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pHionics STs ORP (Redox) Transmitter

Manufacturer:
The STs ORP (redox) provides ORP (redox) and temperature outputs with a 2-wire, 4-20 mA transmitter in a single, compact device.
Part Number: STS2100S-025
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$1,985.00 ex GST
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Delivery date: 2-3 weeks

All STs Series base prices include a 25 ft cable. 

Product Description

The STs Series ORP (redox) provides ORP (redox) and temperature outputs with a 2-wire, 4-20 mA transmitter in a single, compact device.  The electrode has:

  • double junction
  • platinum band
  • EpGlass body
  • 3-year average electrode life

The electrode is easily replaceable without any special tools.

Exposed surfaces are made of Delrin and 316 Stainless Steel, both of which have excellent chemical resistance.  The cable is polyurethane with Kevlar reinforcement, shielded, water-blocking to provide many years of service.

All parts, including the cable, are easily replaceable.

In addition, input/output isolation and differential amplification virtually eliminate background noise. From environmental datalogging to industrial process control, the STs Series ORP (redox) excels in accurate long-term water quality measurement.


Features and Benefits

Noise Reduction

From crystal-clear streams only touched by radio frequencies to wastewater treatment plants surrounded by heavy machinery, background noise and interference is everywhere.  Our signal conditioning removes background (common-mode) noise from the measurement to ensure high accuracy.  The signal is also sent through a preamplifier to strengthen it before traveling through a twisted-pair, shielded cable that protects the amplified 4-20 mA signal until it reaches the datalogger or controller.

Ease-Of-Use

Typical 2-wire transmitters are relatively easy to set up but improper wiring can result in damage to the transmitter or expensive controller.  The STs Series prevents damage with a reversible input protection so the two wires per parameter can be switched without performance issues.  Additionally, all parts, cable included, are quick and easy to replace without any special tools.  This cuts down on maintenance time and costs, especially in circumstances where cable damage otherwise requires complete replacement of traditional sensors and transmitters.

Isolation

Isolation removes ground loop interference to save troubleshooting time and money by preventing damage to connected electronics in the case of power surges up to 600V.  This allows the STs Series to be used in process control applications without worrying about different grounding potentials of the solution or mounting surface.  It has the added benefit of protecting connected devices and people if exposed to large amounts of current caused by damaged machinery or improper wiring.

Low Power Usage

Sensors and transmitters made by other competitors commonly use more current than the 4-20 mA signal to power their devices, ranging from 3-15 mA additional.  pHionics only ever uses the amount of current required for the signal, allowing STs Series devices to function between 60% to 375% longer on the same battery.  The STs Series also only requires 8 VDC and has a three second turn-on time, further reducing power usage.


2-wire, 4-20 mA ORP (redox) Sensor/Transmitter

Output 4-20 mA
ORP (redox) Range

-1000 to 0 mV

-1000 to +1000 mV

-500 to +500 mV

0 to +1000 mV

Electrode Type Platinum, double-junction,
Automatic Temperature Compensation None
Isolation 600 VDC
Power Supply Voltage 8-40 VDC
Loop Impedance (Max)

200 Ohms at 12 VDC

800 Ohms at 24 VDC

1600 Ohms at 40 VDC

Response time 95% < 20 seconds
Pressure Range 0-100 psi
Wetted Materials 316 SS, Delrin, Viton, glass
Length 13.5 in (34.3 cm)
Width 0.750 in (1.9 cm) maximum
Weight (No cable) 0.50 lbs (0.227 kg)
Linearity ± 4 mV
Accuracy ± 4 mV
Sensitivity ± 1 mV
Stability ± 2 mV
Repeatability ± 10 mV

 

2-wire, 4-20 mA Temperature Sensor/Transmitter

Output 4-20 mA
Temperature Range 0-50°C
Power Supply Voltage 7-40 VDC
Loop Impedance (Max)

200 Ohms at 12 VDC

800 Ohms at 24 VDC

1600 Ohms at 40 VDC

Isolation 600 VDC

 

Cable

Cable Material Polyurethane
Type 4 conductor, Kevlar reinforced, water blocked, shielded, twisted-pair wiring
Maximum Distance 3 miles
Replaceable? Yes

STs Series Initial Setup


pHionics STs Series Setup with HOBO RX3000


STs Series Electrode Replacement


STs Series Cable Replacement

STs Series ORP (redox) FAQ

Answers to common questions regarding STs Series Conductivity care, features, and recommendations

What is the proper way to store an ORP electrode?

ORP (redox) electrodes must be stored in solution to avoid drying out.  We recommend storage in 3.0M potassium chloride (KCl) for maximum lifespan.  Do not store in deionized water or any solution of similar low ionic content as this will significantly reduce electrode life.

How often should the STs Series ORP (redox) be calibrated and/or cleaned?

The frequency of calibration must be determined empirically as rate of drift and debris accumulation differs for each application. Calculating the offset during calibration provides information on whether the electrode is still viable.  See our article on Proper Sensor Calibration for assistance in the process.  Check out our ORP Electrode Care Guide for cleaning and troubleshooting procedures.

How long does the electrode last?

ORP (redox) electrodes last an average of three years.  Electrode life varies significantly based on the qualities of the solution being measured (pH, flow rate, ion concentration etc.) and can range from 6 months to 5 years.

 

Do you provide a warranty?

Yes, our products come with a 2-year warranty, excluding the electrode. These products are designed to last far longer if properly cared for and we will do what we can to help if any problems occur in or out of warranty.  Please don’t hesitate to reach out!

Read our full warranty here.

How can the STs Series be installed/mounted?

The STs Series can be mounted in-line using the optional 1.0″ NTP PVDF DIN Connector, immersed with compression fitting in a 3/4″ pipe, or freely suspended by the Kevlar™ cable.  

How long are STs Series devices expected to last?

While the electrode will require replacement every three years on average, the housing, seals, and cables are intended to last 10-20 years with proper care. To increase longevity of the seals, the Viton O-rings should be relubricated with a silicon grease during each disassembly, or at least inspected for any debris or damage.  The harshness of the solution (high/low pH, extreme salinity, high pressure, etc.) also affects longevity, which is why we offer the option of 316 Stainless-steel or titanium for the metal housing and PVDF (standard) or Delrin for the plastic.  All parts are replaceable to save money and limit waste in the event that any piece gets damaged.

 

What type of electrode is provided?

We provide a combination electrode with silver/silver chloride reference wire that has Teflon double junctions.  It is replaceable instead of refillable to reduce maintenance time. 

What spare parts are recommended?

For critical measurements, a duplicate STs Series combined sensor/transmitter is always recommended so a replacement for every part is always available.  A duplicate simplifies troubleshooting by having a functional STs Series on-hand to compare results.  It also allows for swapping of devices during calibration and cleaning so the measurement or process is not significantly disrupted.  At a minimum, a spare electrode is recommended in the event of damage–or the need for eventual replacement.  This is especially important when waiting for a replacement to be shipped could be detrimental to your application.

Is the output automatically temperature-compensated (ATC)?

No, ORP (redox) is a general reading that varies with temperature drastically depending on the chemical properties of the solution being measured.  Standardization to a given temperature is not useful for a majority of applications.

All STs Series base prices include a 25 ft cable. 

Product Description

The STs Series ORP (redox) provides ORP (redox) and temperature outputs with a 2-wire, 4-20 mA transmitter in a single, compact device.  The electrode has:

  • double junction
  • platinum band
  • EpGlass body
  • 3-year average electrode life

The electrode is easily replaceable without any special tools.

Exposed surfaces are made of Delrin and 316 Stainless Steel, both of which have excellent chemical resistance.  The cable is polyurethane with Kevlar reinforcement, shielded, water-blocking to provide many years of service.

All parts, including the cable, are easily replaceable.

In addition, input/output isolation and differential amplification virtually eliminate background noise. From environmental datalogging to industrial process control, the STs Series ORP (redox) excels in accurate long-term water quality measurement.


Features and Benefits

Noise Reduction

From crystal-clear streams only touched by radio frequencies to wastewater treatment plants surrounded by heavy machinery, background noise and interference is everywhere.  Our signal conditioning removes background (common-mode) noise from the measurement to ensure high accuracy.  The signal is also sent through a preamplifier to strengthen it before traveling through a twisted-pair, shielded cable that protects the amplified 4-20 mA signal until it reaches the datalogger or controller.

Ease-Of-Use

Typical 2-wire transmitters are relatively easy to set up but improper wiring can result in damage to the transmitter or expensive controller.  The STs Series prevents damage with a reversible input protection so the two wires per parameter can be switched without performance issues.  Additionally, all parts, cable included, are quick and easy to replace without any special tools.  This cuts down on maintenance time and costs, especially in circumstances where cable damage otherwise requires complete replacement of traditional sensors and transmitters.

Isolation

Isolation removes ground loop interference to save troubleshooting time and money by preventing damage to connected electronics in the case of power surges up to 600V.  This allows the STs Series to be used in process control applications without worrying about different grounding potentials of the solution or mounting surface.  It has the added benefit of protecting connected devices and people if exposed to large amounts of current caused by damaged machinery or improper wiring.

Low Power Usage

Sensors and transmitters made by other competitors commonly use more current than the 4-20 mA signal to power their devices, ranging from 3-15 mA additional.  pHionics only ever uses the amount of current required for the signal, allowing STs Series devices to function between 60% to 375% longer on the same battery.  The STs Series also only requires 8 VDC and has a three second turn-on time, further reducing power usage.


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