Publication 1769-UM005A-EN-P
Module Data, Status, and Channel Configuration
4-29
EXAMPLE
Two Channels Enabled Using the Same Input Class with Cyclic Calibration Enabled
Channel 0 Input: 100
Ω
Platinum 385, 1.0 mA source (Class 2) with 60 Hz Filter
Channel 1 Input: 1000
Ω
resistance, 0.5 mA source (Class 2) with 60 Hz Filter
From Table 4.15, Channel Update Time vs. Filter Frequency, on page 4-26:
1. Calculate Module Update Time
without
an Autocalibration Cycle
= Ch 0 Update Time + Ch 1 Update Time = 53 ms + 53 ms = 106 ms
2. Calculate Module Update Time
during
an Autocalibration Cycle
Channel 0 Step 1 (Module Scan 1)
= Ch 0 Update Time + Ch 1 Update Time
+ Ch 0 Offset Time
= 53 ms + 53 ms +
73
ms = 179 ms
Channel 0 Step 2 (Module Scan 2)
= Ch 0 Update Time + Ch 1 Update Time +
Ch 0 Gain Time
= 53 ms + 53 ms +
106
ms = 212 ms
Channel 0, Step 3 (Module Scan 3)
= Ch 0 Update Time + Ch 1 Update Time +
Ch 0 Gain Time
= 53 ms + 53 ms +
73
ms = 179 ms
Channel 0, Step 4 (Module Scan 4)
= Ch 0 Update Time + Ch 1 Update Time +
Ch 0 Gain Time
= 53 ms + 53 ms +
73
ms = 179 ms
Channel 0 Step 5 (Module Scan 5)
= Ch 0 Update Time + Ch 1 Update Time +
Ch 0 Gain Time
= 53 ms + 53 ms +
106
ms = 212 ms
Channel 0 Step 6 (Module Scan 6)
= Ch 0 Update Time + Ch 1 Update Time +
Ch 0 Gain Time
= 53 ms + 53 ms +
73
ms = 179 ms
The above 6-step cycle could potentially take place for channel 1 as well. However, since channel
1 is the same input class as channel 0, it uses the same calibration factors as channel 0, and no
additional time is required. At this point, the current source calibration cycle is run.
Current Source (Module Scan 7)
= Ch 0 Update Time + Ch 1 Update Time +
Current Source Offset Time
= 53 ms + 53 ms +
73
ms = 179 ms
Current Source (Module Scan 8)
= Ch 0 Update Time + Ch 1 Update Time +
Current Source Offset Time
= 53 ms + 53 ms +
106
ms = 212 ms
Current Source (Module Scan 9)
= Ch 0 Update Time + Ch 1 Update Time +
Current Source Resistor Time
= 53 ms + 53 ms +
303
ms = 409 ms
3. Calculate Total Time to Complete Autocalibration Cycle
= (Channel Step Times) + (Current Source Times)
= (179 ms + 212 ms + 179 ms + 179 ms + 212 ms + 179 ms) + (179 ms + 212 ms + 409 ms)
= 1140 ms + 800 ms = 1940 ms = 1.940 seconds
After the above cycles are complete, the module returns to scans without autocalibration for
approximately 5 minutes. At that time, the autocalibration cycle repeats.
If both cyclic autocalibration and lead wire compensation (see page 4-30) are enabled, the two
functions run concurrent to one another.
Summary of Contents for Compact 1769-IR6
Page 1: ...Compact I O RTD resistance Input Module Catalog Number 1769 IR6 User Manual AB PLCs ...
Page 10: ...Publication 1769 UM005A EN P P 4 ...
Page 40: ...Publication 1769 UM005A EN P 3 16 Installation and Wiring ...
Page 74: ...Publication 1769 UM005A EN P 4 34 Module Data Status and Channel Configuration ...
Page 115: ...AB PLCs ...
