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9 SIMPLE FAULT FINDING
9.1 Error Messages
If erroneous or unexpected results are obtained the fault may
be indicated by an error message – see Table 9.1. However
some faults may cause problems with instrument calibration or
give discrepancies when compared with independent
laboratory measurements.
E
r r
r o
M
e
s
s
a
g
e
F
A
U
L
T
Y
P
T
1
0
0
T
e
m
p
e
a r
c
o
n
n
e
t c
F
A
U
L
T
Y
M
O
D
U
L
E
T
h
e
c
o
n
N
V
M
E
M
O
R
Y
T
h
e
c
o
n
E
R
R
O
R
n
t o
b
e
e
n
*
T
o
e r
t c
y f i
h t
e
a f
u
, t l
s
w
c t i
h
o
, f f
a
g
i a
. n
f I
h t
e
a f
u
t l
p
e
s r
s i
s t
c
o
Table 9.1 Error Messages
9.2 No Response to Conductivity Changes
The majority of problems are associated with the conductivity
cell, which must be cleaned as an initial check. It is also
important that all program parameters have been set correctly
and have not been altered inadvertently – see Section 7.
If the above checks do not resolve the fault:
a) Check that the instrument responds to a resistance input.
Disconnect the conductivity cell cable and connect a
suitable resistance box directly to the transmitter input –
see Section 4.3 or 4.4. Check that the instrument displays
the correct values as set on the resistance box using
Table 9.2 below or the expression:
6
K x 10
R =
G
Where:
R = equivalent resistance
K = cell constant
G = conductivity
C
o
n
d
u
c
i t
i v
y t
0
0 .
5
µ
S
c /
m
(
G
)
Ω
0
0 .
5
5
9
0
9
0 .
9
1
k
Ω
0
1 .
5
0
0
k
Ω
0
5 .
1
0
0
k
Ω
1
5
0
k
Ω
5
1
0
k
5 Ω
1
0
k
1 Ω
5
0
k
Ω
1
0
0
5
0
0
Ω
5
0
0
1
0
0
1
0
0
0
–
5
0
0
0
–
1
0
0
0
0
–
Table 9.2 Conductivity Readings for Resistance Inputs
P
o
s
s
b i
e l
C
a
u
s
e
u t
e r
c
o
m
p
e
n
s
t a
r o
a /
s s
o
c
a i
e t
d
o i
n
s
a
e r
i e
h t
r e
o
p
e
n
s /
h
o
t r
i c
c r
u
. t i
d
u
c
v i t
y t i
n i
p
t u
m
o
d
u
e l
m
a
y
b
e
a f
e t
n
s t
f o
h t
e
n
o
n
v -
l o
t a
e l i
m
e
m
o
y r
e r
a
d
c
r o
e r
c
y l t
d
r u
n i
g
p
o
w
r e
u
. p
w
a
t i
1
0
s
e
c
o
n
d
s
a
n
d
s
w
c t i
h
o
n
a t
t c
h t
e
C
o
m
p
a
n
. y
C
e
l l
C
o
n
s
a t
n
( t
K
)
0
1 .
1
0 .
R
e
s
s i
a t
n
c
e
(
R
)
–
–
1 Ω
M
–
Ω
2
0
0
k
–
Ω
1 Ω
1
0
0
k
M
Ω
Ω
2
0
k
2
0
0
k
Ω
Ω
1
0
k
1
0
0
k
2 Ω
Ω
k
2
0
k
1 Ω
Ω
k
1
0
k
Ω
2 Ω
2
0
0
k
Ω
1 Ω
1
0
0
k
Ω
–
2
0
0
Ω
–
1
0
0
Failure to respond to the input indicates a fault with the
instrument which must be returned to the Company for repair.
Correct response, but with incorrect readings, usually
indicates an electrical calibration problem. Re-calibrate the
instrument as detailed in Section 8.3.
b) If the response in a) is correct, reconnect the conductivity
cell cable and connect the resistance box to the cell end.
Check that the instrument displays the correct values as
set on the resistance box in this configuration.
If the instrument passes check a) but fails check b), check the
cable connections and condition. If the response for both
u
t l
. y
checks is correct, replace the conductivity cell.
h
a
s
*
9.3 Checking the Temperature Input
n
Check that the instrument responds to a temperature input.
Disconnect the PT100 leads and connect a suitable resistance
box directly to the transmitter inputs – see Section 4.3 or 4.4.
Check that the transmitter displays the correct values as set on
the resistance box – see Table 9.3.
Incorrect readings usually indicate an electrical calibration
problem – re-calibrate the instrument as detailed in Section 8.3.
T
e
m
p
e
a r
u t
e r
0
1
0
2
0
2
5
3
0
4
0
5
0
6
0
7
0
8
0
9
0
1
0
0
1
3
0
5 .
Table 9.3 Temperature Readings for Resistance Inputs
°C
n I
p
t u
R
e
s
s i
a t
1
0
0
0 .
0
1
0
3
9 .
0
1
0
7
7 .
9
1
0
9
7 .
3
1
1
1
6 .
7
1
1
5
5 .
4
1
1
9
4 .
0
1
2
3
2 .
4
1
2
7
0 .
7
1
3
0
8 .
9
1
3
4
7 .
0
1
3
8
5 .
0
1
5
0
0 .
0
Ω)
n
c
e
(
25
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