Spectrum Controls 1769sc-IF8u - Manual (Page 65)

Chapter 4: Module Data, Status, and Configuration 55
Impact of Autocalibration on Module Startup During Mode Change
Regardless of the selection of the Enable/Disable Cyclic Calibration
function, an autocalibration cycle occurs automatically on a mode change
from Program-to-Run and on subsequent module startups/initialization for
all configured channels. During module startup, input data is not updated
by the module and the General Status bits (S0 to S7) are set to 1,
indicating a Data Not Valid condition. The amount of time it takes the
module to startup is dependent on channel filter frequency selections as
indicated in Table 4.7, Channel Update Time. The following is an example
calculation of module startup time.
EXAMPLE 1.Two Channels Enabled for Different Inputs
Channel 0 Input: Type T Thermocouple with 60 Hz filter
Channel 1 Input: Type J Thermocouple with 60 Hz filter
Module Startup Time
= (Ch 0 Gain Time + Ch 0 Offset Time) + (Ch 1 Gain Time + Ch 1 Offset
Time)
+ (CJC Gain Time + CJC Offset Time) + (CJC Data Acquisition + Ch 0
Data Acquisition + Ch 1 Data Acquisition)
= (101 ms + 73 ms) + (101 ms + 73 ms) + (101 ms + 73 ms) + (56 ms +
56 ms + 56 ms)
= 174 ms + 174 ms + 174 ms + 168 ms = 690 ms