Mandatory Installation Considerations; Typical Barrier Connection - GasTech D-Guard2 Operator's Manual

9.4.

Mandatory Installation Considerations.

The following information must be adhered to when installing the D-Guard
with this information may give rise to unsafe operation and could render the product invalid against its
certificate.
2
Using the D-Guard Gas Detector in a manner that [i] exceeds its electrical, functional or physical specifications,
or [ii] contrary to its operating restrictions, may create risks to personnel and/or equipment resulting in injury or
death.
2
D-Guard must be powered from an intrinsically safe power source that may be either an intrinsically safe power
supply or UPS or an approved Zener barrier or isolation barrier located in the 'safe-area'.
If using a barrier, the power source does not itself need to be intrinsically safe, but it does need to be located
outside of the hazardous area.
9.4.1

Typical Barrier Connection

Hazardous Area
Connections between D-Guard
When selecting a power source such as an isolation barrier, pay close attention to the terminal entity parameters
for the barrier to ensure that they cannot exceed those of D-Guard
Particular attention should be paid to the maximum voltage output from the barrier (U
not exceed the 28V input voltage limit (U
Similarly, the maximum available power output from the barrier (P
2
input power (P ) of D-Guard
i
Typical suitable barriers are the Pepperl and Fuchs KFD2-STC4-Ex1 or KFD2-STC4-Ex1.H.
A quick check of the data sheet for the KFD2-STC4-Ex1.H barrier shows its U
93mA between connections 1 and 3. All of these parameters safely match D-Guard
Safe Area
2
and other connected equipment must have compatible entity parameters.
2
) of D-Guard .
i
, which is 700mW.
17
2
Toxic Gas Detector. Failure to comply
GasTech Part Number: 57-9010-01
GasTech Part Number: 57-9010-02
2
.
) to ensure that it does
o
) must not exceed the maximum permissible
o
= 27.2V, P = 632mW and I
o o
2
.
2
D-Guard
=
o