Xylem WS755 IMPROVED WASTEWATER/STORMWATER SAMPLER - Manual (Page 9)

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VIII. Mixed Sampling, Composite and Discrete Sampler
The WS755 Sampler can be configured as both a composite and discrete sampler at the
same time since each pump has a separate Size control. Set one pump’s size setting to the
desired composite sample size and the other to “Full”.
Again, the Start Delay timer begins when the sampler is trigger by the Rain and Water
Sensors and the first sample is taken when the timer expires. If the Delay control is set to
zero, sampling begins immediately. The Status LED blinks every 2 seconds while the delay
timer and the pumps are running and remains lit constantly once both of the sample bottles
have been filled. At the end of each sample, the pumps reverse for 15 seconds.
X. External Trigger Mode
When the Sample Interval control is set to the “External Trigger” position, the sampler can
be triggered externally by inputs from either the Trigger In jacks or the Rain Sensor input.
This mode is useful in applications where sampling occurs based on readings from a
process controller, SCADA system, flow monitor, auto-dumping rain gauge or other remote
monitoring devices.
Using the Rain Sensor as a trigger source:
This mode is normally used with an auto-dumping rain gauge that empties itself every 24
hours. Set the Sample Interval control to External Trigger. Set each pumps Size control
based on desired composite sample size or set to Full for a discrete sample.
The sampler will be triggered when both the Rain and Water Sensors detect moisture. If the
Water Sensor is not needed, use one of the shorting plugs supplied with the sampler to
defeat it by plugging it into the Water Sensor input jack. Place the Rain Sensor at the
desired height in the rain gauge. When the Rain Sensor detects moisture, the sampler will
start.
Once triggered by the Rain Sensor, the Start Delay timer begins running and the Status
LED begins blinking every 2 seconds. When the timer expires, the pumps take a sample
based on their individual Size settings. When the samples are complete, the pumps reverse
for 15 seconds, then stop. The sampler cannot be re-triggered until the rain gauge empties
itself and the Rain Sensor goes dry. The next time the sensor detects moisture, the Start
Delay timer will start over again and another sample will be taken when it expires.