Property, plant and equipment (PPE) is considered as a non-monetary asset on your balance sheet. In case you acquired it with foreign currency, it’s treated as any other non-monetary asset intially accounted in foreign currency at the balance sheet date.
On the date of the acquisiton, the value in foreign currency is translated into the value of your functional currency, i.e. the currency you use in your daily accounting. Say you bought a machine with the value of USD 10,000 and your functional currency is actually EUR. For simplicity lets presume that the exchange rate at the date of the purchase for USD was 0.7 EUR. That is for 1 USD you would get 0.7 EUR. The value of the machine in your accounting would thus be 10,000 x 0.7 = 7,000 EUR. Subsequently you’d treat the asset as you would do with any other, you depreciate it over its useful life.
Now comes a balance sheet date however and the rate for USD / EUR has changed to 0.8. Should you change the cost of the asset? The answer is “no” since as we mentioned earlier, PPE items are non-monetary and as such, their cost remains the same as it was at the date of the acquisition itself.