Hanna Instruments HI 710 Series User manual

HI 700 / HI 710 Series
Process,
Panel-mounted,
Microprocessor-based,
Conductivity and TDS
Controllers
Instruction Manual

32
TABLE OF CONTENTS
PRELIMINARY EXAMINATION . . . . . . . . . . . . . . . . . . 4
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . 4
FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . 6
MECHANICAL DIMENSIONS . . . . . . . . . . . . . . . . . . 7
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
SETUP MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
CONTROL MODE . . . . . . . . . . . . . . . . . . . . . . . . . 18
IDLE MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
ANALOG OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . 27
RS 485 COMMUNICATION . . . . . . . . . . . . . . . . . . 29
CALIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
LAST CALIBRATION DATA . . . . . . . . . . . . . . . . . . . . 44
FAULT CONDITIONS AND SELFTEST PROCEDURES . . 45
EXTERNAL FUNCTIONS . . . . . . . . . . . . . . . . . . . . . 48
STARTUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
EC VALUES AT VARIOUS TEMPERATURES . . . . . . . . . 50
PROBE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . 51
ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
CE DECLARATION OF CONFORMITY . . . . . . . . . . . 55
© 2001 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 Product.
This instruction manual has been written for the following
products:
HI 700221-αα
αα
αEC controller with dual setpoint, ON/OFF
and PID controls, analog output.
HI 700222-αα
αα
αEC controller with dual setpoint, ON/OFF
and PID controls, RS485 port.
HI 710221-αα
αα
αEC and TDS controller with dual setpoint,
ON/OFF and PID controls, analog output.
HI 710222-αα
αα
αEC and TDS controller with dual setpoint,
ON/OFF and PID controls, RS485 port.
αα
αα
α = 1 means 115 Vac, 50/60 Hz power supply
αα
αα
α = 2 means 230 Vac, 50/60 Hz power supply
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.

54
• Four different EC working ranges (0 to 199.9μS; 0 to
1999μS; 0 to 19.99mS; 0 to 199.9mS).
• Four different TDS working ranges (0 to 100.0ppm; 0 to
1000ppm; 0 to 10.00ppm; 0 to 100.0ppm) for HI 710
models.
• Possibility to switch to TDS measurements with conversion
factor from 0.00 to 1.00 (HI 710 models only).
• Temperature compensation of the HANNA standard solu-
tions.
• Temperature compensation of the EC and TDS reading with
temperature coefficient ß selectable from 0 to 10%/°C.
• Manual temperature setting when the temperature probe is
not inserted or temperature exceeds the upper range.
• Last calibration data internally recorded (non-volatile EE-
PROM memory): calibration date and time, cell constant,
calibration solution values.
• Input:4-ring EC/TDS probe with cell constant 2.0 ± 10%,
or 4-20mA analog input from a transmitter.
• Output (HI 700221 and HI 710221 only):
- isolated 0-1 mA, 10 KΩmaximum load (optional);
- isolated 0-20 mA, 750 Ωmaximum load (optional);
- isolated 4-20 mA, 750 Ωmaximum load (optional);
- isolated 0-5 VDC, 1 KΩminimum load (optional);
- isolated 1-5 VDC, 1 KΩminimum load (optional);
- isolated 0-10 VDC, 1 KΩminimum load (optional).
• Real time clock.
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, notify
your Dealer or the nearest Hanna Customer Service Center
immediately.
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
HI 700 and HI 710 series are real time microprocessor-
based EC or TDS controllers. They provide accurate
measurements, flexible ON/OFF or proportional control ca-
pabilities, analog input and output, RS485 port, dual setpoint
and alarm signal.
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 17 mm digits and 3 ½ 10 mm
digits.
• LEDs: four LEDs are provided for signaling the energizing
of relay 1 and 2 (yellow LEDs) and alarm relays (a green
and a red LED).
• Relays: 1 or 2 output relays for low conductivity or high
conductivity dosage (COM, NO and NC contacts) and 1
output relay for alarm condition (COM, NO and NC con-
tacts).
• RS485 isolated communication link (HI 700222 and HI
710222 only).
• Calibration and Setup procedures allowed only through
an unlock password.
• Calibration: 2 points with Hanna EC and TDS calibration
solutions.

76
REAR PANEL
1. 6-pin RS485 terminal (HI 700222 and HI 710222 only)
2. Analog Output (HI 700221 and HI 710221 only)
3. Power Supply
4. Alarm Terminal
5. Contact 2 - Second Dosing Terminal
6. Timer
7. Hold
8. Contact 1 - First Dosing Terminal
9. Pt 100 Temperature Sensor connector
10. EC/TDS probe connector
11. Power supply output for external transmitter
12. 4-20 mA input from external transmitter
Unplug the meter before any electrical connection.
MECHANICAL DIMENSIONS
FRONT VIEW SIDE VIEW
FUNCTIONAL DESCRIPTION
FRONT PANEL
1. Liquid Crystal Display
2. SETUP key enters setup mode
3. CFM key confirms current choice (and skips to the next item)
4. CAL key initiates and exits calibration mode
5. 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
6. CAL DATA key last calibration data viewing (enters and exits)
7. 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
8. LCD key exits from setup and reverts back to normal mode (in idle
or control phases with the measurement on the display).
During EC/TDS calibration, it alternates EC/TDS buffer
value and current cell constant on the display. In HI 710
models only, it switches between EC and TDS reading
9. key moves to the next digit/letter (circular solution) when se-
lecting a parameter. Same as key during last calibration
data viewing mode
10. LEDs

98
INSTALLATION
HI 700 and HI 710
series offer a multitude
of possibilities, from
single and dual set-
points to ON/OFF or
PID dosage, isolated
outputs with user-select-
able zoom, bi-directional
RS485, recorder outputs
in mAmps and Volts.
Use the 3-wire Pt 100
temperature sensor to
compensate for the
cable resistance and
have a precise auto-
matic temperature
compensation of the
measurements in long
distance applications.
See the diagram for a
recommended installa-
tion.
SPECIFICATIONS
Ranges 0.0 to 199.9 μS, 0 to 1999 μS
0.00 to 19.99 mS, 0.0 to 199.9 mS
0.0 to 100.0 ppm, 0 to 1000 ppm (HI 710* only)
0.00 to 10.00 ppt, 0.0 to 100.0 ppt (HI 710* only)
-10.0 to 100.0 °C
Resolution 0.1 μS, 1 μS, 0.01 mS, 0.1 mS
0.1 ppm, 1 ppm (HI 710 models only)
0.01 ppm, 0.1 ppm (HI 710 models only)
0.1 °C
Accuracy ±0.5 % F.S. (EC and TDS)
(@20°C/68°F) ±0.5°C (0 to 70°C), ±1°C (outside)
Typical EMC Deviation ±2 % F.S. (EC and TDS) / ±0.5 °C
EC Calibration Automatic or manual at 1 point
Temperature Compensation Automatic or manual, -10 to 100°C with adjustable
temperature coefficient from 0.00 to 10.00%/°C
TDS Factor (HI 710 only) Adjustable from 0.00 to 1.00
Outputs Analog: isolated 0-1 mA, 0-20 mA and 4-20 mA;
0-5 Vdc, 1-5 Vdc and 0-10 Vdc; or digital: RS485
Analog Input 4-20 mA
Setpoint Relay 2 contact outputs SPDT, 5A-250 Vac, 5A-30 Vdc
(resistive load). Fuse protected: 5A, 250V FUSE
Alarm Relay Contact output SPDT, 5A-250 Vac, 5A-30 Vdc
(resistive load). Fuse protected: 5A, 250V FUSE
Power Supply 230 ±10% Vac or 115 ±10% Vac, 50/60 Hz
Power Consumption 15 VA
Over Current Protection 400 mA 250V FAST FUSE
Environment 0 to 50°C (32 to 122°F); RH max 95%
Installation Category II
Enclosure Single case ½ DIN
Dimensions Panel cutout: 140 x 140 mm
Instrument: 144 x 144 x 170 mm
Weight Approximately 1.6 kg. (3.5 lb.)
* Note: actual TDS range for HI 710 models depends on TDS factor set.

1110
If the Pt 100 has more than 2 wires, con-
nect the two wires of one end to pins 7
and 8 (pin 7 is an auxiliary input to com-
pensate for the cable resistance) and one
wire from the other end to pin 6. Leave
the fourth wire unconnected, if present.
Note If the meter does not detect the temperature probe, it will
switch automatically to manual temperature compensation
with the temperature adjustable through the up and down
arrow keys. The “°C” symbol will blink on the LCD.
Note All external cables to be connected to the rear panel should
be ended with cable lugs.
• Analog output: Connect an external recorder with a 2-wire
cable to these terminals (#2 on page 7) paying attention
to the correct polarity. A wide variety of output signals,
either in V or in mA, is available to fit most standards.
• Contact 1 and 2: Connect the dosing devices to these
terminals (#5 and #8 on page 7) in order to activate and
deactivate them according to the selected control param-
eters.
• mA Input: to switch to mA input signal from a
conductivity transmitter (e.g. HI8936, HI98143
or HI98144 series) see setup procedure (code
6). Connect the two signal wires from the trans-
mitter to terminals #12 on page 7, paying at-
tention to the correct polarity.
An unregulated 10 to 30 VDC - 50 mA max.
power supply output (#11 on page 7) is pro-
vided to power the transmitter, if needed.
Once the installation is completed, select the appropriate
working range, the reference temperature (20 or 25°C) and
perform conductivity or TDS calibration as described in this
instruction manual. Set the control parameters according to
the process.
•Power Supply: Connect a 3-wire power cable
to the terminal strip, while paying attention
to the correct live (L), earth (PE) and neu-
tral (N) terminal connections.
Power: 115 Vac -100 mA / 230 Vac - 50 mA.
Live Contact: fused inside 400 mA.
PE leakage current 1 mA; this contact must be con-
nected to ground.
•Conductivity input: the default input is from conductivity
probe. Connect the EC probe to the terminals #10 on
page 7. Connect the cable shield to pin 1, and the other
four wires according to the following table:
Color Pin #
GREEN 2
WHITE 3
RED 4
BLUE 5
•Pt 100 Terminals: these contacts (#9 on page 7) connect
the Pt 100 temperature sensor for automatic temperature
compensation of measurement. The HI7639 EC/TDS probe
has a built-in 3-wire Pt 100 sensor to be connected ac-
cording to the following table:
Color Pin #
GRAY 6
BROWN 7
YELLOW 8.
If using a different Pt 100, separated from the conductivity
probe, connect the cable shield to pin 9, and the other
wires as explained below.
In the case of a 2-wire sensor connect
the Pt 100 to pins 6 and 8, and short
pins 7 and 8 with a jumper wire.

1312
• 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 param-
eters (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.
SETUP MODE
HI 700 and HI 710 offer a multitude of possibilities from
ON/OFF or PID dosage to analog recorder output and from
alarm to selftest features.
The Setup Mode allows the user to set all needed character-
istics 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 value of the pass-
word by the or keys.

1514
Code Valid Values Default PW
14 Relay 1 deviation (D1) 0.5 to 10% f.s. 1% f.s. no
15 Relay 1 reset time 0.1 to 999.9 minutes 999.9 no
16 Relay 1 rate time 0.0 to 999.9 minutes 0.0 no
21 Relay 2 mode (M2) same as relay 1 0 no
22 Relay 2 setpoint (S2) 0.5 to 99.5% full scale 75% f.s. no
23 Relay 2 hysteresis (H2) 0 to 5% f.s. 1% f.s. no
24 Relay 2 deviation (D2) 0.5 to 10% f.s. 1% f.s. no
25 Relay 2 reset time 0.1 to 999.9 minutes 999.9 no
26 Relay 2 rate time 0.0 to 999.9 minutes 0.0 no
30 Relay 3 high alarm (HA) 0.5 to 99.5% full scale 95% f.s. no
HA-HysLA+Hys,Hys=1.5%f.s.,HAS1 or HAS2
31 Relay 3 low alarm (LA) 0.5 to 99.5% full scale 5% f.s. no
LA+HysHA-Hys,Hys=1.5%f.s.,LAS1 or LAS2
32 Proportional control 1 to 30 min 5 no
mode period
33 Maximum relay ON time 10 to 9999 min 60 no
(after which an alarm mode is entered)
34 Alarm mask time 00:00 to 30:00 00:00 no
40 Analog output selection 0: 0-1mA 2 no
1: 0-20 mA
2: 4-20 mA
3: 0-5 VDC
4: 1-5 VDC
5: 0-10 VDC
41 Analog output 0 to 100% full scale 0 no
lower limit (O_VARMIN) (O_VARMIN O_VARMAX - 5% f.s.)
42 Analog output 0 to 100% full scale 100% f.s. no
upper limit (O_VARMAX) (O_VARMIN O_VARMAX - 5% f.s.)
• After confirmation, the selected parameter
is displayed. The user can scroll through
the parameters by pressing CFM.
In order to directly set another param-
eter, press SETUP again and enter the
code or scroll to it by pressing CFM.
The following table lists the setup codes along with the descrip-
tion 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 99 00 no
02 Control enable/disable 0: C.M. disabled 0 no
1: C.M. enabled
03 Range 1: 0.0-199.9 μS (or 100.0 ppm) 4 no
(depends on model) 2: 0-1999 μS (or 1000 ppm)
3: 0.00-19.99 mS (or 10.00 ppt)
4: 0.0-199.9 mS (or 100.0 ppt)
04 Reference Temperature 20°C or 25°C 25°C no
05 Temperature Coefficient 0.00 to 10.00 %/°C 2.00 no
06 Input Selection 0: conductivity probe 0 no
1: 4-20 mA input signal
07 Temperature ATC: Automatic ATC no
compensation User: Manual
08 TDS Factor (HI710 only) 0.00 to 1.00 0.50 no
11 Relay 1 mode 0: disabled 0 no
(M1) 1: ON-OFF high setpoint
2: ON-OFF low setpoint
3: PID, high setpoint
4: PID, low setpoint
12 Relay 1 setpoint (S1) 0.5 to 99.5% full scale 25% f.s. no
13 Relay 1 hysteresis (H1) 0 to 5% f.s. 1% f.s. no

1716
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;
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;
where the minimum deviation (D1 or D2) is 0.5% of the maxi-
mum range value.
Note When a wrong setup value is confirmed,
the controller does not skip to the next setup
item but remains in the current item dis-
playing a flashing “ERROR” indicator un-
til the parameter value is changed by the
user (the same is also true for the setup code selection).
Note 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 EC high setpoint to 10.0
mS the high alarm must be set to a value greater than 10.0
mS first.
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 1998 to 9999 from RTC no
63 Current time 00:00 to 23:59 from RTC no
71 Baud rate (RS485) 1200, 2400, 4800, 9600 9600 no
72 Cleaning timer 0 to 19999 days 0 no
73 Initial cleaning day 01 to 31 01 no
74 Initial cleaning month 01 to 12 01 no
75 Initial cleaning year 1998 to 9999 1998 no
76 Initial cleaning time 00:00 to 23:59 00:00 no
77 Cleaning ON interval 0 to 19999 minutes 0 no
90 Display selftest 0: off 0 yes
1: on
91 Keyboard selftest 0: off 0 yes
1: on
92 EEPROM selftest 0: off 0 yes
1: on
93 Relays and LEDs selftest 0: off 0 yes
1: on
94 Watchdog selftest 0: off 0 yes
1: on
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, “ERROR” blinks on the LCD to prompt
the user. The correct configurations are the following:
If M1=/ 0 then S1HA, S1LA;
If M2=/ 0 then S2HA, S2LA;
If M1= 1 then S1-H1LA;
If M1= 2 then S1+H1HA;

1918
An upper boundary is imposed for dosage time when relays
are energized continuously, i.e. when relay works in ON/
OFF mode or also 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 (high or low conductivity dosage) the
user has to define the following values through setup:
• relay setpoint (μS/mS/ppm value);
• relay hysteresis (μS/mS/ppm 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 EC mea-
sured value (similar graph can be derived for TDS control).
As shown below, a high setpoint relay is activated when the
measured EC exceeds the setpoint and is deactivated when it
is below the setpoint value minus hysteresis.
Such a behavior is suitable to control a high conductivity
dosing pump.
A low setpoint relay as can be seen from the following graphs
is energized when the EC value is below the setpoint and is
de-energized when the EC value is above the sum of setpoint
and the hysteresis. The low setpoint relay may be used to
ON
OFF
Setpoint ECSetpoint –
Hysteresis
CONTROL MODE
The control mode is the normal operational mode for these
meters. During control mode the meter fulfills the following
main tasks:
• converts information from EC/TDS and temperature inputs
to digital values;
• controls relays and generates the analog outputs as deter-
mined by the setup configuration, displays alarm condition;
In HI 710 models it is possible to switch between EC and
TDS reading pressing “LCD”. The TDS value is obtained mul-
tiplying the EC measurement by the TDS factor set through
setup. The HI 700 models display EC only.
The status of the meter is shown by the LED’s on the right.
STATUS LEDs
Control Alarm Alarm LED (green) RelayLED(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 deacti-
vate the control mode definitively, set
CONTROL ENABLE to “0” (item #
02).
RELAY MODES
Once enabled, the relays 1 and 2 can be used in four differ-
ent modes:
1) ON/OFF, high setpoint (low conductivity dosage);
2) ON/OFF, low setpoint (high conductivity dosage);
3) PID, low setpoint (low conductivity dosage);
4) PID, high setpoint (high conductivity dosage).

2120
dition of low or high conductivity solution.
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 derivative
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.
Error
100%
0
Proportional Band
Controller
output
control a low conductivity dosing pump.
P.I.D. CONTROL MODE
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 derivative
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 EC/TDS process controller
behavior. Similar graph may apply to the 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
on 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 ac-
tion only.
The derivative function (rate action) compensates for rapid
changes in the system reducing undershoot and overshoot of
the EC or TDS value.
During PID control, the ON interval is dependent not only on
the error amplitude but even on the previous measurements.
Definitely PID control provides more accurate and stable con-
trol than ON/OFF controllers and it is best suitable in system
with a fast response, quickly reacting to changes due to ad-
t0t0+Tct0+2Tct0+3Tc
ON
OFF
EC
Setpoint +
Hysteresis
Setpoint
EC
RATE ACTION COMPENSATES FOR RAPID CHANGES t

2322
SIMPLE TUNING PROCEDURE
The following procedure uses a graphical technique of ana-
lyzing a process response curve to a step input.
1. Starting from a solution with an EC or TDS value quite
different from the dosed liquid, turn on the dosing device
at its maximum capacity without the controller in the loop
(open loop process). Note the starting time.
2. After some delay (T0) the EC or TDS starts to vary. After
more delay, the EC or TDS will reach a maximum rate of
change (slope). Note the time that this maximum slope
occurs and the EC or TDS value at which it occurs. Note
the maximum slope in EC or TDS per minute. Turn the
system power off.
3. On the chart draw a tangent to the maximum slope point until
intersection with the horizontal line corresponding to the initial
EC or TDS value. Read the system time delay Tx on the time axis.
4. The deviation, Ti and Td can be calculated from the following:
• Deviation = Tx * max. slope (EC/TDS)
• Ti = Tx / 0.4 (minutes)
• Td = Tx * 0.4 (minutes).
5. Set the above parameters and restart the system with the
controller in the loop. If the response has too much over-
shoot or is oscillating, then the system can be fine-tuned
slightly increasing or decreasing the PID parameters one
at a time.
Note Connecting an external device (e.g. chart recorder) to the
controller, the procedure is easier and doesn’t need the use
of hand plotting the process variable (EC or TDS).
The proportional action is set through the setup procedure as
“Deviation” in percent of full scale of the selected range.
Each setpoint has a selectable deviation: D1 for setpoint1
and D2 for setpoint2.
Two further parameters must be provided for both setpoints:
Ti = Kp/Ki, reset time, measured in minutes
Td = Kd/Kp, rate time, measured in minutes.
Ti1 and Td1 will be the reset time and rate time for setpoint1,
while Ti2 and Td2 will be the reset time and the rate time for
setpoint2.
TUNING A PID CONTROLLER
The proportional, integrative, derivative terms must be tuned,
i.e. adjusted to a particular process. Since the process vari-
ables are not typically known, a “trial and error” tuning
procedure must be applied to get the best possible control for
the particular process. The target is to achieve a fast response
time and a small overshoot.
Many tuning procedures are available and can be applied
to the EC/TDS controllers. A simple and profitable procedure
is reported in this manual and can be used in almost all
applications.
The user can vary five different parameters, i.e. the setpoint
(S1 or S2), the deviation (D1 or D2), the reset time, the rate
time and the proportional control mode period Tc(from 1 to
30 minutes).
Note User can disable the derivative and/or integrative action (for
P or PI controllers) by setting Td = 0 and/or Ti = MAX (Ti)
respectively through the setup procedure.

2524
This is an important feature since with most meters the alarm
terminals close only when an abnormal situation arises, how-
ever, due to line interruption, no alarm
is sounded, causing extensive damage.
On the other hand, software is em-
ployed to set off the alarm in abnormal
circumstances, for example, if the dos-
ing terminals are closed for too long a
period. In both cases, the red LED’s will
also provide a visual warning signal.
The Fail Safe mode is accomplished by connecting the exter-
nal alarm circuit between the FS•C (Normally Open) and
the COM terminals. This way, an alarm will warn the user
when EC exceeds the alarm thresholds, during power down
and in the case of a broken wire between the process meter
and the external alarm circuit.
Note In order to have the Fail Safe feature activated, an external
power supply has to be connected to the alarm device.
CONTROL THROUGH ANALOG OUTPUT
Models HI 700221 and HI 710221 have a proportional
analog signal (selectable among 0-1mA, 0-20mA, 4-20mA,
0-5VDC, 1-5VDC and 0-10VDC) at the analog output ter-
minals. With this output, the actual output level amplitude is
varied, rather than the proportion of ON and OFF times
(duty cycle control). A device with analog input (e.g. a pump
with a 4-20 mA input) can be connected to these terminals.
FS•O = NC (Normally Closed)
De-energized Relay
COM
FS•C = NO (Normally Open)
Energized Relay
ALARM RELAY
The alarm relay functions in the following manner:
During alarm condition, the relay is de-energized. When not
in alarm condition, the relay is energized.
Example: High alarm set at 1400 μS
Low alarm set at 600 μS
An hysteresis will eliminate the possibility of continuous se-
quences ‘energizing/de-energizing’ of the alarm relay when
the measured value is close to the alarm setpoint. The alarm
hysteresis amplitude is 1.5% of full scale.
Moreover the alarm signal is generated only after a user se-
lectable time period (alarm mask) has elapsed since the
controlled value has overtaken one alarm threshold. This
additional feature will avoid fake or temporary alarm condi-
tions.
Note If the power supply is interrupted, the relay is de-energized as
if in alarm condition to alert the operator.
In addition to the user-selectable alarm relays, all EC/TDS
controllers are equipped with the Fail Safe alarm feature.
The Fail Safe feature protects the process against critical
errors arising from power interruptions, surges and human
errors. This sophisticated yet easy-to-use system resolves these
predicaments on two fronts: hardware and software. To elimi-
nate problems of blackout and line failure, the alarm function
operates in a “Normally Closed” state and hence alarm is
triggered if the wires are tripped, or when the power is down.

2726
ANALOG OUTPUT
HI 700221 and HI 710 221 models are provided with the
analog output feature.
The output is isolated and can be a voltage or a current.
With the recorder, simply connect the
common port to the ground output and
the second port to the current output
or voltage output (depending on which
parameter is being used) as depicted
aside.
The type (voltage or current) and the range of the output
analog signal is selectable through the jumpers on the power
board.
Configurations of the switch are as follows:
Output Switch 1 Switch 2 Switch 3 Switch 4
0-5 VDC, 1-5 VDC OFF ON – – – –
0-10 VDC ON OFF – – – –
0-20 mA, 4-20 mA – – – – ON – –
0-1 mA – – – – OFF – –
Choice between different ranges with the same configuration
(for example 0-20 mA and 4-20 mA) is achieved via soft-
ware by entering the setup mode and selecting code 40 (see
Setup Mode section for exact procedure).
Factory default is switches 1 and 3 closed (ON) and switches
2 and 4 open (OFF), i.e. 0-20 mA, 4-20 mA and 0-10
VDC.
In any case, contact the nearest Hanna Customer Service
Center for changing of the default configuration.
By default the minimum and maximum values of analog out-
put correspond to the minimum and maximum of the selected
range of the meter. For example, for the HI 700221 with a
selected 0 to 1999 μS range and analog output of 4-20 mA,
the default values are 0 and 1999 μS corresponding to 4
and 20 mA, respectively.
IDLE MODE
Idle mode is entered through setup code 2.
During idle mode the device performs the same tasks as when
it is in control mode except for the relays. The alarm relay is
activated (no alarm condition), the control relays are not
activated while the analog output remains activated.
When the instrument is in idle mode the red and green status
LEDs are on.
Idle mode is useful to disable control actions when the exter-
nal devices are not installed or when the user detects unusual
circumstances.
Control actions are stopped as soon
as the user presses SETUP and enters
the password.
In order to reactivate the control mode, use code 02 of setup
(see “Setup” section). Otherwise, the meter remains in idle
mode.

2928
output matching a different EC or TDS range, for example,
4 mA = 30 mS and 20 mA = 50 mS.
To change the default values, the setup mode must be en-
tered. Setup codes for changing the analog output minimum
and maximum are 41 or 42, respectively. For the exact pro-
cedure, refer to the setup mode section in the manual.
Note The analog output is factory calibrated through software. The
user may also perform the calibration procedure as explained
in the following. It is recommended to perform the output
calibration at least once a year.
Note Analog output resolution is 1.5‰ f.s. with 0.5% f.s. accu-
racy.
Note The analog output is “frozen” when entering the setup or
calibration mode (after password confirmation).
RS 485 COMMUNICATION
HI 700222 and HI 710222 are provided with an RS485
port.
RS485 standard is a digital transmission method that allows
long lines connections. Its current-loop system makes this
standard suitable for data transmission in noisy environments.
Data transmission from the instrument to the PC is possible
with the HI 92500 Windows®compatible application soft-
ware offered by Hanna Instruments.
The user-friendly HI 92500 offers a variety of features such
as logging selected variables or plotting the recorded data. It
also has an on-line help feature to support you throughout
the operation.
HI 92500 makes it possible for you to use the powerful means
of the most diffused spreadsheet programs (Excel©, Lotus
1-2-3©etc.). Simply run your favorite spread sheet and open
the file downloaded by HI 92500. It is then possible to elabo-
rate the data with your software (e.g. graphics, statistical
analysis).
To install HI 92500 you need a 3.5" drive and few minutes
to follow the instructions conveniently printed on the disk’s
label.
Contact your Hanna Dealer to request a copy.
SPECIFICATIONS
The RS485 standard is implemented in with the following char-
acteristics:
Data rate: up to 9600 bps
Communication: Bi-directional Half-Duplex
Line length: up to 1.2 Km typ. with 24AWG cable
Loads: up to 32 typ.
Internal termination: none
Excel©Copyright of “Microsoft Co.”
Lotus 1-2-3©Copyright of “Lotus Co.”
Windows®registered Trademark of “Microsoft Co.”

3130
CONNECTIONS
The connections for the 6-pin RS485 terminal provided (#1
on page 7) are as follows:
There is an internal short between the two A pins and be-
tween the two B pins.
The instrument has no internal line termination. To terminate
the line, an external resistor equal to the characteristic line
impedance (typically 120Ω) must be added at both ends of
the line.
Up to 32 units can be connected to the same RS485 line,
with a total line length of up to 1.2 Km using 24AWG cable.
To minimize electromagnetic interferences, use shielded or
twisted pair cable to connect the units.
Each unit is identified by its process ID number (setup item
“01”).
The controller acts as a “slave” device: it only answers to
commands received from a “master” device (e.g. an indus-
trial PC) connected to the line.
As additional feature, the controller is also
provided with two pins (5V and 0V) in
order to apply the Fail Safe Open Line
protection method. To avoid erroneous
readings in Open-Line conditions, pull-
up and pull-down resistors should be
connected as shown.
The Fail-Safe resistors are connected only to one unit in the
line, and their value depends on the application and char-
acteristic impedance of the connection cable.
The RS485 port is optoisolated from measuring circuit and
power line. The analog output and RS485 port have the same
ground.
RS485 PROTOCOL
The commands sent to the controller must have the following
format:
• 2-digit process ID number
• 3-character command name
• Parameters (variable length, may be null)
• End of command (always the CR character, Hex 0D)
A maximum time interval of 20 ms is allowed between two
consecutive characters of a command.
It is possible to send commands to change the controller
settings or to simply ask information on the controller status.
Following is the complete list of commands available:

3332
Command Parameter Description
CAR null Request calibration data
GET NN Request setup item NN
K 01 null Same as CFM++CAL keys
K 02 null Same as LCD+CAL+SETUP keys
KCD null Same as CAL DATA key
KCF null Same as CFM key
KCL null Same as CAL key
KDS null Same as LCD key
KDW null Same as key
KRG null Same as key
KST null Same as SETUP key
KUP null Same as key
MDR null Request firmware code
ECR null Request EC reading
(in control or idle modeonly)
TDR null Request TDS reading
(HI 710 models only, available in
control or idle mode only)
RNG null Request measure Range
(in control or idle mode only)
TMR null Request temperature reading
PWD NNNN Send the 4-digit password
SET NNPC1C2C3C4C5Set setup item NN to the
PC1C2C3C4C5value
P=+ if value is greater than 0
P=
- if value is less than 0
C1 can be 0 or 1 only
C2C3C4C5 can be 0÷9 or blank
(the command is not available if
the controller is in setup mode)
Note If the controller is not in control or idle mode and the tem-
perature reading is requested through the TMR command,
the controller answers with the last acquired reading when it
was in control or idle mode.
Note After a recognized PWD command is received, the controller
allows a maximum of 1 minute without receiving data, after
which it locks again and a new PWD command is needed to
perform password protected operations.
Following are examples of commands for setup items:
1) “03 SET 22
- 01200<CR>”
This command sets the setup item 22 (relay 2 setpoint) of
a EC controller, identified by the process ID number 03,
to the +12.00 mS value.
2) “01 SET 33+005◊◊<CR>”
This command sets the setup item 33 (max. relay ON
time) of a controller, identified by the process ID number
01, to 5 minutes. The “◊”character means blank.
Once the controller has received a command, it answers
with its 2-digit process ID number followed by:
• ACK (Hex 06)
If the controller recognizes the received command
and performs the requested task;
• STX (Hex 02) , Data , ETX (Hex 03)
If the received command is a request of data;
• NAK (Hex 15)
If the received command is not recognized (e.g. the
syntax is wrong);
• CAN (Hex 18)
If the controller cannot answer the request (e.g. the
password was not sent, the controller is in setup
mode, the setup item is not available in that model,
etc.)

3534
Note The controller answers to the GET command with the same
data format explained in the SET command.
Following are examples of answers:
1) “03<STX>
+ 01200<ETX>”
The controller with process ID number 03 says that its
current setpoint is +12.00 mS.
2) “01<STX>UE71022225<ETX>”
The controller with process ID number 01 says that it is a
HI710222 model with firmware release 2.5.
The minum delay between the last received character and
first character of the answer is 15 ms.
When the controller answers to the ECR, TDR and TMR com-
mands, the reading is sent as ASCII string followed by a
character indicating the control and alarm status of the con-
troller. This character can assume the following values:
• “A”, control and alarm are ON;
• “B”, control and alarm are ON, and need update con-
troller setup (GET commands);
• “C”, control is ON and alarm is OFF;
• “D”, control is ON and alarm is OFF, and need up-
date controller setup (GET commands);
• “N”, control and alarm are OFF;
• “M”, control and alarm are OFF, and need update
controller setup (GET commands);
For example, a possible answer to the TMR command is:
“03<STX>10.7C<ETX>”
meaning that the current temperature reading is 10.7°C, the
control action is active, no alarm condition is present and
controller setup is updated on PC.
“03<STX>10.7D<ETX>”
meaning that the current temperature reading is 10.7°C, the
If asking for last calibration data and the controller was never
calibrated, it answers with “0”; e.g. “01<STX>0<ETX>”.
If the controller was calibrated, it answers with “1” followed
by the calibration data.
The Data field of the answer has the following format:
1<Date><Time><CellCostant>
• Date: DDMMYY (e.g. “170400” for April 17,2000)
• Time: HHMM (e.g. “1623” for 4:23 pm)
• Cell Costant: ASCII string (e.g. “1200”)
The items in the Data field are separated by blanks.
SETTING THE BAUD RATE
The transmission speed (baud rate) can be selected with the
up and down keys; then press the CFM key to store the new
settings.
Available baud rates are: 1200, 2400, 4800 and 9600 bps.
control action is active, no alarm condition is present and
controller setup is modified (must update controller setup for
PC - GET command for setup items).

3736
Offset Calibration
• To perform the EC calibration enter
the calibration mode, by pressing
CAL and entering the password.
• After the correct password is entered,
the control actions stop and the pri-
mary LCD will display the first
calibration value, with the "CAL" in-
dicator blinking. The secondary LCD
displays the temperature.
Note If the wrong password is entered the system reverts back to
normal operation, displaying EC values.
• 0 is the default value for the 1st calibration point. Dry the
conductivity probe and leave it in air.
• Only when the reading is stable the
"CAL" indicator will stop flashing (af-
ter about 30 seconds) and the
"READY" and "CFM" indicators will
start blinking.
• Press CFM to confirm the calibration
point; the primary LCD will display
the second expected buffer value.
If the zero calibration cannot be per-
formed, "ERROR" will blink.
Cell constant calibration
• Select the solution value on the
primary display by pressing 
or if the selected range has
two possibilities (e.g. 5.000
and 12.880 mS).
• Immerse the EC/TDS probe with the temperature sensor in
the selected solution. The level of solution must be higher
than the holes of the probe sleeve. Tap the probe repeat-
edly on the bottom of the beaker and stir to ensure that no
air bubbles are trapped inside the sleeve.
• When the reading is stable, "CAL"
will stop flashing (after about 30 sec-
onds) and the "READY" and "CFM"
indicators will blink.
CALIBRATION
The controller is factory calibrated for temperature as well as
for the analog input and outputs.
The user should periodically calibrate the instrument for EC
or TDS. For greatest accuracy, it is recommended that the
instrument is calibrated frequently.
Before beginning normal operation,it is recommended to stan-
dardize the probe with the Hanna calibration solution close
to the expected sample value and inside the selected range.
EC CALIBRATION
The calibration points are as follows:
Range Calibration point(s)
0.0 to 199.9 μS 84.0 μS
0 to 1999 μS 1413 μS
0.00 to 19.99 mS 5.00 - 12.88 mS
0.0 to 199.9 mS 80.0 - 111.8 mS
The user should select the appropriate range to calibrate (setup
code 03). Calibration must be performed for each range used.
The temperature probe should also be connected to the pro-
cess meter. The meters are equipped with a stability indicator.
The user is also guided with indications on the display during
the calibration procedure.
Initial Preparation
Pour a small quantity of the calibration solution (e.g. 1413 μS)
into a beaker. If possible, use a plastic beaker to minimize
any EMC interference.
For accurate calibration use two beakers containing the same
solution, the first one for rinsing the probe, the second one
for calibration. By doing this, contamination between the so-
lutions is minimized.
To obtain accurate readings, use the calibration solution in
the selected range and closer to the values to be measured.

3938
• Press LCD to display the current cell constant on the pri-
mary LCD (factory default value is 2.000 cm-1).
• Press SETUP key.
• Using , and , enter the probe cell constant (the
value must be between 1.333 and 4.000 cm-1) and con-
firm by pressing CFM.
Note If the entered cell constant value is invalid, the “ERROR” indi-
cator blinks on the LCD.
Note Press SETUP before CFM to exit without changing the cell
constant.
CALIBRATION BUFFER DIRECT SELECTION
This feature allows to set a user-defined calibration point, in
order to perform calibration at a point different from the memo-
rized standards.
• Press CAL to enter calibration mode. The LCD will show 0.
• Press SETUP key.
• Using , and , enter the desired buffer value and
confirm by pressing CFM.
Note Press SETUP before CFM to exit without changes.
Note It is suggested to calibrate the offset before entering the cali-
bration buffer direct selection.
• Press CFM to confirm the calibra-
tion point; if the reading is close to
the selected solution, the meter
stores the reading.
If the reading is not close to the se-
lected solution, "ERROR" will blink.
Note A 2-point calibration is always suggested. However the EC
calibration can also be performed at 1 point. To calibrate
offset only, just press CAL after confirmation (with CFM) of
the zero reading; the meter will return to normal operational
mode. To have the cell constant calibrated first, press the up
or down arrow keys after entering the calibration procedure
to skip to the next possible calibration buffer. In this case,
after confirmation of the cell constant, the meter will ask for
the offset calibration displaying zero on the LCD; press CAL
to exit or calibrate the offset, if desired.
Note The calibration value shown is referenced at 25°C even if the
reference temperature of 20°C has been selected.
Note During calibration, press LCD to display the cell constant
value on the primary display. Press LCD again to return to
calibration buffer visualization.
Note To interrupt the calibration procedure press SETUP to restart
the procedure, or CAL to exit to normal operational mode.
Note If the process meter has never been calibrated or an EE-
PROM reset has occurred, the meter continues to perform
measurements. However, the user is informed of an EC or
TDS calibration requirement by a blinking “CAL” indication
(see “Startup” section).
Note The device must be calibrated within the temperature range
specified for the EC or TDS buffer solution.
CELL CONSTANT DIRECT SELECTION
Whenever the EC/TDS probe cell constant is known, it is
possible to directly calibrate the meter using that value.
• Press CAL to enter calibration mode. The LCD will show
the default offset of 0.