OjyjEGA
ENGINEERING, INC.
AnO.VfEG.4
Operator ’s Manual
Group Company
WARRANTY
OMEGA
of
(1)
coverage on each product. If the unit should malfunction, it must be returned to the factory for evaluation. Our Customer
Service Department will issue an Authorized Return (AR) number immediately upon phone or written request. Upon
examination by OMEGA, if the unit is found to be defective it will be repaired or replaced at no charge. However, this
WARRANTY is VOID if the unit shows evidence of having been tampered with or shows evidence of being damaged as
a result of excessive current, heat, moisture, vibration, or misuse. Components which wear or which are damaged by
misuse are not warranted. These include contact points, fuses, and
THERE ARE NO WARRANTIES EXCEPT AS STATED HEREIN. THERE ARE NO OTHER WARRANTIES, EXPRESSED
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND OF
FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL OMEGA ENGINEERING, INC. BE LIABLE FOR
CONSEQUENTIAL, INCIDENTALOR SPECIAL DAMAGES. THE BUYER ’S SOLE REMEDY FOR ANY BREACH OF
THIS AGREEMENT BY OMEGA ENGINEERING, INC. OR ANY BREACH OF ANY WARRANTY BY OMEGA
ENGINEERING, INC. SHALL NOT EXCEED THE PURCHASE PRICE PAID BY THE PURCHASER TO OMEGA
ENGINEERING, INC. FOR THE UNIT OR UNITS OR EQUIPMENT DIRECTLY AFFECTED BY SUCH BREACH.
warrants this unit to be free of defects in materials and workmanship and to give satisfactory service for a period
13
months from date of purchase. OMEGA Warranty adds an additional one (1) month grace period to the normal one
year product warranty to cover handling and shipping time. This ensures that our customers receive maximum
triacs.
Return Requests/Inquirie s
Direct all warranty and repair requests/inquiries to OMEGA Customer Service Department, telephone number
(203) 359-1660. Before returning any instrument, please contact the OMEGA Customer Service Department to obtain
an authorized return (AR) number. The designated AR number should then be marked on the outside of the return
package.
To avoid processing delays, also please be sure to include:
1. Returnee ’s name, address, and phonenumber.
2. Model and Serial numbers.
3. Repair instructions.
One Omega Drive, Box 4047
Stamford, Connecticut 069074047
(203) 359-1660 Telex: 996404 Cable: OMEGA FAX: (203) 359-7700
OMEGA3 is a registered trademark of OMEGA ENGINEERING, INC.
0
Copyright 1986 OMEGA ENGINEERING, INC. All rights reserved including illustrations. Nothing in this manual may
be reproduced in any manner, either wholly or in part for any purpose whatsoever without written permission from
OMEGA ENGINEERING, INC.
Printed in U.S.A.
1
M446/026
PART I
-
INTRODUCTION
TABLE OF CONTENTS
Page No.
Specification s
General Descriptio n
PART II
1.
2.
3.
PART III
-
INSTALLATION
Unpacking
Mounting
Wiring
-
OPERATION INSTRUCTION
TECHNICAL INFORMATION
1.
Controls
2.
Operation
PART IV
-
CALIBRATION
1.
Calibration interval
2.
Equipment required
3.
Calibration procedure
1
2
2
2
3
&
4
4/s
5
5
5/6
PART
V SERVICE
1.
Block diagram
2.
Table I
3.
Transmitter dimensions input/output connections and
Adjustment pot location
4.
Table II
7
8
9
10
MODEL PHTX-11 SPECIFICATIONS
Spans:
Input Impedance:
Output Current:
Power Supply:
Load Resistor:
Linearity:
Temperature Coefficient:
Accuracy:
Repeatability:
Output meter:
Any 1 thru 14,
jumper programmable
zero and span adjustable
1013
1 x
4 to
12 to
ii
ohm
2onlA
80
VDC
iim+DC>O~~~ONAL
Ez
0 to 3400 ohms
pH*.Ol
02%/OC
f.
(Display
ht.01
3%
digit
and current out)
pH
pHk.01
LC D
Supply Voltage Effect:
Operating Temperature:
R.H.:
Isolation:
Common Mode Rej.:
Temperature Compensation:
.Ol%/Volt
to
+60°C
95%
-10 to
0
600 VDC or peak
-120dB
@
60 Hz
Manual or auto
-l-
PART I
-
INTRODUCTION
General
The
put isolation,
modular construction, programmable span selection,
compensation and a NEMA
The Model PHTX-11 accepts as its input any
description
OMEGAmModel PHTX-11 is a 2-wire
wide power supply range, high input impedance, LCD digital display,
4X
housing as a standard enclosure.
pH/ORP
transmitter featuring input-out-
manual/automatic temperature
pH
probe via a BNC co-axial connector.
It transforms the probe signal to a 4 to 20mA D.C. signal that may be transmitted
over 2-wires to a control location. The signal wires also provide power to the
transmitter.
loop.
Any
The output is monitored by placing a load resistor in the current
D-C.
power supply from 12 to 80 volts may be used.
The input is iso-
lated from the output to prevent accidental damage of sensitive data gathering
equipment at the control location.
The
pH
level is constantly displayed on a 3% digit L.C.D. A push button switch
allows the display to indicate the
mA
output on command.
The user can change the range of output signal by utilizing jumpers on one of
the circuit boards and adjusting the zero and span pots.
pH
can be for the full 0 to 14
pH.
to
7
range or as little as 1
The 4 to 20mA output
pH
unit, for example 6
-
PART II
1.
Unpacking
After unpacking, remove instrument cover,
INSTALLATION
remove shipping ties or clamp.
Note any special instructions included in the package.
2.
Mounting
2.0 Before mounting the signal conditioner enclosure, remove the assembled
circuit boards by removing the two
phillips
head screws in the bottom
of the enclosure.
-
2.1 Conduit Mounting
the appropriate size hubs in the ends of the box (ie:
the unit can be supported by ridged conduit using
l/2"
Cut the threaded male portion to allow room for the circuit board.
2.2 Flat Surface
feet be attached to the box.
feet mounted with
2.3 Pipe Mounting
The
"U"
bolts should bolt to the heavy PVC mounting feet.
-
mounting to a flat surface requires the heavy PVC mounting
The surface should be drilled and the
#lO
screws and nuts.
"U"
attachment to a round pipe requires
-
bolts and nuts.
.
or
3/4").
-2-
2.4 Panel Mounting
mounting requires the PVC mounting feet and four PVC mounting blocks.
The blocks are drilled and tapped for
3.
Wiring
-
refer to Table II for hole sizes and locations.
#lo-24
screws.
This
3. 1
3. 2
3. 3
3. 4
After the enclosure is properly mounted the wires for input, output,
ground and remote temperature sensing should be routed through the en-
closure hubs.
and connected to the circuit board assembly.
These connections should be trimmed to the proper length
The circuit board assembly
should then be placed in the enclosure and fastened to the bottom of
the enclosure with the two
phillips
head screws supplied.
The input probe connector is a BNC jack mounted on the input circuit
board.
Use only a coaxial cable that has isolation around the shield.
The shield is isolated from ground and this isolation should be maintained
for proper operation. For best results,
longer than 10 feet.
Long cables result in slow response because the
the probe cable should not be
probe must charge the cable capacitance through the high probe source
resistance.
The
output vires
are isolated from the input and ground, connections
are made to the terminal strip observing polarity to the terminals marked
-
out.
+,
a load resistor.
The Loop
lead.
at the monitoring location.
from the following equation:
RL).
x
sulting in a
ohms, vo
These wires are to be connected to a D.C. power supply through
The wires can be as long as necessary.
resistor
can be either in the positive or negative power supply
The value of the loop resistor depends on the voltage required
Calculate the required power supply voltage
=
Minimum power supply voltage
12 +
A convenient value for the loop resistor might be 250 ohms, re-
5V
output signal using this as an example: RL
Minimum supply voltage
=
12 +
c.02
x
250)
=
17V.
=
1V
1v
to 5v.
to
c.02
=
250
The maximum supply voltage is 80V.
3. 5
The
temperature probe
is optional.
If the probe is used, it should be
connected to the terminal strip connection marked with the resistor
bol.
The probe cable should be shielded and the shield connected to
the ground terminal.
3. 6
Manual
strip connection marked with a resistor symbol.
the value vs. temperature.
the transmitter,
sistor used should be metal film
temperature compensation requires only a resistor at the terminal
Refer to Table I for
8.66K
An
this value is correct for
resistor is normally supplied with
25'C
compensation.
*50
ppm/'C
or wire wound
-3-
ppm/OC.
f
sym-
The re-
1.
&
-
OPERATING INSTRUCTIONS PART III
TECHNICAL INFORMATION
Controls
mA"
1.1
Display
indicate 0.00
switch is
pH
1abeled"Press
to 14.00
for
pH
when the switch is in the relaxed position.
on the cover.
The display will
When the switch is pressed and held, the display will indicate the output
current to
mA,
normally 4.0
mA
to 20.0
mA.
1.2
"pH
CAL" potentiometer is an offset adjustment for the
input circuit board.
This adjustment allows standardization of different
pH
probe on the
probes, it affects the displayed readout and the output current.
1.3
"Slope" potentiometer is a gain adjustment on the input circuit board.
This adjustment is used to standardize the readings for probes with less
than 100% efficiency,
it affects the displayed readout and the output
current.
1.4
"R19"
potentiometer is a gain adjustment on the output circuit board.
This adjustment is factory set and should not need adjustment in the
field, it affects the displayed
1.5
"ZERO" potentiometer is an offset adjustment on the output board.
adjustment sets the 4
it is used in conjunction with the range switch.
the output current only.
mA output current level for the desired
There is interaction between the "Zero" and
pH
readout only.
The “Zero" pot affects
"Span" pots.
1.6
"SPAN"
adjustment sets the 20
it is used in conjunction with the range switch.
potentiometer is a gain adjustment on the output board.
mA
output current level for the desired
The "Span" pot affects
the output current level only. There is interaction between the "Zero"
"Span" pots.
and
pH
level,
This
pH
level,
This
2.
1.7
Range
jumpers are located on the output board.
user to increase the sensitivity of the output. There are 4 jumper pairs
of pads,
the uppermost position is not used; there are no traces connected
to this pair of pads.
from the
to 14
be added
is added
top,
pH
units.
to obtain a full scale output of 2 to 6
for a full scale output of 1 to 2
Operation
2.1
Initialization
described in the wiring (section
sensor in a known buffer solution and turning the power on.
should indicate the
2.2
Probe standardization
probe in a 7.0
adjustment.when
The choice of a 4.0 or 10.0 is up
These jumpers allow the
pads
second
Jumper
and this
Jumper
#l
Jumper
jumper
#2
is located in the third pair of pads, it may
is located in the pair of
is for full scale output currents of 6
pH
units.
pH
units.
of the transmitter consists of making the connections
II-31
of this manual and placing the
The display
pH
value of the buffer solution.
"pH
is accomplished by adjusting
pH
buffer solution
the probe is in a
for a reading of 7.0 and the "Slope"
4.0
pH
or a
iO.0
CAL" with the
buffer solution.
to the user.
-4-
#3
2.3 Test the display
indicate
-
PART IV
CALIBRATION
by pressing the display switch.
mA
and the decimal point should shift one place to the right.
The display should
The recommended calibration interval
normal operating conditions,
and assuming the sensor is in good condition.
for the transmitter is six months under
This system may need adjustment to compensate for reduced efficiency of the
sensor before the calibration interval.
Equipment Required
2.1
pH
Simulator or a
2.2 Precision digital
2.3 D.C. power supply
2.4 Load resistor 250
millivolt source.
multimeter.
24 to 30 volts.
ohm or 500 ohm.
Calibration Procedure
3. 1
Connect the equipment
as shown in block diagram.
Use an
8.66K
resistor
for manual temperature compensation at the terminals with the resistor
(25'C
symbol
compensation).
Refer to Table I for resistance values and
input millivolt values for other temperatures.
3. 2
Before making any adjustments,
range position (Range
#l>.
the-output is in an-over current condition (ie:
the output jumper should be in the full
Input adjustments should not be made while
greater than
2OmA).
Remove the cover from the range switch and turn all switches "Off".
3. 3
"pH
CAL"
adjustment is made with the input at zero volts from the
millivolt source or a
the display reads 7.00.
3. 4
"SLOPE"
pH
Simulator.
adjustment is made with the input at
millivolt source is used.
3. 5
Output ranging
1.7, they are used in conjunction with the Span and Zero adjustments.
i/l
RANGE
is with Jumper
jumper in place.
units,
mA
point at the lowest
20
for spans of less than 14
mA
point at the highest
sensitive and interactive,
justments in turn with small changes.
#2
RANGE
is with jumpers
for a span of 2
pH
of
"7"
on the
pH
Simulator.
"14"
Adjust the pot
pH
on the
Refer to Table I for the millivolt equivalent if a
Ad,just
"SloPe"
for a reading of 14.00.
is accomplished with the jumpers described in Section
#l
in place.
The PHTX-11 is shipped with this
The output is adjustable for a span of 6 to 14
pH,
the "Zero" adjust sets for the 4
pH
point of the range, and the "Span" sets the
pH
point of the range.
The adjustments are
do not attempt large changes, work both ad-
The output is adjustable
to
6
pH
units.
fl
and
112
in place.
until
pH
-5-
The output is adjustable
PII
simulator
for a span of 1 or 2
3.6 SPAN
them.
#3
#2,
and
pH
units.
al,
#3
is with jumpers RANGE
h
ZERO adjustments interact and require going back and forth between
Connect a millivolt source,
in place.
or preferably a
at the input, a resistor at the temperature compensation terminals.
(Refer to Table I for the correct resistor and millivolt values).
mA
the "Zero" for 4
mA
and the "Span"
for 20
at the desired
levels.
pH
Adjust
-6-
<
I
---_-_----!-!
‘i_iI__l
-
-7
TABLE
I
Temp.
oH mv.
0
O'C
+379.3
I
2
3
1
5
6
8
9
10 -162. 6
11 -216. 8
12 -270. 1
13 -325. 1
14 -379. 3
Temp.
Comp.
Res.
1-270.1
+216.8
+162.6
+108.4
-
54.1 9
-108. 4
20.27K
2s”c
mv.
+414-o
+354.9+325.1
+295.a
‘236. 6
+177.5
+i18.3
+
59.15 + 62.13 + 54.19
0
-
59.15
-118.3
-177. 5 -186. 4
-236. 6
-295. 8 -310. 7
-354. 9
-414. 0 -434.9
4o”c
mv. mv.
+434.9
+372.8
+310.7
+248.5
+186.4
+124.2
-
62.13
-124. 2
-248. 5 -256. 5
-372. 8
5.94K8.66K
50°C
mv.
+448-a
+384.7
+320.6
+256.5
+192.-l
+12a.
-
-128. 2 -136. 2
-192. 4
-320. 6 -340. 5
-384. 7 -408. 5
-4-4-8.8
+
64.12
64.12
+476.6
+408.5
+340.5
i272. 4
+204.3
2
+136.2
+ 68.0 9
-
68.0 9
-204. 3 -216. 2 -222. 1
-272. 4 -288. 2
-476. 6
3.08K4.74K
9o”c7o”c
mv.
+504.4
+432.3
~360.3
1-288.2
t-216.2
+144.1
+
72.0 5
-
72.0 5
-144. 1
-360.3 ,
-432. 3 -444. 2
-504. 4
100°C
mv.
+518.2
+444.2
+370.2
+296.1
+333
___.L
+i48.1
+ 74.0 3
-
74.0 3
-148.1
-296. 1
-370. 2
-518.2
1.98K
0
1.58K
.
-a-
-9
b
v-
1
.t7’
DIA.
HOLE
TABLE II
PAN
EL
CUT-OUT
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One Omega Drive, Box 4047
Stamford, Connecticut
(203)
Group
359-1660 Telex: 996404 Cable: OMEGA FAX: (203) 359-7700
Cornpuny
06907-0047
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