Hanna Instruments HI 21 Series User manual

HI21 & HI22 Series
Wall-mounted,
Microprocessor-based
pH and ORP Controllers
Instruction Manual

2
© 2002 Hanna Instruments
All rights are reserved. Reproduction in whole or in part is prohibited without the
written consent of the copyright owner.
Dear Customer,
Thank you for choosing a Hanna Instruments Product.
Please read this instruction manual carefully before using the
instrument. It will provide you with the necessary information
for the correct use of the instrument, as well as a precise
idea of its versatility.
If you need additional technical information, do not hesitate
to e-mail us at [email protected].
These instruments are in compliance with the directives.
MODELS
The models HI21XYZ are pH controllers, while the models
HI22XYZ are ORP controllers.
HI21111 pH Controller with single setpoint, ON/OFF
control, analog output
HI21211 pH Controller with dual setpoint, ON/OFF
control, analog output
HI21221 pH Controller with dual setpoint, propor-
tional and ON/OFF controls, analog output
HI21222 pH Controller with dual setpoint, propor-
tional and ON/OFF controls, RS485 output
HI21523 pH Controller with control through analog
output, proportional and ON/OFF controls,
analog and RS485 outputs
HI22111 ORP Controller with single setpoint, ON/OFF
control, analog output
HI22122 ORP Controller with single setpoint, propor-
tional and ON/OFF controls, RS485 output

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TABLE OF CONTENTS
PRELIMINARY EXAMINATION ..................4
GENERAL DESCRIPTION......................4
FUNCTIONAL DESCRIPTION ..................6
MECHANICAL DIMENSIONS. . . . . . . . . . . . . . . . . . . 7
SPECIFICATIONS HI21 & HI22.................8
INSTALLATION .............................9
SETUP MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
CONTROL MODE .........................17
IDLE MODE ..............................25
ANALOG OUTPUT .........................26
RS485 COMMUNICATION & DATA LOGGING ....28
CALIBRATION ............................35
LAST CALIBRATION DATA ....................48
START-UP ................................51
FAULT CONDITIONS AND SELFTEST PROCEDURES . 52
pH VALUES AT VARIOUS TEMPERATURES .........56
ELECTRODE CONDITIONING AND MAINTENANCE 57
TAKING REDOX MEASUREMENTS ..............61
ACCESSORIES ............................63
WARRANTY ..............................69
CE DECLARATION OF CONFORMITY...........70

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PRELIMINARY EXAMINATION
Remove the instrument from the packing material and exam-
ine it carefully to make sure that no damage has occurred
during shipping. If there is any noticeable damage, please
contact your local Hanna Instruments Office.
Note Save all packing materials until you are sure that the instru-
ment functions correctly. Any damaged or defective items
must be returned in their original packing materials together
with the supplied accessories.
GENERAL DESCRIPTION
The product is a real time microprocessor-based pH/ORP
controller. It provides accurate measurements, flexible
ON/OFF, proportional or PID control capabilities and dual
alarm signals.
The system is composed of a case inside which the signal
conversion circuitry, the microprocessor circuitry and the
output power drivers are contained.
MAIN FEATURES OF DIFFERENT MODELS
• Display: large LCD with 4 ½ 13 mm digits and 3 ½ 7.7
mm digits.
• LEDs: three (HI22) or four (HI21) LEDs are provided for
signaling the energizing of relay 1 (a yellow LED), relay
2 (a yellow LED in HI21 Series only) and alarm relays (a
green and a red LED).
• Relays: Electromechanical type, working through NO,
COM and NC contacts; 1 or 2 output relays for acid or
base dosage; 1 output relay for alarm condition.
• RS485 isolated communication link.
• Calibration and Setup procedures allowed only through
an unlock password.
• Calibration: for HI21 series at 1, 2 or 3 points with
pH4.01, 7.01 and 10.01 buffers; for HI22 series in 1
or 2 points at 0, 350 and 1900 mV.
• Temperature compensation of the Hanna Instruments
standard buffers (for HI21 series only).

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• Temperature compensation of the pH reading (for HI21
series only).
• Manual temperature setting when the temperature probe
is not inserted or temperature exceeds the upper range.
• Internally recorded last calibration data (non-volatile EE-
PROM memory): calibration date and time, pH offset, pH
slopes, number of calibration points and correspondent
pH values (for HI21 series only) or calibration date and
time and the mV calibration points used (for HI22 series
only).
• Input: pH electrode with BNC connector.
• ±5 Vdc output for amplified electrodes (max 10 mA).
• Output:
- isolated 0-1 mA, 10 Kmaximum load (optional);
- isolated 0-20 mA, 750 maximum load (optional);
- isolated 4-20 mA, 750 maximum load (optional);
- isolated 0-5 Vdc, 1 Kminimum load (optional);
- isolated 1-5 Vdc, 1 Kminimum load (optional);
- isolated 0-10 Vdc, 1 Kminimum load (optional).
• Real time clock.

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FUNCTIONAL DESCRIPTION
FRONT PANEL
1. Liquid Crystal Display
2. LCD key exits from setup and calibration modes and reverts back to
normal mode (in idle or control phases with the measure-
ment on the display). In HI21 series, during pH calibration,
alternately displays pH buffer value or current temperature
3. CAL DATA key last calibration data viewing (enters and exits)
4. SETUP key enters setup mode
5. CAL key initiates and exits calibration mode
6. key increases the blinking digit/letter by one when selecting
a parameter. Advances forward while in last calibration
data viewing mode. Increases the temperature setting when
temperature probe is not inserted
7. key moves to the next digit/letter (circular buffer) when selecting
a parameter. Same as key during last calibration data
viewing mode
8. key decreases the blinking digit/letter by one when selecting
a parameter. Reverts backward while in last calibration
data viewing mode. Decreases the temperature setting
when temperature probe is not inserted
9. CFM key confirms current choice (and skips to the next item)
10. BNC Socket
11. LEDs

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CONNECTIONS PANEL
1. 4-pin RS485 terminal (not for HI21XY1 and HI22XY1)
2. Analog output (not for HI21XY2 and HI22XY2)
3. Connections for Pt 100 temperature sensor
4. ±5V power supply output
5. Connection for Potential Matching Pin
6. Connection for electrode reference
7. Power supply input (1 Potential Earth, 2 Neutral, 3 Line)
8. Alarm terminal (1 F.S. Closed, 2 COM, 3 F.S. Open)
9. Relay 1 - first dosing terminal (not for HI21523) - (1 Normally Open, 2 COM,
3 Normally Closed)
10. Relay 2 - second dosing terminal (HI212XY models only) - (1 Normally Open,
2 COM, 3 Normally Closed)
Unplug the meter before starting any electrical connections.
FRONT VIEW BOTTOM VIEW

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SPECIFICATIONS HI21 & HI22
Range
0.00 to 14.00 pH (HI21 series only)
±2000 mV (HI22 series only)
-9.9 to 120.0 °C
Resolution
0.01 pH (HI21 Series only)
1 mV (HI22 Series only)
0.1 ˚C
Accuracy
(@20 °C/68 °F)
±0.02 pH (HI21 Series only)
±2 mV (HI22 Series only)
±0.5 ˚C
Typical EMC
Deviation
±0.05 pH (HI21 Series only)
±4 mV (HI22 Series only)
1.0 ˚C
Analog Output 0 to 1 mA, 0 to 20mA, 4 to 20mA
0 to 5 Vdc, 1 to 5 Vdc, 0 to 10 Vdc
Digital Output RS485
Power Supply Input ±5V (for amplified electrodes)
Power Supply ‘‘-1’’ models: 115 ±10% Vac, 50/60 Hz
‘‘-2’’ models: 230 ±10% Vac, 50/60 Hz
Power Consumption 15 VA
Over Current Protection 450 mA, 250V, FAST FUSE
Relay 1 and 2
Electromechanical relay SPDT contact outputs,
5A- 250 Vac, 5A- 30 Vdc (resistive load)
(HI211YZ, HI212YZ and HI221YZ)
Fuse protected: 5A, 250V FAST FUSE
Alarm Relay
Electromechanical relay SPDT contact output,
5A- 250 Vac, 5A- 30 Vdc (resistive load)
Fuse protected: 5A, 250V FAST FUSE
Environment 0 to 50˚C (32 to 122 ˚F)
RH max 85% non-condensing
Protection IP54
Dimensions 221 x 181 x 86 mm (8.7 x 7.1 x 3.4’’)
Weight approximately 1.4 kg. (3.1 lb.)

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INSTALLATION
HI21 and HI22 offer
a multitude of possibili-
ties, from single and dual
setpoints to ON/OFF,
proportional or PID dos-
age, isolated outputs with
user-selectable zoom,
bidirectional RS485, re-
corder outputs in mAmps
and Volts.
In addition, HI21 and
HI22 are both equipped
with the exclusive differen-
tial input.
In a system with poor
grounding, it is possible
to have a ground cur-
rent flowing through the
reference junction. This
can cause a rapid deg-
radation of the electrode.
The Hanna Instruments
differential input reduces
the likelihood of ground
loops.
See the diagram for a rec-
ommended installation.

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• Power Supply: Connect a 3-wire power cable
to the terminal strip, while paying attention to
the correct line (L), earth (PE) and neutral (N)
terminal connections.
Power: 115VAC - 100 mA / 230VAC - 50 mA.
Line Contact: fused inside 400 mA.
PE must be connected to ground; leakage current 1 mA.
• Electrode: Connect the pH or ORP electrode to the BNC
socket (#10 at page 6).
To benefit from the differential input, connect the proper
electrode wire (if available)
or a cable with a potential
matching pin (grounding bar) to the relevant terminal
(#5 at page 7).
Note When it is not possible to immerse the Potential Matching Pin
together with the pH electrode in the solution, disable the
differential input by connecting the Connection for Potential
Matching Pin (#5 page 7)
with the Connection for
Electrode Reference (#6 on
page 7) with a jumper wire.
• Pt 100 Terminals: these contacts (#3 at page 7) connect
the Pt 100 temperature sensor for automatic temperature
compensation of pH measurement. In the case of shielded
wire, connect the shield to pin 4.
In the case of a 2-wire sensor
connect the Pt 100 to pins 1 and
3, and short pins 2 and 3 with a
jumper wire.
If the Pt 100 has more than 2 wires,
connect the two wires of one end to
pins 2 and 3 (pin 2 is an auxiliary
input to compensate for the cable resistance) and one wire
from the other end to pin 1. Leave the
fourth wire unconnected, if present.
• Power Supply Output: these terminals
provide +5V and -5V DC (max current: 10 mA) signals
to supply power to amplified electrodes.
Note All cables connected to the panel should end with cable
lugs.

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SETUP MODE
HI21 and HI22 offer a multitude of possibilities from
ON/OFF, proportional or PID dosage to analog recorder
output and from alarm to selftest features.
The Setup Mode allows the user to set all needed charac-
teristics of the meter.
The setup mode is entered by pressing SETUP
and entering the password when the device is
in idle or control mode.
Generally speaking, if the password is not inserted the user
can only view the setup parameters (except for password)
without modifying them (and the device remains in control
mode). An exception is certain setup items, or flags, which
can activate special tasks when set and confirmed.
Each setup parameter (or setup item) is assigned a two-
digit setup code which is entered and displayed on the
secondary LCD.
The setup codes can be selected after password and CFM
are pressed. When CFM is pressed, the current setup item
is saved on EEPROM and the following item is displayed.
Whenever LCD is pressed, the de-
vice reverts back to control mode.
The same is true when CFM is
pressed on the last setup item.
The possible transitions in setup mode are the following:
ENTERING THE PASSWORD
• Press SETUP to enter the setup mode. The LCD will display
“0000” on the upper part and “PAS” on the lower. The
first digit of the upper part of the LCD will blink.
• Enter the first digit of the password by the or keys.

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• Then confirm the displayed digit with
and move to the next one.
• When the whole password has been
inserted, press CFM to confirm it.
Note The default password is set at “0000”.
• The LCD will display “SET” on the
upper part and “c.00” on the lower,
allowing the user to edit setup pa-
rameters (see table below).
• Enter the code of the parameter you want to set, using the
arrow keys as per the password procedure above (e.g.
41).
• Confirm the code by pressing CFM and the default or
the previously memorized value will be displayed with the
first digit blinking.
Note When the password is not inserted or a wrong password is
confirmed, the display will only show the previously memo-
rized value, without blinking (read only mode). In this case,
the value cannot be set. Press LCD and start again.
• Enter the desired value using the arrow keys and then
press CFM.

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• After confirmation, the selected param-
eter is displayed. The user can scroll
through the parameters by pressing
CFM.
In order to directly set another pa-
rameter, press SETUP again and
enter the code or scroll to it by press-
ing CFM.
The following table lists the setup codes along with the
description of the specific setup items, their valid values
and whether password is required to view that item (“PW”
column):
Code Valid Values Default PW
00 Factory ID 0 to 9999 0000 no
01 Process ID 0 to 9999 (models w/o RS485)
0 to 99 (models with RS485)
0000
00
no
no
02 Control
enable/disable
0: C.M. disabled
1: C.M. enabled
0 no
11 Relay 1 mode (M1)
for HI21523 only:
0: disabled
1: ON-OFF high setpoint
2: ON-OFF low setpoint
3: PID, high setpoint
4: PID, low setpoint
0: disabled
1: PID, high setpoint
2: PID, low setpoint
0 no
12 Relay 1 setpoint (S1) 0.00 to 14.00 pH
-2000 to 2000 mV
8.00 pH
500 mV
no
13 Relay 1 hysteresis (H1) 0.00 to 14.00 pH
0 to 4000 mV
1 pH
50 mV
no
14 Relay 1 deviation (D1) 0.50 to 14.00 pH
25 to 4000 mV
1 pH
50 mV
no
15 Relay 1 reset time
(HI21523 only)
0.1 to 999.9 minutes 999.9 mins no
16 Relay 1 rate time
(HI21523 only)
0.0 to 999.9 minutes 0.0 mins no
21* Relay 2 mode (M2) same as relay 1 0 no
22* Relay 2 setpoint (S2) 0.00 to 14.00 pH
-2000 to 2000 mV
6.00 pH
-500 mV
no
* Available only in models with two relays

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Code Valid Values Default PW
23* Relay 2 hysteresis (H2) 0.00 to 14.00 pH
0 to 4000 mV
1 pH
50 mV
no
24* Relay 2 deviation (D2) 0.50 to 14.00 pH
25 to 4000 mV
1 pH
50 mV
no
25* Relay 2 reset time
(HI21523 only)
0.1 to 999.9 minutes 999.9 mins no
26* Relay 2 rase time
(HI21523 only)
0.0 to 999.9 minutes 0.0 mins no
30 Relay 3 high alarm (HA) 0.00 to 14.00 pH
-2000 to 2000 mV
HA>LA, HA>S1 or HA>S2
9.00 pH
600 mV
no
31 Relay 3 low alarm (LA) 0.00 to 14.00 pH
-2000 to 2000 mV
LA<HA, LA<S1 or LA<S2
5.00 pH
-600 mV
no
32 Proportional control mode
period
1 to 30 min (not for HI21523)
5 s to 30 min (HI21523 only)
5 min
30 s
no
no
33 Maximum relay ON time 1 to 60 min (HI21523 only)
10 to 9999 min (not for HI21523)
(after which an alarm mode is
entered)
60
60
no
no
34 Alarm mask time
(HI21523 only)
00:00 to 30:00 (mm:ss) 00:00 no
40 Analog output selection 0: 0-1 mA
1: 0-20 mA
2: 4-20 mA
3: 0-5 VDC
4: 1-5 VDC
5: 0-10 VDC
2 no
Note: this parameter refer to internal hardware configuration of the instrument. To change if from the
factory setting, see page 26.
41 Analog output lower limit
(O_VARMIN)
0.00 to 13.00 pH
-2000 to 2000 mV
(0_VARMIN<0_VARMAX-(1.00 pH
or 50 mV))
0.00 pH
-2000 mV
no
42 Analog output
upper limit (O_VARMAX)
1.00 to 14.00
-2000 to 2000 mV
(0_VARMIN<0_VARMAX-(1.00 pH
or 50 mV))
14.00 pH
2000 mV
no

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Code Valid Values Default PW
60 Current day 01 to 31 from RTC no
61 Current month 01 to 12 from RTC no
62 Current year 1997 to 9999 from RTC no
63 Current time 00:00 to 23:59 from RTC no
71 Baud rate 1200, 2400, 4800, 9600 9600 (RS485) no
90 Display selftest 0: off
1: on
0 yes
91 Keyboard selftest 0: off
1: on
0 yes
92 EEPROM selftest 0: off
1: on
0 yes
93 Relays and LEDs selftest 0: off
1: on
0 yes
94 Watchdog selftest 0: off
1: on
0 yes
99 Unlock password 0000 to 9999 0000 yes
Note The process controller automatically checks to ensure that
the entered data matches other related variables. If a wrong
configuration is entered, “WRONG” blinks on the LCD to
prompt the user. The correct configurations are the follow-
ing:
If M1=/ 0 then S1<HA, S1>LA;
If M2=/ 0 then S2<HA, S2>LA;
For models other than HI 21523:
If M1= 1 then S1-H1>LA;
If M1= 2 then S1+H1<HA;
If M1= 3 then S1+D1<HA;
If M1= 4 then S1-D1>LA;
If M2= 1 then S2-H2>LA;
If M2= 2 then S2+H2<HA;
If M2= 3 then S2+D2<HA;
If M2= 4 then S2-D2>LA;
If M1= 1 and M2 = 2
then S1-H1>S2+H2, S2>LA, HA>S1;
If M1 = 2 and M2 = 1
then S2-H2>S1+H1, S1>LA, HA>S2;
If M1 = 3 and M2 = 2
then S1>S2+H2, S2>LA, HA>S1+D1;

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If M1 = 2 and M2 = 3
then S1+H1<S2, S1>LA, HA>S2+D2;
If M1 = 4 and M2 = 1
then S1<S2–H2, S1–D1>LA, HA>S2;
If M1 = 1 and M2 = 4
then S1–H1>S2, S2–D2>LA, HA>S1;
If M1 = 3 and M2 = 4
then S1>S2, S2–D2>LA, HA>S1+D1;
If M1 = 4 and M2 = 3
then S2>S1, S1–D1>LA, HA>S2+D2;
For HI 21523 only:
If M1 = 1 then S1+D1<HA;
If M1 = 2 then S1–D1>LA;
where the minimum deviation (D1 or D2) is 0.5 pH (for
HI21) or 25 mV (for HI22).
Note The password cannot be viewed when SETUP is pressed
without entering the original password first. The default
password is set at “0000”. In the event that the user forgets
the password, this can be reset to “0000” by pressing and
holding CFM and then pressing LCD and CAL DATA at the
same time when the pH controller is in normal operating
mode (idle or control with measurement displaying).
Note When a wrong setup value is con-
firmed, the pH controller does not
skip to the next setup item but remains
in the current item displaying a flash-
ing “WRONG” indicator until the
parameter value is changed by the user (the same is also
true for the setup code selection). In some circumstances,
the user cannot succeed in setting a parameter to a desired
value if the related parameters are not changed beforehand;
e.g. to set a pH high setpoint to 10.00 the high alarm must
be set to a value greater than pH10.00 first.
For code numbers 40, 41, 42, the output is related to pH
or mV units depending on the model (pH process meters
or mV process meters). Items 41 and 42 are not available
in HI215YZ .

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CONTROL MODE
The control mode is the normal operational mode for these
meters. During control mode HI21 and HI22 fulfill the fol-
lowing main tasks:
• convert information from pH/ORP and temperature inputs
to digital values;
• control relays and generate the analog outputs as deter-
mined by the setup configuration, display alarm condition;
• RS485 management (if the feature is included).
In addition, HI21 and HI22 can log working data through
RS485 connection. This data includes:
• pH, mV and oC measured values;
• last calibration data;
• setup configuration (also from PC).
The status of the meter is shown by the LED’s on the right
STATUS LEDs
Control Alarm Alarm LED (green) Relay LED (yellow) Red LED
OFF --- ON OFF ON
ON OFF ON ON or OFF OFF
ON ON OFF ON or OFF Blinking
Meter exits control mode by pressing SETUP or CAL and
confirming the password. Note that this command generates
a temporary exit. To deactivate the
control mode definitively, set CON-
TROL ENABLE to “0” (item # 02).
RELAY MODES
Once enabled, the relays 1 and 2 can be used in four
different modes:
1) ON/OFF, high setpoint (acid dosage) (not for HI21523);
2) ON/OFF, low setpoint (base dosage) (not for HI21523);
3) Proportional or PID (HI21523 only), low setpoint (base
dosage, if available);
4) Proportional or PID (HI21523 only), high setpoint (acid
dosage, if available).

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An upper boundary is imposed for acid/base dosage time
when relays are energized continuously, i.e. when relay
works in ON/OFF mode or in PID mode but in the latter
case only if the relay is always ON. This parameter can be
set through setup procedure. When the maximum boundary
is reached, an alarm is generated; device stays in alarm
condition until relay is de-energized.
ON/OFF CONTROL MODE
Either for mode 1 or 2 (base or acid dosage) the user has
to define the following values through setup:
• relay setpoint (pH/mV value);
• relay hysteresis (pH/mV value).
Connect your device to the COM
and NO (Normally Open) or NC
(Normally Closed) terminals.
The ON relay state occurs when relay is energized (NO and
COM connected, NC and COM disconnected).
The OFF relay state occurs when relay is de-energized (NO
and COM disconnected, NC and COM connected).
The following graphs show relay states along with pH mea-
sured value (similar graph can be derived for mV control).
As shown below, a high setpoint relay is activated when the
measured pH exceeds the setpoint and is deactivated when
it is below the setpoint value minus hysteresis.
Such a behavior is suitable to control an acid dosing pump.
A low setpoint relay as can be seen from the following
graphs is energized when the pH value is below the setpoint
and is de-energized when the pH value is above the sum
of setpoint and the hysteresis. The low setpoint relay may
be used to control an alkaline dosing pump.

19
P.I.D. CONTROL MODE (HI21523 ONLY)
PID control is designed to eliminate the cycling associated
with ON/OFF control in a rapid and steady way by means
of the combination of the proportional, integral and deriva-
tive control methods.
With the proportional function, the duration of the activated
control is proportional to the error value (Duty Cycle Control
Mode): as the measurement approaches setpoint, the ON
period diminishes.
The following graph describes the pH process controller
behavior. Similar graph may apply to the mV controller.
During proportional control the process controller calculates
the relay activation time at certain moments t0, t0+Tc, t0+2Tc
etc. The ON interval (the shaded areas) is then dependent
to the error amplitude.
With the integral function (reset), the controller will reach a
more stable output around the setpoint providing a more
accurate control than with the ON/OFF or proportional
action only.
The derivative function (rate action) compensates for rapid
changes in the system reducing undershoot and overshoot
of the pH value.
During PID control, the ON interval is dependent not only to
the error amplitude but even to the previous measurements.
Definitely PID control provides more accurate and stable
control than ON/OFF controllers and it is best suitable in
system with a fast response, quickly reacting to changes
due to addition of acid or base solution.

20
An example of how the response overshoot can be improved
with a proper rate action setting is depicted in the following
graphic.
PID TRANSFER FUNCTION
The transfer function of a PID control is as follows:
Kp + Ki/s + s Kd = Kp (1 + 1/(s Ti) +s Td)
with Ti = Kp/Ki, Td = Kd/Kp,
where the first term represents the proportional action, the
second is the integrative action and the third is the deriva-
tive action.
Proportional action can be set by means of the Proportional
Band (PB). Proportional Band is expressed in percentage of the
input range and is related to Kp according to the following:
Kp = 100/PB.