GE Baker Hughes Masoneilan SVI FF Installation And Operation Manual page 69

Distributed Control Systems Configurations
This section gives guidance for configuration in a DCS application. Figure 36 gives two
generalized drawings that cover DCS applications to ensure switch safety.
+
SVI
Switch
-
+
SVI
Switch
-
Configuration Considerations
A typical value for 24 AWG cable about 0.025 Ohm/ft (see Wiring Option #1)).
If IS barrier is a combination of fuse, resistor and Zener diode then the connection is
shown in Option #2. The barrier must have adequate resistance to limit inrush current,
as the fuse cannot limit inrush current (see Wiring Option #2).
© 2019 Baker Hughes, a GE company, LLC. All rights reserved.
Wiring Option #1
Add resistor so load with
resistance ≥ 30 (including
wire resistance)
Negative switch pole must be directly wired to negative pole of power supply.
Wiring Option #2
Add resistance sized to
limit in-rush current < 50
mA.
Any load. Power source is not directly
connected to the switch.
Load can be a circuit within DCS/PLS
card, between power source and
switch.
Figure 36 DCS Switches Wiring Options
+
Power source can be part of
DCS/PLS card. Power source
requirements: V  30 V. I
max
1 A.
-
+
Power source can be part
of DCS/PLS card. Power
source requirements: V 
-
1 A.
30 V. I
max
Masoneilan SVI FF Instruction Manual
| 69
=