Beckhoff EPP3504-0023 Short Manual page 54

Product overview
The ZB8520 DIN rail fastening is not recommended with regard to the analog protective effect:
• Unless otherwise specified, measurement errors etc. will be stated in electrical DC operation (no use of
AC values). During measurement of an AC value, the frequency slope of the analog input influences
the measurement itself.
Note on temperature
The internal/external temperature of the device affects the measurement through the electronics. A
measuring setup is generally characterized by a temperature dependence, which is specified in the form of a
temperature drift, for example. The specifications apply for a constant ambient temperature. Variable
conditions (e.g. heating of the control cabinet, sudden temperature drop due to opening of the control cabinet
in cold weather) resulting in a temperature change may alter the measured values through dynamic and
heterogeneous temperature distribution. To rectify such effects, the internal temperature of the device can be
read online from the CoE and used for calculation. Some devices also electrically indicate that they have
thermally stabilized; see diagnostic features.
The specification data apply:
• after a warm-up time under operating voltage and in fieldbus mode of least 60 minutes at constant
ambient temperature
◦ practical note: after power-on, the device generally heats up exponentially such that the major
proportion of the heating has occurred within a short period of approximately 10 to 15 minutes,
depending on the device,and the measuring properties shift within the specification limits.
◦ for clarification: typical trend of an internal temperature (no significance for a particular device):
◦ some devices display that they are internally thermally stabilized and ∆T within the device is very
small in the CoE object 0xF900:02 [} 81]. This can be evaluated by an application,
• in horizontal installation position, taking the minimum distances into consideration,
• under natural convection (no forced ventilation),
• provided the specifications are adhered to.
54 Version: 1.2 EPP3504-0023