6
4
CONNECTIONS
Warning.
•
Mains power – before making any connections, ensure that the power supply, any powered control circuits and high
common-mode voltages are switched off.
4.1
Cable, Tubing and Gland Specifications
Information.
•
Five 22mm (0.87 in.) diameter cable entries are provided in the base of the terminal chamber. The cable entries accept
M20 glands (not supplied).
•
External reference air connections are made via
1
/
4
in. compression fittings.
4.2
Electrical Connections
4.2.1
General
Information.
•
Earthing (grounding) – a stud terminal is fitted to the case bus-bar earth (ground) connection – see Fig. 4.2
•
Cable routing – always route signal output cables and mains-carrying/relay cables separately, ideally in earthed metal conduit.
Twist the signal output leads together or use screened cable with the screen connected to the case earth stud.
Use only the cables and air tubing specified in Table 4.1.
Fit suitable cable glands into the entries to be used and blank-off any unused entries using the bungs supplied.
Ensure that the cables enter the instrument through the glands nearest the appropriate screw terminals and are short and
direct. Do not tuck excess cable into the terminal compartment.
•
Relays – the relay contacts are voltage-free and must be connected in series with a power supply and the alarm/control
device which they are to actuate. Ensure that the contact rating is not exceeded.
Refer also to Section 4.2.4 for relay contact protection details when the relays are to be used for switching loads.
•
Retransmission output – Do not exceed the maximum load specification for the selected current retransmission range
(see the associated specification sheet,
SS/ZDT/FG).
The retransmission output is isolated. Therefore the –ve terminal must be connected to earth (ground) if connecting to the
isolated input of another device.
Table 4.1 Cable References and Air Tubing Specification
e
c
n
e
r
e
f
e
R
g
n
i
b
u
T
/
e
l
b
a
C
n
o
i
t
p
i
r
c
s
e
D
e
l
b
a
c
t
u
p
t
u
o
ll
e
C
h
t
a
e
h
s
.
c
.
v
.
p
ll
a
r
e
v
o
h
t
i
w
d
i
a
r
b
r
e
p
p
o
c
n
i
w
t
e
u
l
b
d
n
a
d
e
r
p
u
d
i
a
l
m
m
2
.
0
/
6
1
e
l
b
a
c
e
l
p
u
o
c
o
m
r
e
h
T
2
.
4
e
l
b
a
T
e
e
S
e
l
b
a
c
r
e
t
a
e
H
m
m
1
e
r
o
c
-
3
2
*
)
.
x
a
m
.
t
f
6
6
r
o
m
0
2
(
r
e
p
p
o
c
m
m
5
.
1
e
r
o
c
-
3
2
*
)
.
x
a
m
.
t
f
5
0
1
r
o
m
2
3
(
r
e
p
p
o
c
m
m
2
e
r
o
c
-
3
2
*
)
.
x
a
m
.
t
f
6
2
2
r
o
m
9
6
(
r
e
p
p
o
c
)
r
i
A
e
c
n
e
r
e
f
e
R
(
g
n
i
b
u
T
r
i
A
1
/
4
x
.
d
.
o
.
n
i
1
/
8
e
b
u
t
.
c
.
v
.
p
r
o
n
o
l
y
n
,
l
e
e
t
s
s
s
e
l
n
i
a
t
s
.
d
.
i
.
n
i
t
i
u
d
n
o
c
e
l
b
i
x
e
l
f
g
n
i
d
u
l
c
n
i
,
h
t
g
n
e
l
n
u
r
l
a
t
o
T
*
e
l
p
u
o
c
o
m
r
e
h
T
f
o
e
p
y
T
e
l
b
a
C
g
n
i
t
a
s
n
e
p
m
o
C
h
s
i
t
i
r
B
2
5
9
1
;
3
4
8
1
S
B
n
a
m
r
e
G
4
1
7
3
4
N
I
D
n
a
c
i
r
e
m
A
1
.
6
9
C
M
I
I
S
N
A
+
–
e
s
a
C
+
–
e
s
a
C
+
–
e
s
a
C
(
l
A
-
i
N
/
r
C
-
i
N
K
e
p
y
T
)
n
w
o
r
B
e
u
l
B
d
e
R
d
e
R
n
e
e
r
G
n
e
e
r
G
w
o
ll
e
Y
d
e
R
w
o
ll
e
Y
Caution. The total loop
resistance must be less
than 2
Ω
.
Table 4.2 Thermocouple Wiring
