diff --git a/tests/measure_multiple_devices.py b/tests/measure_multiple_devices.py
index e2a6001..3fb67a8 100755
--- a/tests/measure_multiple_devices.py
+++ b/tests/measure_multiple_devices.py
@@ -38,6 +38,6 @@ while True:
                 f.write(f'{time():.1f} {CO2} {T_SHT4x} {RH_SHT4x} {T_SCD4x} {RH_SCD4x} {T_SHT4x_signed} {T_SCD4x_signed}\n')
         except minimalmodbus.NoResponseError:
             with open('measure.log', 'a+') as logfile:
-            logfile.write(f'Read error for device {slave_address} at {time()}\n')
+                logfile.write(f'Read error for device {slave_address} at {time()}\n')
             continue
     sleep(10)