TM8400B-L-00
1 November 2004
4. CONTROLS AND INDICATORS
4.1. GENERAL
All primary instrument controls and indicators are located on the front panel. The main power,
voltage select switch and main supply fuse are mounted on the rear panel exterior. Figure 4.1
identifies the front panel controls and indicators as well as some other functional items.
4.2. CONTROLS
(a) FLOW RATE: This valve regulates the flow of the sample water by controlling
the air pressure in the sample bottle. A flow rate of 30 ml/min is available with flow rate
valve at maximum (valve fully clockwise). Decreasing the flow rate allows more time for
the sample temperature to equal bath temperature before sample water enters the
conductivity cell.
(b) TANK DRAIN: This valve must be open (fully counter-clockwise) when filling or
draining the tank through the TANK DRAIN/FILL spigot; closed when filling through
top tank opening and for all other operations.
(c) CHECK HEATER: This indicator lights continuously when one of the heater lamps is
open circuit.
(d) PUMPS: This switch is normally left in the OFF position unless filling or
flushing the conductivity cell.
(e) TEMPERATURE-SET C: This six-position switch selects 18°C, 21°C, 24°C, 27°C,
30°C or 33°C bath temperatures. The bath temperature must be set within -2°C to +4°C
of room temperature.
(f) TEMPERATURE SENSOR: This three-position switch is left in the NORMAL
position except to check thermistor sensor operation when positions 1 and 2 are used.
(g) STANDARDIZE: This ten-turn vernier potentiometer (with 100 divisions-per-turn
scale and locking arm) is used with the FUNCTION switch in the READ position when
standardizing the instrument.
(h) FUNCTION: This switch has three positions. In the ZERO position, the display
indicates if the zero reference has drifted. In the READ position, the display indicates
twice the conductivity ratio of the sample to the standard. In the STANDBY position, the
first two digits of the display indicate the setting of the TEMPERATURE SET °C
switch. A change in the reading of the last four digits indicates the STANDARDIZE
control setting has changed or the electronics has drifted from the last standardization.
To Next Page
Loading...