- Power Requirements :
i. Elixir Namur : Input Voltage is 13V Max.
Input Current 16mA Max.
Input Power 65mW Max.
ii. Coat Endure Namur : same as above
we need also input inductance and capacitance
For Elixir Namur : input inductance and capacitance is Zero
For Coat Endure : Input Inductance is 22uH and Input Capacitance is Zero
- Introduction :
a. Component Selection : like Capacitor Inductor fuse etc.
i. Total capacitance value is depends on Maximum voltage of product
Note : see table A.2 of standard IEC60079-11
and if it is not possible to minimize capacitor value according to table A.2 then we can use encapsulation to hide input capacitance
ii. Fuse selection
Note : see clause 7.3 of standard IEC60079-11
iii. Inductor selection see clasue 8.3.2 of standard IEC60079-11
if we use certified barrier supply to provide input supply for our circuit then the maximum output value of inductor of barrier supply will be the input inductor value for our circuit
b. PCB Design : we need to maintain clearance and creepage distance in pcb according to maximum input voltage
Note : see table 5 of standard IEC60079-11
c. Safety Circuits : For safety of our product we can add zener barrier in our product circuit. We can use Zener barrier circuit as a protection circuit or safety circuit for our product see Figure 1 A zener barrier circuit is a simple circuit where voltage is limit by a zener diode and current is limited by a resistor and also use fuse to protect zener diode.
Note : 1. Fuse is not compulsory for every circuit it is not a safety components for our product
Diode Selection : Selection of zener diode package, power and voltage according to input supply of circuit
Example : If max supply voltage is 10V we can select zener diode voltage is 9.1V and its power is also depend on max. Current
If we apply for certification of
Ex ia : use three zener diode in parallel
Ex ib : use two zener diode in parallel
Ex ic : use one zener diode in parallel
Figure 1
d. Power Supply : Use low power, low quiescent current DC-DC converter for supply
- Process Aspects/Testing Procedure for Production : we need to submit documents
a. SCH and PCB layout drawing file
b. BOM in excel sheet
c. safety components (like diode resistor etc.) and IC, piezo, connector, other special components data sheet
d. Encapsulation process document if we can use
i. We need to explain what type of epoxy we can use for encapsulation
ii. how to apply it and what components will cover when it apply
iii. what time is required for dry epoxy
iv. what time required to be set epoxy and what should be temperature
e. Practical experiments documents
i. Practical Challenge Encountered in Temperature Testing :
How to maintain ambient temperature at different different process temperature
How to maintain electronic temperature with different range of process temperature
Testing with different range of process temperature and plot graph with respect of ambient temperature
According to maximum range of process temperature we can select temperature class for certificate
Example : If maximum process temperature is 200°C then we can apply for T3,T4,T5,T6 class of certificate
ii. Temperature Testing Documents : we can need to proper temperature testing documents including ambient temperature and process temperature range
Example : All reading in °C in table
| Time | Process Temp | Ambient Temp. | PCB Housing enclosure Base | electronics |
| 10:00 | 100 | 33.5 | 45.5 | 36.5 |
| 11:00 | 100 | 33.9 | 45.8 | 36.4 |
| 12:00 | 100 | 33.1 | 45.6 | 36.4 |
iii. Insulation Resistance and Experiments : use megger meter to this testing. it is high voltage testing between input terminal and earth terminal for 500V r.m.s for 60 seconds.
f. Manual Update : Update manual according to certification
i. Add input supply parameters as used in certificate (like Input power consumption, max. Voltage and current, Input capacitance and input inductance etc.)
ii. Add process temperature and ambient temperature range with graph
iii. Add certification code
iv. Add installation guideline (How to install it)