Hydro Instruments 210 Series User manual

Series 210
Amperometric Residual Chlorine Analyzer
Instruction Manual
RAH-210 Rev. 5/12/2021
The information contained in this manual was current at the time of printing. The most current
versions of all Hydro Instruments manuals can be found on our website: www.hydroinstruments.com
1

Hydro Instruments
Series 210 Amperometric Residual Chlorine Analyzer
Table of Contents
I. Functions and Capabilities .....................................................................3
1. Basic Concept Description
2. Galvanic Cell Theory
3. Chlorine Chemistry
4. Measurement Chemistry
5. Basic Specifi cations
II. System Component Description .............................................................6
1. Measurement Cell
2. Temperature Probe
3. Optional Reagent Chemical Feed System
4. Optional pH Sensor
III. Installation ................................................................................................7
1. Sample Water Connection and Control
2. Sample Water Disposal Considerations
3. Sample Point Selection
IV. Setup, Reagents and Conditioning the Analyzer ................................10
1. Reagent Chemical Setup and Requirements
2. Conditioning the Analyzer
V. Calibration and Programming ...............................................................12
1. Modes of the RAH-210 Residual Analyzer
2. Switching Between Modes
3. Operating the Keypad
VI. Explanation of Operation Mode Screens .............................................14
VII. Explanation of Confi guration Mode Screens ......................................16
VIII. Explanation of PID Control Mode Screens ..........................................23
IX. Maintenance & Cleaning ........................................................................25
1. Inlet Filter Screen and Weir
2. Flushing Measurement Cell
3. Reagent Valve (Star Wheel)
4. Cell Assembly
5. Motor Striker Assembly
6. Thermistor
7. pH Probe
X. Troubleshooting .....................................................................................28
XI. Optional Data Logger .............................................................................32
Figures:
1. Hypochlorous Acid Dissociation Curves ..........................................................5
2. Measurement Cell Flow Diagram ....................................................................6
3. Sample Water Piping Diagram ........................................................................8
4. Sample Point Connection Diagram .................................................................9
5. Sample Point Selection Diagram .....................................................................9
6. Operation Menu Flow Chart ..........................................................................13
7. Confi guration Menus from Password 250 .....................................................15
8. PID Control Confi guration Menus from Password 220 ..................................21
9. pH Calibration Menu Flow Chart ...................................................................22
10. RAH-210 Circuit Boards ................................................................................41
11. Monitor Internal Wiring and Connections ......................................................42
Drawings:
Residual Chlorine Analyzer Measurement Cell ........................................34-40
2

I. FUNCTIONS AND CAPABILITIES
1. Basic Concept Description: The Series 210 Residual Analyzer uses a Galvanic measurement
cell consisting of a Cathode and a Copper Anode with the sample water as the electrolyte. This
measurement method is referred to as Amperometric and has been in use for over 50 years.
As described below, the measurement cell can be used to measure the concentration of Free
Chlorine, Total Chlorine, Chlorine Dioxide and other oxidants. Certain chemical species produce
an electrical current in the cell that is proportional to their concentration in the sample water. This
electrical current is read and manipulated by the Series 210 monitor circuit board. The system
employs a motor to continuously clean the measurement cell by the abrasive action of Tefl on balls.
Sample water continuously fl ows through the measurement cell at a controlled rate. A Temperature
sensor is employed to compensate for signal fl uctuations caused by Temperature changes. The
pH of the sample water is either manually entered for pH compensation in the software or else a pH
buff er feed system is used to control the pH in the sample water. If Total Chlorine, Chlorine Dioxide,
or some other oxidants are being measured, then another chemical will be continuously injected into
the sample water prior to its entering the measurement cell.
This analyzer is also equipped with a complete PID Control program, which can be enabled or disabled
as desired. The program accepts a proportional (fl ow) analog 4-20 mA input and uses the residual
value produced by the analyzer. This control program can be enabled as proportional (fl ow pacing),
set-point (residual) or PID (compound loop) control.
2. Galvanic Cell Theory: Pure water has a relatively low conductivity. However, the presence of ionizing
species increases the conductivity. If two electrodes are immersed in a solution containing chemical
species (ions) capable of being reduced (gaining electrons) then this species can move toward
the cathode where it can accept electrons from the cathode. To balance this fl ow of electrons
(current), an oxidation reaction (where an oxidizable species loses electrons at the same rate) must
simultaneously occur at the anode surface.
As the reactions occur at the surface of each electrode, the local concentration of the reducible/
oxidizable species drops, thus creating local concentration gradients. As a result of the
concentration gradients, the process of diff usion moves more of these species toward the
electrodes. The rate at which diff usion moves these species to the electrode surfaces is referred to
as the rate of arrival.
The electrical current produced in the cell is proportional to the rate of arrival of the reducible/oxidizable
species at the electrodes. As the concentration of these species increases, so does the rate of
arrival. Also, as the temperature increases, the rate of arrival increases for a given concentration.
After some temperature compensation, the current is therefore an indication of species concentration.
The current is read by electrically connecting the cathode and anode.
3. Chlorine Chemistry: When Chlorine dissolves in water it forms Hypochlorous Acid according to the
following reactions:
Chlorine Gas: Cl2
Cl
2 + H2O ↔ HOCl + HCl
Sodium Hypochlorite: NaOCl
NaOCl + H2O ↔ HOCl + Na+ + OH–
Calcium Hypochlorite: Ca(OCl)2
Ca(OCl)2 + 2H2O ↔ 2HOCl + Ca++ + 2OH–
3

Hypochlorous Acid is a weak acid that partially dissociates into a Hydrogen Ion and a Hypochlorite
Ion as follows:
HOCl ↔ H+ + OCl–
The degree of dissociation depends on the pH and the Temperature. Regardless of Temperature,
below a pH of 5 the dissociation of HOCl remains virtually zero and above a pH of 10 the dissociation
of HOCl is virtually 100%. Figure 1 shows this dissociation curve at several Temperatures. The sum
of Hypochlorous Acid and Hypochlorite Ion is referred to as Free Available Chlorine.
When Ammonia Nitrogen is present in the water, some or all of the Free Available Chlorine will be
converted into Chloramine compounds according to the following reactions:
NH
3 + HOCl → H2O + NH2Cl (Monochloramine)
NH
3 + 2HOCl → 2H2O + NHCl2 (Dichloramine)
NH
3 + 3HOCl → 3H2O + NCl3 (Nitrogen Trichloride)
The sum of the Chloramine compounds is referred to as “Combined Available Chlorine”. Also, the
sum of Free Available and Combined Available Chlorine is referred to as “Total Available Chlorine”.
4. Measurement Chemistry:
Free Chlorine Measurements: As discussed above, Free Chlorine is the sum of Hypochlorous
Acid and Hypochlorite Ion concentrations. Hypochlorous Acid is a reducible species in the Series
210 Residual Chlorine Analyzer. Therefore the measurement cell can be used to measure the
concentration of Hypochlorous Acid.
This measurement can be used to determine the concentration of Free Chlorine by one of two
methods. Consider Figure 1 in the discussion of both methods.
First, an acidic buff er solution can be injected into the water sample stream to reduce the pH below 5,
so that all of the Free Chlorine is in the form of Hypochlorous Acid.
Second, pH and Temperature measurements can be used to continuously determine the degree of
Hypochlorous Acid dissociation through software. The instantaneous degree of dissociation value
can then be used in conjunction with the Hypochlorous Acid concentration measurement to determine
the Free Chlorine concentration. This method will be referred to as “pH Compensation”.
The reaction at the cathode surface in this measurement is as follows:
HOCl + 2e– → Cl– + OH–
Total Chlorine Measurements: As discussed above, Total Chlorine is defi ned as the sum of Free
Available Chlorine and Combined Available Chlorine. Combined Available Chlorine species are not
reducible in the Series 210 measurement cell. Therefore, the following technique must be employed
to obtain a measurement.
First, Potassium Iodide (KI) is injected into the sample water so that all species comprising Total
Chlorine react to form Potassium Chloride (KCl). The measurement cell then measures KCl
concentration in the same fashion that it can measure HOCl concentration. Since KCl concentration
is proportional to Total Chlorine concentration, the measurement of KCl is also a measurement of
Total Chlorine concentration. The relevant reactions are as follows.
Free Chlorine Residual:
2H + 2HOCl + 2KI ↔ I2 + 2KCl + 2H2O
4

Combined Chlorine Residual:
3H
2O + 2NH2Cl + 2KI ↔ 2KCl + I2 + 2NH4OH + ½O2
2H
2O + NHCl2 + 2KI ↔ 2KCl + I2 + NH4OH + ½O2
5H
2O + 2NCl3 + 6KI ↔ 6KCl + 3I2 + 2NH4OH + 1.5O2
Second, the pH must be reduced to the range of 4.0 to 4.5 in order to prevent any dissociation of the
Hypochlorous Acid or the Potassium Chloride (KCl).
5. Basic Specifi cations
Temperature Range: 0º to 50º C (32º to 122º F).
Sample Water Flow Rate: 500 ml/min (8 gal/hr) ideal
150 ml/min (2.4 gal/hr) minimum
Sample Pressure: 5 psig (0.3 bar) maximum at inlet point.
Sample Supply: Continuous. Electrodes must be kept wet with fresh water.
Speed of Response: 4 seconds from sample entry to display indication.
T
90: Approx. 90 to 120 seconds
T
100: Approx. 10 minutes.
Sample Water: Metal ions or certain corrosion inhibitors may eff ect analyzer operation.
Range: 0 to 0.1 to 0 to 20 mg/l (PPM). Field adjustable.
Power Consumption: 10 W max.
Power Requirements: 120VAC, 50/60 Hz or 240VAC, 50/60 Hz, single phase.
Accuracy: 0.003 mg/l or +/-1% of range, whichever is larger.
Sensitivity: 0.001 mg/l (1 ppb)
Input Signals: (5) Analog 4-20 mA.
Output Signals: (4) Isolated 4-20 mA Analog (Res, pH, Temp, Turbidity, or Control).
Digital Communication: Modbus RS-485 Two-Way
pH Sensor Input: Included.
Temperature Sensor Input: Included (for 10K Ohm thermistor).
Relay Contacts (4): 10 Amps @ 120 VAC or 24 VDC, resistive load, 5 Amps @ 240 VAC, resistive
load.
Reagent Requirements
Free Chlorine (pH Compensated): None.
Free Chlorine (not pH Compensated):
pH Buff er or CO2 gas.
Total Chlorine: pH Buff er or CO2 gas
and Potassium Iodide.
Chlorine Dioxide: pH Buff er and Glycine.
Bromine Chloride: pH Buff er or CO2
gas and Potassium Iodide.
Iodine: pH Buff er or CO2 gas.
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5

II. SYSTEM COMPONENT DESCRIPTION
Refer to Figure 2 for this section.
1. Measurement Cell: The measurement electrodes consist of a cathode and a Copper anode. The
measurement electrodes are mounted in a PVC housing assembly. The electrodes are in the shape
of concentric cylinders. The cathode is the inner smaller cylinder and the anode is the outer larger
cylinder. The sample water fi lls the gap in between the electrodes and continually fl ows in the upward
direction. The detailed description of the electro-chemical process can be found in section I.
The Series 210 Residual Chlorine Analyzer also employs a continuous electrode cleaning method.
The purpose of this method is to keep the electrode surfaces clean and free of chemical desposits
to ensure consistent measurement readings. The cleaning is accomplished by fi lling the space
between the electrodes with roughly 130 7⁄32" diameter PTFE cleaning balls and continuously driving
them around the annular gap with a rotary motor. These balls and the electrodes require periodic
maintenance and replacement as described in Section VI.
2. Temperature Probe: A Thermistor is used to continuously measure the sample water Temperature.
The Temperature can be displayed and retransmitted by the Series 210 Residual Chlorine Analyzer.
It is also used in software for signal manipulation for the two following reasons:
Temperature compensation for the effects of Thermal Diffusion: As described in Section I, the rate of
arrival at the electrode surfaces is dependent on the Temperature of the sample water. If the device
is being used at a location with constant water Temperature, then this compensation is not necessary.
However, if the sample water Temperature experiences signifi cant fl uctuations, then the raw signal
will be aff ected and software Temperature compensation is necessary for accurate readings.
For use in pH compensation: As described in Section I, if the pH buff er is not being used to lower the
sample water pH, then pH compensation is necessary to achieve accurate measurements.
3. Optional Reagent Chemical Feed System: The Series 210 Residual Chlorine Analyzer can be
fi tted with a mechanically driven reagent feed system. The chemical reagent solution is continuously
injected at a controlled rate by a mechanical system driven by the motor that is used to drive the
cleaning balls in the measurement cell. Section I.5 outlines the various reagent solutions that may be
needed depending on the target measurement species and the measurement method. If operating
properly, the reagent feed system should feed the solution at a rate of 3⁄4" to 11⁄8" (20 to 30 mm)
level change in 24 hours.
4. Optional pH Probe: If the unit is not fi tted with the reagent feed system then it is recommend that
the unit be equipped with an external pH probe. This probe is mounted in its own acrylic chamber
located to the right of the measurement cell and used used to compensate for the eff ects of pH
as described in section I. It is not recommended that this compensation method be used where
the sample water being measured is consistently above pH 8.5. Should this be the case Hydro
Instruments recommends utilizing the reagent feed system.
FIGURE 2
Motor
Water
Sample
Inlet
Cleaning
Balls
Rotating
Striker
Cylindrical
Copper
Electrode
Probe
Screen
Drain
Electrical
Signal
Overflow
to Drain
Rotary Valve
Buffer Chemical Feed
6

III. INSTALLATION
Refer to Figure 3 for this section.
1. Sample Water Connection and Control: The following are some considerations relating to the
sample water supply. The Series 210 Residual Chlorine Analyzer requires a constant supply of sample
water at a controlled rate and pressure. Precautions should also be taken to ensure that the sample
water reaching the measurement cell is not altered as it passes through the sample water piping. Also,
the connection to the sample point should be made in such a way to avoid receiving air or sediment
from the pipe. Consider fi gure 4 when creating your sample water line
Flow: As mentioned in the specifi cations in Section I, the sample water fl ow rate should be
controlled at 500 ml/minute (8 GPH). A fl ow meter and rate control valve may be necessary to
achieve and maintain this fl ow rate. This can be installed upstream from the measurement cell.
Pressure: Where the sample point has a water pressure higher than 5 psig, a pressure-reducing
valve must be employed to deliver the sample water to the measurement cell. The sample water
entering the measurement cell should be at a pressure below 5 psig. If the sample point pressure
is too low, then it may be necessary to use a sample pump to deliver the sample water to the
measurement cell.
Other Considerations: It should be considered, that any biological growth inside the sample
piping system will have some chemical demand. This can cause the sample water reaching the
measurement cell to not be an accurate sample. For example, the chlorine residual could fall as the
sample water passes through the sample water piping system. For this reason, it may be necessary
to periodically disinfect the sample water piping system to prevent any biological growth. Also, it is
generally not recommended to use a fi lter in this piping system because as the fi lter collects particles it
will develop a chlorine demand and therefore, the chlorine residual in the sample water will be reduced
by the fi lter, leading to inaccurate readings. However, in certain installations with signifi cant amounts
of solids in the sample water (particularly iron and manganese) the use of sample water fi lters may be
necessary.
2. Sample Water Disposal Considerations: If no reagent chemical is being injected, then the disposal
of the water departing the measurement cell is usually not a signifi cant concern. However, if some
reagent chemicals are being injected, then all applicable regulations should be considered before
making the decision of how and where to dispose of the wastewater exiting the measurement cell.
Refer to the MSDS of the chemical in question for instructions on proper disposal.
3. Sample Point Selection: Consider Figure 5 for this section.
There are at least two general concepts to consider when selecting the sample point location. First, is
to select a point that allows reliable determination of the chemical residual concentration at the most
critical point for the particular installation. Second, is to take into consideration the chemical injection
control timing. A balance between these considerations must be reached.
Each system is unique, however in general the goal of the chemical injection is to achieve some result
by maintaining a certain chemical residual concentration at a particular point in the system. For
example, to maintain a specifi c chlorine residual at the exit of the drinking water facility. The location
should be selected so that the injected chemical is already fully mixed so that an accurate sample can
be sent to the measurement cell.
WARNING! Do not run analyzer without sample water running through! Lack of,
or interruption of water fl ow to analyzer cell can overheat the motor and cause
premature failure.
7

FIGURE 3 (Sampling Examples)
Sample
Pump
Low Pressure
Sample Water
Source
Flush Valve
to Drain
Pressure entering
RAH-210 must be
reduced to 5 psig
(0.3 bar) or less
Sample Water
Flow Meter
Y-Strainer Pressure Reducing
Valve Assembly
Pressure Reducing
Valve Assembly
Grab
Sample
Valve
To Drain
Pressurized
Sample Water
Source
It should also be considered that the sample point should be located such that the residual
reading can be used as a control signal for the chemical injection. Especially, it should be
considered that if there is a long time delay between chemical injection changes and the
change being detected by the measurement cell, then chemical injection control is adversely
aff ected. The delay time should be kept as short as possible. We recommend that the time
be less than 5 minutes.
8

!IR
3EDIMENT
!IR
3EDIMENT
!IR
3EDIMENT
!IR
3EDIMENT
0//2 0//2
'//$ "%34
FIGURE 4 (Sample Sources)
FIGURE 5 (Installation Example)
TRUE
BLUE
TRUE
BLUE
TRUE
BLUE
40
80
100
140
180
200
40
80
100
140
180
200
40
80
100
140
180
200
40
80
100
140
180
200
Min. = 10 x Dia.pipe
Ideal = 20 x Dia.pipe
Residual Signal (4-20mA)Water Flow Signal (4-20mA)
NET #1 = 1234
NET #2 = 5678
Residual Chlorine Analyzer
RAH-210
Wall Panel Omni-Valve
Vacuum Regulator
Ejector
Sample Water PRV
RAH-PRV
Corporation Stop
Vent
9

IV. SETUP, REAGENTS, & CONDITIONING THE ANALYZER
IMPORTANT NOTE: Prior to starting the analyzer, turn the striker with your thumb (from left to right) to
be sure the motor turns freely. If the motor becomes stuck or is diffi cult to turn by hand, the problem
must be identifi ed and corrected prior to starting the analyzer. See Section X (Troubleshooting).
1. Reagent Chemical Setup and Requirements: This section pertains to systems using the reagent
feed system. The following explains what reagents are to be used depending on the measurement
method.
a. Free Chlorine with pH compensation in software – No reagents required.
b. Free Chlorine without pH compensation – Requires pH buff er solution.
c. Total Chlorine – Requires pH buff er and potassium iodide.
d. Chlorine Dioxide – Requires pH buff er and glycine.
e. Bromine Chloride – Requires pH buff er and potassium iodide.
f. Iodine – Requires pH buff er.
NOTE: The 2 liter reagent bottle will last for approximately one week of continuous use.
Use of pH buffer: It should be noted that the pH buff er feed system is designed to reduce pH in the
sample cell in order to minimize or eliminate the eff ects of dissociation.
The following pH buff er is recommended:
Sodium acetate trihydrate and glacial acetic acid can be mixed with distilled deionized water as
follows:
a. Add 850 mL of distilled deionized water to a 1⁄2 gallon (2L) bottle.
b. Add 486 grams sodium acetate trihydrate crystals and mix until all the crystals are dissolved.
c. Add 952 grams or 907 mL of glacial acetic acid to the bottle.
d. Fill the bottle to the top with distilled deionized water. Mix thoroughly.
e. If necessary check the pH of the solution (pH = 4). If not, add more acetic acid to lower the pH.
f. To conserve buff er you may also dilute 50:50 with distilled deionized water in a separate 1⁄2 gal (2 L)
container and store the remaining solution for later use. However, please be aware that doing this
will lower the buff ering capacity of the solution.
Use of Potassium Iodide reagent: This reagent is always used together with the above mentioned
pH buff ers. To prepare the combined reagent solution, follow this procedure:
a. Fill a 1⁄2 gallon (2 L) bottle half way with distilled deionized water.
b. Add potassium iodide crystals as follows to the 1⁄2 gallon bottle.
c. Shake the bottle until the crystals are all dissolved completely.
d. Fill the 1⁄2 gallon bottle to the top with the pH buff er solution.
TABLE 1
Potassium Iodide (KI) (grams) Analyzer Range (ppm) (mg/l)
2.65 0 to 0.2
5.3 0 to 0.5
21 0 to 2.0
32 0 to 3.0
53 0 to 5.0
105 10 or 20
10

NOTE: Due to the nature of the potassium iodide (KI), the above solution will have a shelf life
of approximately 15 days. This is because of the oxidation of the KI in solution. As this occurs,
the solution will turn a golden color. Adding a drop of a reducing agent such as 0.02N sodium
thiosulfate or 0.00564N phenylarsine oxide to the reagent can reverse the oxidation process.
After the reducing agent has been added, the solution should turn clear again. If the solution
turns dark brown or black color, then the KI has oxidized and a new reagent solution must be
prepared. It is suggested that this reducing agent be added once every 14 days or as needed to
preserve the solution.
Use of Glycine reagent: This reagent is always used together with the above mentioned pH buff ers.
To prepare the combined reagent solution, follow this procedure:
a. Fill a 1⁄2 gallon (2 L) bottle with 500 mL of distilled deionized water.
b. Add 190 to 210 grams of glycine crystals as follows to the 1⁄2 gallon bottle.
c. Fill the 1⁄2 gallon bottle to the top with the pH buff er solution and shake to mix thoroughly.
Ensure that the glycine crystals are dissolved completely.
2. Conditioning the Analyzer: Before calibration is carried out, the analyzer must be operated for at
least 24 hours to allow the readings to stabilize. If the reagent feed system is being used, then the
following procedure must be followed also.
a. Holding the full reagent bottle upright, pull the tapered plug upward until the hole in the cap is
plugged. Turn the bottle upside down and install in the reagent feeder body. The bottle will seal
against the o-ring and the tapered plug will open due to gravity.
b. Start the sample water fl ow to the measurement cell. Water must be fl owing over the weir in the
sample fi lter chamber to the drain.
c. A fl ow rate of 500 ml/minute (8 GPH) should be provided. When set properly, the sample
water level in the inlet weir should be close to or slightly overfl owing the inner drain lip. Under
all circumstances, the electrodes must be kept wet, even if the sample water fl ow must stop
periodically. Maximum sample water pressure is 5 psig. See Figure 3.
d. Turn on the power to the analyzer.
e. Check for air bubbles in the sample line and reagent line. Remove any air bubbles.
f. Allow the analyzer to operate with the reagent feeding and the sample water fl owing for at least
24 hours. After this, the analyzer can be calibrated.
11

V. CALIBRATION AND PROGRAMMING
1. Modes of the RAH-210 Residual Analyzer
a. Operation Mode (See Section VII): This is the mode used during normal operation of the RAH
210 Analyzer. It provides a display of the current residual reading, water temperature reading,
pH and any alarm conditions that may exist.
b. Configuration and Calibration Mode (Programming) (See Section VIII): This mode is used to
set up the display options, operational parameters and other features.
c. PID Control Mode (See Section IX): This mode enables and confi gures the PID Control
program in the software. The program can perform proportional, set-point (residual) or compound
loop control. One or more of the analog outputs (AO1 to AO4) can be programmed to transmit a
4-20 mA control signal.
2. Switching Between Modes
a. Operation Mode: This is the standard mode, which appears during initial powering of the device.
To return to this mode from any other screen simply press the button repeatedly.
b. Configuration and Calibration Mode: This mode is accessed from the Operation Mode by
pressing the button until the password screen is reached. Then enter the password “210” and
then press the button.
c. PID Control Mode: When enabled, this program will display several general status and control
screens in the Operation Mode. To access the screens, which allow this program to be set-up,
press the button (in the Operation Mode) until the password screen is reached. Then enter the
password “220” and press the button.
3. Operating the keypad
1. Navigation: To move from one screen to another, simply press the and buttons to reach
the desired screen. Navigation between screens is possible in either direction.
2. Adjustment of Displayed Parameters: To adjust a displayed parameter in the Confi guration
Mode, simply use the and buttons to increase or decrease. Once a parameter has been
set to the desired position, pressing either or button to leave the screen will cause the new
parameter to be stored. To select a blinking option (such as “Temperature Cal – Yes/No”), use the
arrow buttons as needed to make the desired selection blink then press the button.
12

FIGURE 6 (Operation Menu Flow Chart)
FIGURE 6.1 (Operation Menu Flow Chart) FIGURE 6.2 (Control Type Dependent Operation Screens)
Residual= 1.20PPM
Temp= 72F pH= 7.00
Alarm Status
Normal
Skip to RES Span Cal
No Yes
Skip to RES Span Cal
No Yes
Enter Password
210
Range= 50mV T=72F
pH=7.00 MF=1.00
Input/Output HOLD
Time= 10 min HOLD=Off
Input/Output HOLD
Time=10min HOLD= Off
Resl Filter= 30 secs
pH Filter= 60 secs
Flow Stop = 00 %
Com Errors = 0
pH 7.00 4.00 10.00
mV 0 177 -177
pH TC=291.6 S=-59.0
Offset 7pH=0mV
Cell mV = 23
ReslAdc = 1883
HOLD
Turb1 = 0.74 NTU
Turb2 = 46 NTU
This screen is only present
if Turb1 and/or Turb2 are
enabled.
AUTO FLO 24.9 %
¹¹¹¹ PO1 0.0KG/H
Set Dosage
1.00
Alarm Status
None
Enter Password
220
AUTO > MANL >
increments of 1
0.01 increments
MANL FLO 24.9 %
¹¹¹¹ PO1 0.0KG/H
Set PO1(Valve)
¹¹¹¹ 0.0KG/H
Alarm Status
None
Enter Password
220
MANL > AUTO >
increments of 1
0.1 increments
Set Dosage
1.00 0.01 increments
“Flow Pacing” AUTO “Flow Pacing” MANL
AUTO RES 1.24 PPM
¹¹¹¹ PO1 0.0KG/H
Set Point Res/ORP
2.00 PPM
Alarm Status
None
Enter Password
220
AUTO > MANL >
increments of 1
0.01 increments
MANL RES 1.24 PPM
¹¹¹¹ PO1 0.0KG/H
Set PO1(Valve)
¹¹¹¹ 0.0KG/H
Alarm Status
None
Enter Password
220
MANL > AUTO >
increments of 1
0.1 increments
Set Point Res/ORP
2.00 PPM 0.01 increments
“Residual/ORP” AUTO “Residual/ORP” MANL
Enter Password
220
AUTO RES 1.24 PPM
¹¹¹¹ PO1 0.0KG/H
AUTO FLO 24.9 %
¹¹¹¹ PO1 0.0KG/H
Set Point Res/ORP
2.00 PPM
Set Dosage
1.00
Alarm Status
None
AUTO > MANL >
AUTO > MANL >
0.01 increments
increments of 1
0.01 increments
MANL RES 1.24 PPM
¹¹¹¹ PO1 0.0KG/H
MANL FLO 24.9 %
¹¹¹¹ PO1 0.0KG/H
Set Point Res/ORP
2.00 PPM
Set PO1(Valve)
¹¹¹¹ 0.0KG/H
Alarm Status
None
Enter Password
220
MANL > AUTO >
MANL > AUTO >
0.01 increments
increments of 1
0.1 increments
Set Dosage
1.00 0.01 increments
“Compound Loop” AUTO “Compound Loop” MANL
Resl Span Cal
8.0PPM ( 796 )
AUTO FLO 24.9 %
¹¹¹¹ PO1 0.0KG/H
This screen is not present
if Control Type
is set to OFF.
Screens shown with grey border
are hidden screens,
accessed by holding -
at the appropriate screen
(typically 2nd to last in the branch)
ReslAdc0 = 0
ReslCal0 = 0
ReslAdc1 = 1543
ReslCal1 = 120
Cal Range=50 mV
C0=0 mV C1=25 mV
Temp = 72F
Therm = 101511 ohms
Modbus Baud= 19200
Node= 1 Data= 8/N/1
25 mV
50 mV
On
Off
13

VI. EXPLANATION OF OPERATION MODE SCREENS
Main: This screen will display the residual value as well as the sample water temperature. If “Manual”,
“Auto” or “Monitor” is selected as the “pH Compensation Mode”, the main screen will also display the
pH value.
Alarm Status: Displays any existing alarm conditions.
Turbidity: This screen is present when one or more of the two Turbidity channels is enabled. It displays
Turbidity reading(s).
Control Operational: This menu appears when the PID Control program is enabled. It displays the PID
Control Status (Manual or Auto), the Process Variable(s) and the Process Output. To change between “Auto”
and “Manual” control status, press the button. When Compound Loop Control is in use, there will be two
Control Operation screens.
Set Dosage: This menu appears when the PID Control program is enabled and the Control Mode is
selected as either Proportional or Compound Loop Control. This is an adjustable factor that is multiplied to
the
incoming fl ow signal.
Set Point RES/ORP: This menu appears when the PID Control program is enabled and the Control Mode
is selected as either Residual or Compound Loop Control. This is an adjustable factor that represents the
desired value for residual (or ORP).
Set PO1: This menu appears when the PID Control program is enabled and the control status is set to
“Manual”. On this screen, the control output can be changed by pressing the and buttons.
Skip to RES Span Cal?: This screen allows a direct jump to the residual span cal screen (bypassing the
password). To pass this screen, press the button twice or press the button when the word “No” is
blinking.
Enter Password: This screen allows access to the confi guration or PID Control menus. Enter the desired
password and then press the button.
14

FIGURE 7 (Configuration Menus from Password 250)
HOLD
HOLD
Setup: Resl Temp pH Turbid Aout Alarm DL
Setup: Resl Temp pH Turbid Aout Alarm DL
Setup: Resl Temp pH Turbid Aout Alarm DL
Residual Units PPM
PPM
MG/L
Resl Decimal Posn 00.00
000.0 00.00 0.000 00000
Residual Full Scale 5.00 PPM Residual Low Alarm
0.00 PPM (0=Off)
Residual High Alarm
5.00 PPM
Sample Flow Stop Alm Off
On
Off
Begin Resl Span Cal? Skip Hold/Begin
Resl Span Cal 5.00PPM (5000 )
Temp Sample Cal 38F
pH Low Alarm
6.00
pH High Alarm 9.00 pH Compensation Mode AUTO
AUTO
MANUAL
MONITOR
NONE
Setup: Resl Temp pH Turbid Aout Alarm DL Turbidity 1 = Off Turbidity 2 = Off Turbidity 1 = Off Turbidity 2 = Off Turb 1 Decimal Posn 00.00
000.0 00.00 0.000 00000
Turb 1 Full Scale 10.0 NTU Turb 1 High Alarm 1.00 NTU Turb 2 Decimal Posn 00.00 Turb 2 Full Scale 10.0 NTU Turb 2 High Alarm 1.00 NTU Turb 1 Span Cal? Skip Hold/Begin Turb 1 Span Cal? Skip Hold/Begin Turb 2 Span Cal? Skip Hold/Begin Turb 2 Span Cal? Skip Hold/Begin
Turb 1 Span Cal 10.00 NTU Turb 2 Span Cal 10.00 NTU
Begin Resl Zero Cal? Skip Hold/Begin
Resl Zero Cal 0.00PPM (0 )
Begin Resl Span Cal? Skip Hold/Begin
Resl Span Cal 0.00PPM (5000 )
Turb 1 Zero Cal? Skip Hold/Begin Turb 1 Span Cal? Skip Hold/Begin
Turb 1 Zero Cal 0.00 NTU Turb 1 Span Cal 50.00 NTU
Turb 2 Zero Cal? Skip Hold/Begin Turb 2 Span Cal? Skip Hold/Begin
Turb 2 Zero Cal 0.00 NTU Turb 2 Span Cal 50.00 NTU
000.0 00.00 0.000 00000
Residual Temperature pH Turbidity
Data Logger = On
Setup: Res1 Temp pH Turbid Aout Alarm DL
Setup: Res1 Temp pH Turbid Aout Alarm DL
Setup: Res1 Temp pH Turbid Aout Alarm DL
Select AO1 Resl
Resl Temp
pH
Turb 1 Turb 2
PO1
Select AO2 Resl Select AO3 Resl Select AO4 Resl
Alarm Mode Non-latching
Non-latching
Latching
Alarm Delay Time 10 secs Select Relay 1 Resl High Alarm
Data Log Frequency 60 secs Set Time and Date? No Yes
On
Off
Set Time and Date? No Yes Change Time and Date Thu Feb 22 ,18 14:43 Time and Date Was Changed!
Resl High Alarm
Resl Low Alarm
Turbid 1 High Alarm Turbid 2 High Alarm
pH High/Low Alarm
Any Alarm
Sample Flow Stop Alm
Select Relay 2 Resl High Alarm Select Relay 3 Resl High Alarm Select Relay 4 Resl High Alarm
Analog Outputs Relays Data Logger
AO1 Cal: 4mA= 795 20mA=3986 AO2 Cal: 4mA= 802 20mA=4005 AO3 Cal: 4mA= 794 20mA=3979 AO4 Cal: 4mA= 798 20mA=3988
HOLD
Begin pH 7.0 Cal? 520mV Skip Begin Begin pH 7.0 Cal? 520mV Skip Begin pH 7.0 Buffer Cal Wait…25 Begin pH 10.0 Cal? 520mV Skip Begin Begin pH 10.0 Cal? 520mV Skip Begin pH 10.0 Buffer Cal Wait…25
pH Calibration Type
7.0 and 10.0
Sample
4.0 and 7.0
4.0 and 10.0 7.0 and 10.0
Temperature Mode AUTO
AUTO MANL
Temperature Units
F
F C
Screens shown with grey border
are hidden screens,
accessed by holding -
at the appropriate screen
(typically 2nd to last in the branch)
Screens shown with grey border
are hidden screens,
accessed by holding -
at the appropriate screen
(typically 2nd to last in the branch)
15

VII. EXPLANATION OF CONFIGURATION MODE SCREENS
Main: The Confi guration Mode is structured as a “tree branch” program. The main screen is the trunk from
which each branch can be accessed (fi gure 7 pg. 15). Seven options appear on this screen, with one option
blinking. To change which option is blinking, press the button. To select the blinking option, press the
button. To access the confi guration mode from the operation mode scroll down and enter “210” as the
password when prompted.
Res: This branch accesses the settings for the residual (as related only to the analyzer). To calibrate the
instrument residual, follow the steps below.
Residual Units: Select PPM or MG/L.
Residual Decimal Position: Select desired decimal place for residual.
Residual Full Scale: Enter desired full scale (range). This setting is what a 20 mA residual output
signal represents. An output of 4mA always represents a residual of zero.
Residual Low Alarm: Enter low residual alarm trip-point (if desired).
Residual High Alarm: Enter high residual alarm trip-point (if desired).
Sample Flow Stop Alarm: Enable (On) or Disable (Off ) the fl ow stop alarm. If the optional sample fl ow
stop switch is installed this option can be enabled. If the optional sample fl ow stop switch is not installed
this option should be disabled. In the event that the analyzers sample water fl ow stops the analyzer will
indicate a “Sample Flow Stop” alarm. An alarm relay can be set to remotely indicate this alarm status.
NOTE: While the “Sample Flow Stop” alarm is active all 4-20mA outputs will be frozen and will only
return to a live reading once the “Flow Stop” alarm is no longer active.
Begin Residual Zero Cal?: The analyzer is shipped with the default zero calibration. A zero calibration
may need to be performed in the fi eld for best accuracy. To access this calibration menu, follow the
steps noted on Figure 7. To pass by this screen, press the button twice or press the button when
the word “Skip” is blinking. To perform a residual zero cal, press the button to make the word “Begin”
blink. Then press the button.
Residual Zero Cal: Enter residual value of “zero” sample water. When the residual value on the screen
matches the known residual of the “zero” sample water, press the button. A confi rmation screen
should appear indicating that the calibration was performed.
NOTE: The residual zero calibration does not necessarily have to be performed with sample water at a
0.00 PPM residual. However, it is advisable to perform zero and span calibrations with two samples of
significantly differing residual values.
Begin Residual Span Cal?: To pass by this screen, press the button twice or press the button
when the word “Skip” is blinking. To perform a residual span cal, press the button to make the word
“Begin” blink. Then press the button.
Residual Span Cal: Enter residual value of “span” sample water. When the residual value on the
screen matches the known residual of the “span” sample water, press the button. A confi rmation
screen should appear indicating that the calibration was performed.
Temp: This branch accesses the settings for the temperature. To calibrate the temperature, follow the steps
below.
Temperature Units: Select “F” (Fahrenheit) or “C” (Celsius).
Temperature Mode: Select “Manual” or “Auto”. Automatic enables the temperature to be automatically
detected via the thermistor.
Manual Temperature: This screen appears when Temperature Mode “Manual” has been selected.
Enter the sample water temperature using the and buttons.
Temp Sample Cal: This screen appears when Temperature Mode “Auto” has been selected. The
temperature displayed represents what the program interprets the current temperature reading to be. If
16

necessary, adjust the displayed temperature using the and buttons.
NOTE: Displaying the temperature on the main operating screen is optional and can be changed by
accessing a hidden menu as detailed in the note on Figure 7.
pH: This branch accesses the pH compensation settings and pH electrode calibration.
pH Compensation Mode: Choose your pH compensation method by pressing the plus key until the
desired pH compensation method is displayed. Your choices of pH compensation are:
1. None: In this mode, the analyzer will assume the pH of the sample water is either stable or has been
buff ered low enough such that dissociation is not a concern. Note that in this mode, the pH value
is not displayed on the main operations mode screen. If this mode is chosen, no pH electrode is
needed.
2. Auto: In this mode, the pH value of the sample water is monitored using a pH electrode (available
through Hydro Instruments) and compensation is performed automatically in the controller’s software.
3. Manual: In this mode, the pH value of the sample water can be entered and will remain fi xed unless
changed. See Figure 9 for explanation of this option.
4. Monitor: In this mode, the sample water pH will be continuously monitored by the pH electrode but it
will have no eff ect on the residual reading.
If Auto or Monitor modes have been chosen; on the following screen you can select your calibration type.
Select the calibration method based on recommendations A-D below.
pH Calibration Type: The residual analyzer allows the user to select from four diff erent calibration
methods including: 4-7 pH calibration, 7-10 pH calibration, 4-10 pH calibration, and the sample pH
calibration. The calibration type to use is completely up to the user. However Hydro Instruments
recommends using the following setting:
A. If pH buff ers are not available, then use the “sample” calibration. This is only a one point calibration
(your sample) and will automatically calculate an ideal calibration slope. This provides reasonable
accuracy if the sample pH is close to seven and pH of the process is relatively stable.
B. If sample pH is less than seven, use the “4-7” calibration.
C. If sample pH is greater than seven, use the “7-10 calibration.
D. If sample stream is subject to wide swings in pH, use the “4-10” calibration.
Quick notes to increase calibration accuracy:
• Before placing the pH electrode into a buff er for calibration, blot the bottom of the probe with a clean
microfi ber cloth.
CAUTION: Take care not to scratch the probe surface as this will damage the probe and aff ect your
readings.
• Allow the pH meter to sit in the buff er solution for a few seconds prior to calibration. The longer it sits
in the buff er solution, the closer it will be to the ideal value. Generally 15-30 seconds for a new probe.
When calibrating the pH electrode the controller software will count down from 25 seconds to ensure
good calibration.
• Keep the pH sensor and buff er solution still when calibrating your instrument. Vigorous movement of
the sensor can disrupt readings and lead to inaccurate calibrations, should the pH electrodes reading
be disrupted during calibration the countdown will reset.
• Select a pH range for calibration that will be similar to your operating conditions. For example, if the
operating range is 7.80 to 8.10 then perform a 7.00 and 10.00 calibration.
• When calibrating your sensor, always use a fresh buff er solution and discard the buff er after use.
17

• Be aware of the temperature of the buff ers being used. Generally buff er manufactures write on their
label at what temperature the pH is its true value (generally 77°F, 25°C). Temperature can infl uence
dissociation and thus if your calibration is done with a buff er not at its prescribed temperature, your
calibration will be inaccurate. It is best to calibrate with buff ers that have an accurate pH close to your
operating conditions.
• Air bubbles and other liquids can form around the outside of the sensor and aff ect the accuracy of the
reading. Be sure to remove any air bubbles upon installation.
4 – 7 pH, 7 – 10 pH & 4 – 10 pH: These are two point calibrations carried out with two known pH buff er
solutions.
1. In the Temperature calibration screen, set the Temperature mode to manual and enter the actual
buff er solution temperature.
NOTE: pH buffer calibrations are somewhat temperature dependent. pH buffers are usually accurate
at 25ºC. Error in pH readings can occur if buffer temperatures are drastically different from their
prescribed temperature (+/- 5ºC). If the temperature difference is greater than this margin, consider
adjusting buffer temperature or performing a sample calibration.
2. Once the calibration method is selected, the fi rst buff er solution required will be displayed on the
screen. Place the pH electrode into the appropriate buff er and select ‘Begin’.
3. The software waits for the reading to stabilize for 25 seconds before accepting or rejecting it as a
valid calibration point. The countdown timer will appear on the screen in real-time. Note: The pH
value will not be displayed.
4. If the calibration point is accepted, an “accepted” screen will appear. Press down to clear the screen
and the next buff er solution required will appear.
5. Place the pH electrode in the appropriate buff er solution and select ‘Begin’.
6. The software will wait for a stable reading over 25 seconds. If the second calibration point is
accepted, an “accepted” screen will appear. Press down to clear and the pH calibration is complete.
7. Place the pH electrode back into the sample solution and change the Temperature back to the original
operating conditions.
Sample Calibration: This calibration is carried out with the pH electrode left installed in its holding cell
with the sample water fl owing through it. However, be sure that the Temperature displayed on your unit
is accurate before calibrating the pH.
1. If this calibration option has been selected, the following screen will require the operator to enter the
pH of the sample water in which the calibration will be done.
2. Use a hand held pH meter to measure the pH of the sample water and then enter the pH of the
sample on the screen.
3. Before proceeding check that no air bubbles have formed on the tip of the pH electrode. Select
‘Begin’; the software will wait for a stable reading over 25 seconds before accepting or rejecting the
calibration point. If the calibration point is accepted, press the down key and the pH calibration is
complete.
NOTE: If at any point your pH calibration is rejected, the entire calibration procedure will need to be
repeated. If the problem persists, see the troubleshooting section below.
AOut: This branch accesses the settings for the four 4-20mA output channels. (AO1, AO2, AO3, AO4)
Select AOX: Each of the four analog output channels can be independently set to represent one of the
following parameters.
18

Residual: When “resl” is selected, the analog output will send a 4-20 analog signal representative of the
residual value (4 mA being zero residual and 20 mA being full scale residual).
PO1: When “PO1” is selected, the analog output will send a 4-20 analog signal representative of the
PID Control Program Process Output (4 mA being zero and 20 mA being PO1 full scale).
pH: When “pH” is selected, the analog output will send a 4-20 analog signal representative of the pH
value (4 mA being zero pH and 20 mA being 14 pH).
Temp: When “Temp” is selected, the analog output will send a 4-20 mA analog signal representative of
the sample water temperature (4 mA being 0º C / 32º F and 20 mA being 50º C / 122º F).
Turb1/Turb2: When Turb1 or Turb2 is selected the analog output will send a 4-20mA analog signal
representative of the corresponding Turbidity reading.
NOTE: The AOX output calibration menus are accessed as detailed in the note on Figure 7.
AOX 4mA Cal: This screen allows for calibration of the AOX 4mA output. Using a meter to read the
output, fi ne adjustments can be made using the and buttons.
AOX 20mA Cal: This screen allows for calibration of the AOX 20mA output. Using a meter to read the
output, fi ne adjustments can be made using the and buttons.
Alarm: This branch accesses the settings for the four alarm relays. (Relay 1, Relay 2, Relay 3, Relay 4)
Alarm Mode: Select “Latching” or “Non-Latching”. A latching relay will require manual
acknowledgement of any alarm condition (by pressing the button on the Main Operation Mode
screen). When Non-Latching is selected, alarms will clear themselves whenever the alarm condition no
longer exists.
Alarm Delay: Enter desired delay time. Any alarm condition must then exist for this period of time
before tripping the relay. This delay can help avoid false alarms and is recommended to be set at 5
seconds or longer.
NOTE: The analyzer is equipped with four alarm relays. Each of these relays can be individually set to
represent any of the following alarm conditions:
1. Low Residual
2. High Residual
3. Turbidity 1 high alarm
4. Turbidity 2 high alarm
5. pH high/low alarm
6. Any alarm
DL: This branch accesses the settings for the optional data logger.
On/Off: Depending on whether the data logger feature is enabled or disabled, this menu will present the
option to change the status.
Data Log Frequency: Whenever the data logger feature is enabled, the frequency with which data is
recorded is adjustable on this menu.
Set New Date/Time: If it is necessary to set or change the date and time in the data logger software,
select “YES” on this menu.
Set Data Log Clock: This menu allows the date and time to be set. Whenever this menu is accessed,
the current date and time must be entered. A confi rmation screen will appear afterward.
19

20