The S2K controls the following functions:
1. A 3-way solenoid valve: A DIP switch is used to set the
amount of time the sample is to be exposed to the sensor.
The rest of the time the sensor is exposed to clean air.
2. An external pump control timer which sets the on-off time
of the pump. The purpose of the external pump is to transport
the sample in larger quantities which shortens the transport
time. Additionally, it is easier to draw a controlled amount
of sample to be conditioned before exposing it to the sensor.
The timer turns the pump on only as needed which prolongs
the pump life and reduces pump maintenance.
3. A smaller, internal pump is on constantly to flow either
sample or clean air to the sensor. There are three timers
required to implement the complete cycle as shown in Fig.
1. External pump delay: This is the time delay from the beginning
of the cycle before the external pump is activated. During
this time, the external pump is off. The timer can be set
from 0-255 minutes, with a resolution of 1 minute.
2. External Pump Lead Time: This is the amount of time the
external pump is "ON", before the solenoid valve
is switched to let the sample into the sensor chamber. The
timer can be set from 0-2550 seconds, with a resolution of
3. This is the amount of time the solenoid valve is activated
to allow sample flow into the sensor chamber. The timer can
be set from 0-2550 seconds, with a resolution of 10 seconds.
Each timer is set by an eight position DIP switch with
the following count values:
1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 = 255. This means that
position one of the DIP switch has a value of "1"
while position 8 has a value of "128". The time
which is set for the timer is calculated by taking the count
value and multiplying it by the resolution of the timer.
A time of zero is achieved by having all of the switches
in the open position.
There is a micro-switch which activates a relay contact
if there is a failure of the flow into the sensor chamber.
A calibration switch with an LED indicator allows the user
to perform standard calibration functions on the sensors.
The S2K housing is designed to be used with standard IST
4-20 IQ sensor modules but other sensor modules (such as
the SM95) can be used also.
The S2K sampling system can be configured with a variety
of options. Fig. 3 illustrates the two-stage sampling system.
Figure 4 shows a complete system with a sample diluting
assembly. IST will assemble the system to meet application
|345(H) x 292(W) x 127(D) mm; (13.6"H
x 11.5"W x 5.0"D).
|5.5 Kg (12 Lbs).
|Timer controller function:
|See description above.
||SPST Normally Open, 5 amp resistive. 220
VAC max. 1/8 HP motor.
Three relays are provided for the following:
1. No flow into sensor chamber.
2. External pump activation Relay.
3. Solenoid valve.
|Oscillating AC Diaphragm. Replaceable.
|Dwyer Instrument, Inc. RMA-13-SSV. Ranges
|110/220 VAC, 50/60 Hz.
|-20°C to 50°C.