Masoneilan SVI3 Installation and Maintenance Manual
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© 2021 Baker Hughes Company. All rights reserved.
Figure 26 Intrinsically Safe Installation
3.6.5.2 Grounding Practices
To ensure proper grounding make sure that case and ground connections are made in
compliance with the plants normal grounding practices. There must never be more than
one ground point for the shield of the signal wiring. Normally ground is connected at the
controller or at the intrinsic safety barrier
.
The case grounding screws are located on the outside of the case at the lower right of the
cover and inside the cover
.
The case is isolated from all circuitry and can be grounded
locally in accordance with applicable codes.
If noise or instability is present, set the positioner to MANUAL mode of operation and
manually position the valve over its entire range. If the valve is stable in MANUAL mode
then the problem can be noise in the control system. Recheck all wiring connections and
ground points.
3.6.5.3 Compliance Voltage in Single Drop Current Mode
The SVI3 requires 9
.
0 V at 20 mA and 11.0 V at 4 mA. Typical smart devices require
MORE voltage at higher current. The controller supplying the current has LESS voltage
available at higher current. The SVI3 is noteworthy in that it requires LESS Voltage at
higher current that complements the characteristic of the source requiring only
9 V at 20
mA.
See “Split Range Applications” on page 114.
NOTE : Improperly or inadequately grounded installations can cause noise or
instability in the control loop. The internal electronics are isolated from
ground. Grounding the case is unnecessary for functional purposes but
grounding the case may be necessary to conform to local codes.
REMOTE
PV
1-5Vdc
D/I
+ -
4-20mA OUT
+ -
1
SW #2
+ -
SW #1
+ -
2
3
+ -
4-
20
m
A
IN
+
-
REMOTE
PV
1-5Vdc
D/I
+ -
4-20mA OUT
+ -
1
SW #2
+ -
SW #1
+ -
2
3
+ -
4-
20
m
A
IN
+
-
HART
Modem
HART
Modem
HART Compliant
Control System
4-20mA Output
SVI3
Computer
HandHeld
HART
Communicator
Hazardous
Area
Non-Hazardous
Area
+
-
+
-
+
-
Single Channel
Zener Barrier
I.S Galvanic
Isolator
