The specifications of the Recording Vector Averaging Current Meter, RCM 7, are as follows:

Measuring system:

   Self balancing bridge with sequential measuring of 6 channels and solid state memory. 10-bit binaryword for each channel. The channels are:

1. Reference:

   A fixed reading to check RCM's performance and identify individual instruments.

2. Temperature:

   Standard is Low Range (-2.46 to 21.4°C). Also available are; Wide Range (-0.34 to 32.17 °C); High Range (to 36° C) and Arctic Range (-2.64 to 5.62°C in channel 4). Sensor type is Thermistor (Fenwall GB32JM19) and accuracy is ±0.05°C. Resolution is 0.1% of range selected and response time is 12 seconds (63%).

3. Conductivity: (optional)

   Sensor Type:             Inductive Cell 2994

   Ranges:                 0—74 mmho/cm (standard)

                             24 — 68 mmho/cm (on request)

                             24 — 36 mmho/cm (on request)

   Resolution:              0.1% of range

   Calibration Accuracy. ±0.025 mmho/cm

4. Pressure: (optional)

   Sensor Type:             Bourdon tube driving potentiometer

   Ranges:                 100,200,500,1000,3000and9000 PSI

                             0-3000 PSI is standard

                             0-9000 PSI only available for RCM8

   Accuracy:                ±1 % of range

   Resolution:              0.1%of range

5.and 6. Current speed and direction:

   Vector Averaging; No. of rotor revolutions and direction is sampled every 12 seconds and broken up into North and East components. Successive components are added and recorded as speed and direction. For longer recording intervals than 10 minutes, speed and direction is sampled 1/50 of recording interval.

 Direction:

   Sensor Type:           Magnetic compass with needle clamped onto potentiometer ring

    Resolution:          0.35°

    Accuracy:              ±5° forspeeds from 5to 100cm/sec, ±7.5° for current speeds 2.5 to 5 and 100 to 200 cm/sec

Speed:

   Sensor Type:      Rotor with magnetic coupling

   Range:               2 to 250 cm/sec

   Accuracy:            ±1 cm/sec or ±2% of actual speed whichever is greater

   Starting Velocity:      2 cm/sec

 

Clock:   

   Type:             Quartz Crystal

   Accuracy:            Better than ±2 sec/day within O to20°C

   Recording Intervals:      0.5,1,2,5,10,20,30,60 or 120 min.

   External Triggering: A 6V pulse to terminal activates instrument.

 

Recording system:

   Type:                Data Storing Unit 2990

   Coding:              PDC-4

   Storage Capacity:      Maximum 10.900 records of all channels

                        (i.e. 75 days with 10 min.interval).

 

 Telemetry:           

   Acoustically:           Acoustic carrier keyed on and off

   Frequency:        16.384KHz ±5Hz.

   Detection Range:      Up to 2000m with unit 3079

Power:           

   Battery:            9V, non-magnetic: 63 x 50 x 80mm

   Capacity:            4Ah (sufficient for 10.900 records )

External Materials

   Pressure Case:      CuNiSi alloy (OSNISIL)and stainless acid proof steel. Epoxy coated

   Other Metal Parts      Nickel plated bronze and stainless acid proof steel. Epoxy coated

Mooring:

   Spindle for 15mm max. diameter rope. Gimbal mounting permits 27° deviation between spindle and instrument. Spindle: breaking load 4-OOOkg.

                              RCM7        RCM8

Depth Capability:             2000m      8000m

Net Weight (kg) in:       air      water      air      water

   Recording Unit:          13.6      8.8         15.2      10.9

   Vane Assembly:         12.2      9.5         14.1      11.8

 

Dimensions (mm):      

   Recording Unit:       495x128           520x128

   Vane Assembly:                   485 x 500

   Overall Size:              540 height x 865 length

Gross Weight (kg):

   Recording Unit:              18.5        20.5

   Vane Assembly:             20.0        22.0

 

Packing:                   Plywood cases

   Recording Unit:          190 x 250 x 600mm

   Vane Assembly:         140 x 520 x 770mm

Spares:

   A set of recommended spares is delivered free of charge with each instrument (rotor, bearings, 0-rings etc)