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Chapter 5 Programming
5.6.5.8 Span/offset
In order for the Span/offset menu option to be available, the user must turn this feature on in the PROGram,
Measurement, Span&offset menu option (see Section 5.8.2). Once this option has been turned on, the
user can use Span and Offset to compensate for long thermocouple cable runs or thermocouple inaccuracies.
The default value for Span is 1 and the default value for Offset is 0. The Span is a multiplier of the absolute
thermocouple range. The Offset is a value of absolute degrees which is added or subtracted to the
thermocouple reading. Once Span and Offset have been entered, the new adjusted range will be:
New T/C Range = (Full Scale * SPAN) + OFFSET
Note that Span is a multiplier while Offset is an additive.
To adjust the Span and Offset:
Make sure the Span&offset option has been turned on. From the Point Setup menu use the UP (↑ ↑ ↑ ↑ ↑ ) or
DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Span/offset and press the ENTER button. You will be prompted with "ofs →
0.0000←". Use the numeric keys to enter a value for the offset which will be added or subtracted to the
thermocouple value and then press the ENTER button. Note that offset is typically measured around the
ice point which should be 0 °C or 32 °F. The offset would typically be the difference between the thermocouple
reading at this point and the true ice point value. You will then be prompted with "spn → 1.00000←". Use
the numeric keypad to enter the new span value and then press the ENTER button. The span should typically
be measured near the full scale value of the thermocouple using a known temperature or reference. The
span would be the absolute value of the reference divided by the reading of the thermocouple. You will be
returned to the Point Setup menu.
5.6.5.9 Engineering (Eng) units
An Engineering units message with a maximum of five alphanumeric characters may be assigned for
voltage and current inputs to identify the point, e.g. PSI or mA.
To program Engineering units:
From the Point Setup menu use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Eng units and press the
ENTER button. You will be prompted with "units
XXXXX ". Use the alphanumeric keypad to enter up
to five characters for your desired Engineering units and then press the ENTER button to return to the
Point Setup menu.
5.6.5.10 Alarms
A total of five Alarms can be set for each point programmed. These five Alarms can be any combination of
numerous Alarm types (limits). The Alarm deadband (also known as hysteresis) and Alarm delay can also
be programmed for each Alarm set.
To program Alarms:
From the Point Setup menu use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Alarms and press the ENTER
button. The Alarm Setup menu will display up to three choices: Alm limits, Alm deadband, and Alm
delay. Each option is described in the following sections.
Page 5-14
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