The Series 33 range of recorders and recorder controllers may be used with thermocouple, resistance thermometer element, strain gauge or potentiometric pressure transducer, or any transducer producing a dc current or a voltage signal. Recorders and recorder controllers can be fitted with a digital display if required.

OPERATION

A high-quality dc servo motor is utilized for the prime mover, and this is coupled to the outlet spindle and feedback potentiometer by a precision gear train, adjusted for minimum backlash. The feedback potentiometer is a conductive plastics device, which does not require maintenance. The output spindle operates the pen/index of the mechanism.

Alarms, electrical re-transmission, electric contact control or an auxiliary power supply are available as options.

ALARMS

The operation of alarms (if fitted) is electronic, and is independent of the pen. Either absolute or deviation alarms are available. Absolute alarms can be set to any value within the range of the instrument: deviation alarms operate with relation to the desired value, and can be set either above it (positive deviation) or below it (negative deviation).

The alarms are set by adjusting a potentiometer against the scale. A push button, which will drive the pen to the alarm trip point, is included in each circuit to enable the setting to be checked. On instruments with deviation alarms the push button will drive the pen to the set deviation from the mid chart, regardless of the control setting. Because the relays are normally energised when the measured conditioned is out-of-alarm (fail safe), it is necessary to specify, at the time of ordering, which of the alarms is to be set "high" or "low". Whatever the setting on the scale, an alarm state that is reached on a rise in value is termed "high" and that on a fall in value "low".

RECORDER

Available as a single pen, two pen or three pen model, this potentiometric disc chart recorder will produce a permanent record of the value of the measured variable.

With a two-pen recorder the measuring element for the second pen can be a Bourdon or diaphragm pressure measuring element.

A three-position operations pen can be supplied, provided that no pen lift is required and that no alarms are required on the second system, if fitted.

PENS

Fitted to the pen arms are disposable fiber tipped pens which are readily replaced without mess. Single pen recorders and the first pen of two and three pen recorders trace in red ink, the second pen in blue, the third in green.

CHARTS AND CHART DRIVE

Charts are supplied normally with the minimum measuring value at the center, although other styles are available. Standard chart duration's are one revolution every 24 hours or 7 days with special duration's available on request. A pen lift is fitted to ease chart changing.

PNEUMATIC CONTROL

Series 33 recorders may be specified with pneumatic control. Single or two pen recorders may be specified, single pen may be specified with full three term control Proportional (P) Integral (1) or Derivative (D) in combination of P, P+I, P+D or P+I+D. For full pneumatic specification see Data Sheet RPC-96.

ELECTRIC CONTROL OPTIONS