Yokogawa 202 Field Mounting Rate Totalizer - Manual (Page 25)

6. INTRINSIC SAFETY
CONNECTIONS
When installing the Model 202A in hazardous areas, the wiring and installation
must comply with appropriate installation standards.
The approval uses entity parameters and an associated apparatus type approval
on the input/output connections to the 4-20mA current loop and alarms. The
4-20mA input and alarm outputs must, therefore, only be connected as shown on
the following page, to barriers with the specified parameters.
The Model 202A will connect directly to a 4-20mA current loop and alarms,
provided they do not exceed the following input parameters:
Ui = 28V
Ii
= 93mA
Pi = 653mW
The internal capacitance seen on the input (terminals 3 & 4) is 0.02uF while the
internal capacitance seen on the output (terminals 5-8) is 0.1uF maximum.
Inductance is negligibly small on both the input and output.
Outputs
The two open collector outputs must only be connected to certified IS equipment
via barriers as shown on the following page. Only certified intrinsically safe
solenoids may be used for IS applications.
Intrinsic Safety Connections 23