Open Circuit Mode [Words 1 - 8 (Bits 12 & 13)]; Disable Cjc [Words 1 - 8 (Bit 14)]; Temperature Units [Words 1 - 8 (Bit 15)]; Low Alarm Threshold [Words 9,12,15,18,21,24,27,30] - Spectrum Controls 1794sc-IRT8I User Manual

3-12 Flex™ IO Isolated RTD/Thermocouple Module
User's Manual Pub. 0300242‐01 Rev. A
3.4.5 Open Circuit Mode [Words 1 – 8 (Bits 12 & 13)]
The open circuit mode determines the fail-safe data value each channel is to default to in
the event of an open circuit condition. The table below lists the available options.
Table 3-7 (Open Circuit Mode)
Bit 13 Bit 12 Open Circuit Mode:
0 0 Zero analog value on broken input.
0 1 Set analog value to Max scale on broken input.
1 0 Set analog value to Min scale on broken input.
1 1 Previous Value
3.4.6 Disable CJC [Words 1 – 8 (Bit 14)]
This bit is used to disable CJC compensation for the associated channel.
Table 3-8 (Disable CJC)
State Function
1
0 CJCs Enabled
1
1 CJCs Disabled
1
This field is only used if the input type is a thermocouple and the
format is not a CJC format. No compensation is performed on the
thermocouple when disabled.
3.4.7 Temperature Units [Words 1 – 8 (Bit 15)]
This bit enables Celsius or Fahrenheit for the associated channel.
Note: If the associated channel is not configured for an RTD or
thermocouple, the temperature units have no effect.
Table 3-9 (Temperature Units)
State Function
0 Degrees C
1 Degrees F

3.4.8 Low Alarm Threshold [Words 9,12,15,18,21,24,27,30]

Low alarm threshold setting for channels 0 through 7, respectively.
Note: The data range is determined by the data format selected.

3.4.9 High Alarm Threshold [Words 10,13,16,19,22,25,28,31]

High alarm threshold setting for channels 0 through 7, respectively.
Note: The data range is determined by the data format selected.

3.4.10 User Alarm Deadband [Words 11,14,17,20,23,26,29,32]

The deadband is a range through which the measured input may be varied without
initiating and alarm response. The deadband setting must adhere to the following rules:
•
The deadband must be greater or equal to zero.
•
The deadband cannot exceed 25% of full scale.
•
The alarm limits including deadband may not exceed the user range limits.
•
The low alarm including deadband may not overlap the high alarm including