Campbell SR50AH User manual

SR50AH
Sonic Ranging Sensor
Heater Option
Instruction Manual
Issued 26.8.08
Copyright ©2008 Campbell Scientific (Canada) Corp.
Printed under licence by Campbell Scientific Ltd.
CSL 795

Guarantee
This equipment is guaranteed against defects in materials and
workmanship. This guarantee applies for twelve months from date of
delivery. We will repair or replace products which prove to be defective
during the guarantee period provided they are returned to us prepaid. The
guarantee will not apply to:
•Equipment which has been modified or altered in any way without the
written permission of Campbell Scientific
•Batteries
•Any product which has been subjected to misuse, neglect, acts of God
or damage in transit.
Campbell Scientific will return guaranteed equipment by surface carrier
prepaid. Campbell Scientific will not reimburse the claimant for costs
incurred in removing and/or reinstalling equipment. This guarantee and the
Company’s obligation thereunder is in lieu of all other guarantees,
expressed or implied, including those of suitability and fitness for a
particular purpose. Campbell Scientific is not liable for consequential
damage.
Please inform us before returning equipment and obtain a Repair
Reference Number whether the repair is under guarantee or not. Please
state the faults as clearly as possible, and if the product is out of the
guarantee period it should be accompanied by a purchase order.
Quotations for repairs can be given on request.
When returning equipment, the Repair Reference Number must be clearly
marked on the outside of the package.
Note that goods sent air freight are subject to Customs clearance fees
which Campbell Scientific will charge to customers. In many cases, these
charges are greater than the cost of the repair.
Campbell Scientific Ltd,
Campbell Park, 80 Hathern Road,
Shepshed, Loughborough, LE12 9GX, UK
Tel: [phone]
Fax: [phone]
Email: [email protected]
www.campbellsci.co.uk

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Contents
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1. Heater Introduction .....................................................1
2. Specifications..............................................................1
3. Maintenance.................................................................2
Figures
1. SR50AH Heater option...............................................................................2
2. Complete transducer assembly with power connection..............................4

1
SR50AH Sonic Ranging Sensor Heater
Option
This manual describes the optional heater for the SR50A sensor. It is provided as an addendum
to the SR50A manual which should be referred to for general operating instructions.
1 Heater Introduction
The heater option on the SR50AH is intended for installations where rime ice is
problematic. The heater will help to prevent the ice from forming on the transducer,
which can impair proper operation of the sensor.
The heater option is easily identifiable as the transducer housing contains a cable port
for the heater supply cable.
For battery operated solar powered sites it is recommended that the power to the
heater be turned off when icing conditions are not occurring to reduce power
requirements. The heater power must be turned off when operating at temperatures of
25°C or more.
2 Specifications
Heater Resistance: 75 Ohms
Nominal Operating Voltage 12 Volts (AC or DC) Note1
Maximum Rated Wattage: 3 Watts
Maximum Rated Voltage: 15 Volts (AC or DC)
Maximum Operating Temperature: 25°CNote2
2.1 Heating Cable Requirements
Type: 2 conductor (twisted pair), Shielded
Diameter: 4-6mm (0.16 - 0.24 inches)
Recommended Gauge: 22 AWG for lengths less than 30 metres (100 feet)
1: It is important to use a properly conditioned low noise power source.
A noisy power source or use of unscreened cable may affect operation
of the sensor.
NOTE

SR50AH Sonic Ranging Sensor Heater Option
2
2: It is recommended that some form of control be used to turn the
heater power off at warmer temperatures. Damage to the sensor may
result from operation at elevated temperatures.
Figure 1 SR50AH Heater option
3 Maintenance
The same maintenance procedures apply to the SR50AH as the regular SR50A
sensor. Please refer to the SR50A manual for maintenance information.
The transducer and desiccant replacement is slightly different for the SR50AH as it is
for the SR50A. When ordering replacement transducers ensure that the SR50AH
part# C2370 is ordered.
The procedure to disassemble the SR50AH for desiccant replacement or transducer
replacement is as follows:
1. Remove the 6 slotted screws on the outermost hole pattern.
2. Separate the housing from the sensor body and disconnect the connector from
the transducer to the main sensor body.
NOTE
Cable port for heater option

Instruction Manual
3
3. To replace the desiccant remove the desiccant holder plate with the Philips 4-40
screw. Cutting the tie strap will allow the old packets to be removed for
replacement. During reassembly ensure that the desiccant does not come in
contact with the metal backing of the transducer. If only the desiccant is being
inspected or replaced, step 4 and 5 are not required. Steps 4 to 6 are required to
replace the transducer only.
4. Your transducer kit comes with a replacement for the o-ring that seats between
the main sensor body and the plastic transducer housing. Ensure that the new
o-ring is used when reassembled.
5. Remove the 3 screws from the innermost hole pattern as shown.

SR50AH Sonic Ranging Sensor Heater Option
4
1. Replace the transducer assembly and the second o-ring that seats under the
transducer assembly.
2. Reassemble the sensor in the reverse order. Please observe the orientation of the
parts, wiring and desiccant.
Figure 2 Complete transducer assembly with power connection

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