Ex i Applications
Some I/O modules are intended to be connected with devices located in hazardous areas. To ensure safety and reliability in these applications, several additional requirements must be considered:
- The node structure meets the additional requirements specified below for the power supply as well as the requirements for air and creepage distances.
- The operator obtains a prototype test certificate that confirms the correct installation of the system and store it in a control cabinet or housing.
Observe the detailed requirements as stated in the original wording of the respective certificate (Installation Regulations Specified by Approvals).
Power Supply Requirements
Only Ex i bus supply modules are permitted to be used for power supply to any node sections containing I/O modules for Ex i applications.
The following Ex i potential supply modules may be used for this purpose: 750-606, 750-625/000-001.
1 | Ex i bus supply module (750-606, 750-625/000-001)* |
2 | Ex i I/O modules |
US | System supply (24 VDC) |
UF1 | Field supply 1 (24 VDC) |
UF2 | Field supply 2 (24 VDC) |
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Clearance and Creepage Distance Requirements
For all sections of a node that contain I/O modules for Ex i use, stricter requirements regarding clearances and creepage distances apply. Before the first such node section, the respective Ex i supply module (750-606 or 750-625/000-001) ensures the required distance.
After each such node section, four distance modules (750-616) must be used. This also applies when the next section also starts with an Ex i supply module (750-606 or 750-625/000-001).
Exceptions:
If the following section consists of an end module for bus extension (750-627), one distance module (750-616) is sufficient.
If the following section consists of one end module (750-600), no distance modules are required.