An intrinsically safe XL7 can only be connected to a VP550 signal processor unit via a Zener safety barrier. The transducer MUST NOT be connected directly to the signal processor. If your XL7 transducer is not intrinsically safe, please refer to Safe Area installation.
- Mount the transducer in the desired location.
- Connect the transducer to the VP550 through a Zener Barrier located in the Safe Area as shown in Figure 9 and Figure 10.
- An intrinsically safe (I.S.) transducer must always be connected to the VP550 through a suitable Zener barrier, even for testing purposes. The system is NOT intrinsically safe if the barrier is not connected and appropriately earthed.
- Ensure the relevant code of practice is rigorously followed.
- Ensure that the barrier is fitted strictly in accordance with the manufacturer’s instructions. Refer to the most up-to-date version of the relevant manual for the selected barrier type. Manuals are generally available for download from the manufacturer’s website.
- All cable must be certified for intrinsically safe systems (500V rms insulation rated). Recommended cable type: 3-core (each core 0.5 mm² or stranded 16/0.2) with overall screen.
- The maximum cable capacitance should be based on the Open Circuit Voltage (“Voc”) value for the Zener barrier. This is to allow for the possibility that cable voltage will exceed the barrier safety description voltage if the transducer is disconnected while power is applied.
- Ground any spare cable cores and screens to barrier I.S. ground, as shown. The screen and all conductors must be insulated from the external transducer metalwork.
- The XL7 transducer must be powered only by the VP550 processor as shown above. Any deviation from this rule invalidates the warranty and may damage the instrument. If in doubt, please contact Hydramotion before power is applied.
- Terminals numbered 2 and 3 of the Z787 barrier are internally connected to the earth rail mounting and may be used to connect terminal 2 of the XL7 to ground instead of the direct connection to the earth rail as shown in Figure 10.