Spectrum Controls 1769sc-IF8u - Manual (Page 62)

52 Compact IO ™ Universal Input module
Deter Deter Deter Deter Determining Module mining Module mining Module mining Module mining Module
Update Time Update Time Update Time Update Time Update Time
The module update time is defined as the time required for the module to
sample and convert the input signals of all enabled input channels and
provide the resulting data values to the processor. Module update time can
be calculated by adding the sum of all enabled channel’s times. The
module sequentially samples the enabled channels in a continuous loop.
Channel update time is dependent upon the input filter selection. The
following table shows the channel update times.
Table 4.7 Channel Update
Filter Frequency Channel Update Time
10 Hz
305 ms
50 Hz 66 ms
60 Hz 56 ms
250 Hz 18 ms
500 Hz 12 ms
1 KHz 9 ms
The CJC input is only sampled if one or more channels are enabled for
any thermocouple type. The CJC update time is equal to the largest
channel update time of any of the enabled thermocouple inputs types. In
that case, a single CJC update is done per scan. The cyclic calibration
time only applies when cyclic calibration is enabled and active. If enabled,
the cyclic calibration is staggered over several scan cycles once every five
minutes to limit the overall impact of the module update time.
Effects of Autocalibration on Module Update Time
The module’s autocalibration feature allows it to correct for accuracy
errors caused by temperature drift over the module operating temperature
range (0 to 60°C). Autocalibration occurs automatically on a system mode
change from Program-to-Run for all configured channels or if any
online(1) configuration change is made to a channel. In addition, you can
configure the module to perform autocalibration every 5 minutes during
normal operation, or you can disable this feature using the Enable/ Disable
Cyclic Calibration function (default is enabled). This feature allows you to
implement a calibration cycle anytime, at your command, by enabling and
then disabling this bit.(1)
(1) Not all controllers allow online configuration changes. Refer to your controller’s user manual for details. During an online configuration
change, input data for the affected channel is not updated by the module.