
Pyxis ST-601
Operation Manual
8
3
Quick 4-20mA Start
Follow the wiring table below to connect the ST-601 probe to a receiving controller.
Wire Color
Designation
Red
24 V +
Black
Power Ground
White
4-20 mA +
Green
4-20 mA -, internally connected to power ground
Blue
RS-485 A
Yellow
RS-485 B
Clear
Shield, Solution ground
*
Note
*: The 24V power ground and the 4-20 mA- return are internally connected. If insufficient wattage is
available from the connected controller (ie. 1.5-1.6W), Pyxis recommends the PowerPACK Series Auxiliary Power &
Communication Box highlighted in the Accessories section of this manual.
If the 24V power ground terminal and the negative 4-20 mA terminal in the controller are internally
connected (non-isolated 4-20mA input), it is unnecessary to connect the 4-20 mA - (green wire) to
the 4-20 mA negative terminal in the controller. If a separate DC power supplier other than that
from the controller is used, make sure that the output from the power supply is rated for 22-26 VDC
@ 65mA. Detailed wiring diagrams for common controllers are available from
4
Calibration and Diagnosis
The ST-601 probe can be calibrated in a two-point (zero + slope) procedure using a deionized water sample
and a standard solution containing a known ClO2 concentration. For ST-601, Pyxis recommends a 0.1% or
0.3% concentration calibration standard. The calibration solution could be the sample itself (ClO2 in the
tank), after verified for concentration through titration method or by using a Pyxis SP-910
–
ClO2 HIGH
RANGE DIRECT reading method.
4.1
Calibration and Diagnosis with uPyxis Mobile App
Connect and power the ST-601 probe using the Pyxis Bluetooth adapter (P/N: MA-WB) as shown in the
following connection diagram. The power should be sourced from a 24 VDC power terminal of a
controller. If sufficient controller power is not available, please purchase a PowerPACK Series Auxiliary
Box from Pyxis Lab as an alternative to the MA-WB Bluetooth adapter. PowerPACK will provide ample
power supply, sensor output signal passthrough and Bluetooth access to the ST-601 sensor.