deployment, the electric interlink cable will be connected to the IB with a ROV via the wet matable connector.
For the recovery, a ROV will deconnect the interlink cable from the IB and the acoustic released that will be activated in order the IU to go up thanks to adapted syntactic foams buoy
=>  Procedures of deployment and recovery of the French site IU have been studied
=> technical note under going