Rototherm RTH TEMPERATURE HUMIDITY RECORDER User Manual

RTH100 Series

Temperature & Humidity Recorder

& Recorder/Controllers

Instruction Manual

British Rototherm Co. Ltd.,
Kenfig Industrial Estate, Margam,
Port Talbot, SA13 2PW,
United Kingdom

Telephone: [phone]
Facsimile: [phone]/741 275
E-mail: [e-mail]
We Site: www.rototherm.co.uk

Issue 12/03

RTH100 Series Temperature & Humidity Recorder

Instruction Manual

Page 1

1

Contents

Page

Introduction

Operation 1
Control Circuit 1
Recorder Specification 2

Installation

Mounting the Recorder 3

Commissioning

Access to Instrument 5
Electrical Connections 5
Fitting a Chart 6
Inking System 6
Contact Differential 7
Accuracy Adjustments 8
Zero Adjustment 8

Maintenance 8

Spare Parts 8

Introduction

The RTH100 Series of temperature and humidity circular chart recorders uses the proven design combination of bimetallic coil and
hygroscopic membrane for the direct measurement of temperature and humidity.

Air is drawn through the instrument and over the sensing elements by an electrically driven fan. Expansion, or contraction, of the
bimetallic coil, due to temperature change causes pen movement by direct linkage. Similarly, a change in humidity causes exten­sion or contraction of the hygroscopic membrane and direct linkage again causes movement of the second pen.

The RTH100 Series range comprises of recorders and recorder controllers as either temperature, humidity or combination instru­ments. Controllers can be supplied with up to four separate alarm contacts set by reference to a setting pointer adjustable over the
full chart range. Each alarm contact operates and independent output relay providing single pole changeover, voltage free, output
contacts. High and low alarm points for temperature and humidity are indicated by illumination of red LED’s positioned above the
viewing window in the upper part of the recorder door. All control instruments are fitted with an audible alarm indication of set points,
silenced in operation by pressing the switch located

Fig 1. Operation - Control / Alarm Circuit

RTH100 Series Temperature & Humidity Recorder

Instruction Manual

Page 2

2

Specifications

Range

Temperature: 0º to 40º or 20º to 100ºF
Humidity: 20 to 100% RH (see notes)

Measuring System
Temperature: Bi-metallic coil

Humidity: Hygroscopic membrane

Accuracy

Temperature: ±1% of the chart range
Humidity: ±2% within the limits 30 to 85% RH and 1º to 40ºC

Chart

Diameter: 240 mm diameter
Drive: Electrical motor

24 hour or 7 day rotation as standard 3 hour, 6 hour, 12 hour and 28 day on application

Outputs and Set Points

Number of set points: Up to 4 set point adjustment by setting pointer against chart graduation
Number of output relays: Up to 4
Relay contacts: Double pole changeover
Switched voltage max.: 30Vdc/277Vac
Switched current max.: 10A
Switched load max.: 150W/1660VA
Insulation, contact to earth: 2kV

Power Supplies

Voltage requirements: 110V or 230V 50/60 Hz
Power requirements: <20VA
Insulation, contact to earth: 2kV

Environmental Data

Storage temperature limits:
Temperature instruments: -10º to +50ºC
Temperature/humidity inst.: 0º to 40ºC

Storage humidity limits
Temperature instruments: 0 to 90%RH
Temperature/humidity inst.: 20 to 85% RH

Casing Glass filled resin case with lockable hinged door with perspex window (polycarbonate to

special order)

Mounting

Ambient sampling Wall or flush panel or portable*
Remote sampling Wall

Note When panel mounting, a suitable air circulation must be provided to the duct intake and the inlet and outlet ports must not be restricted.

* Free standing portable version available (ambient sampling type only)

Weight 6.5 Kg approx.
Sampling Type Total sampling line length is restricted to 1 metre max (20mm OD)

Where the temperature difference between sample air and case exceeds ±5ºC then the sample line must
be thermally insulated

Should the RH go above 85% RH it is possible that water droplets may form on the element. This may
have a temporary or permanent affect on the calibration.