User Guide

RTH100 Series Temperature & Humidity Recorder
Instruction Manual
Page 7
7
Contact Differential
The procedure in the following paragraphs are for a single pen or dual pen instruments.
Refer to Fig. 6. below for mechanism detail.
With the chart plate removed, cut a segment of chart and place on to the chart clamp. Set the desired value pointer (1 or 2) to the
required value by means of the setting knob (3 or 4).
Move the actual value pen (5 or 6) until it just makes contact with the switch arm (7).
Note: The contact point can be determined by observing the LED's in the instrument door
The mains supply needs to be connected and switched on and the insulation spanner supplied must be
used (the mechanism contacts carry 12 volts).
Move the actual value pen (5 or 6) to the required deviation above the desired value pointer (1 or 2) and adjust the high contact (9
or 10) until it just makes contact with the switch arm (7) as indicated by the high alarm LED in the instrument door.
Low contact is set by moving the actual value pen (5 or 6) to the required deviation below the desired value pointer (1 or 2) and
adjusting the low contact screw (8 or 11) until it just makes contact with the switch arm (7) as indicated by the low alarm LED in the
instrument door.
Fig 6. Recorder Mechanism