4.101
Date Code 20100129 Instruction Manual SEL-751A Relay
Protection and Logic Functions
Analog Inputs
Table 4.46 summarizes the steps and describes the settings we will carry out in
this example.
NOTE: The AIx0yNAM setting cannot
accept the following and will issue the
Invalid Element message:
Analog Quantities
Duplicate Names
Other AI Names
Because the analog card is in Slot 3, type SET G AI301NAM <Enter> to go
directly to the setting for Slot 3, Input 1. Although the device accepts
alphanumeric characters, the name AIx0yNAM setting must begin with an
alpha character (A through Z) and not a number. The device displays the
following prompt:
AI301 TAG NAME (8 Characters) AI301NAM:= AI301 ?
Use the Instrument Tag Name to give the analog quantity a more descriptive
name. This tag name appears in reports (EVENT, METER, and SUMMARY)
instead of the default name of AI301. SEL
OGIC
control equations, Signal
Profiles, and Fast Message Read use the default names. Use up to eight valid
tag name characters to name the analog quantity. Valid tag names characters
are: 0–9, A–Z, and the underscore (_). For this example, we assign TX_TEMP
as the tag name.
Because this is a 4–20 mA transducer, enter I <Enter> (for current driven
device) at AI301TYP, the next prompt (enter V if this is a voltage-driven
device). The next two settings define the lower level (AI301L) and the upper
level (AI301H) of the transducer. In this example, the low level is 4 mA and
the high level is 20 mA.
AI301 TYPE (I,V) AI301TYP:= I ?
NOTE: Because the SEL-751A
accepts current values ranging from
–20.48 to 20.48 mA, be sure to enter
the correct range values.
The next three settings define the applicable engineering unit (AI301EU), the
lower level in engineering units (AI301EL) and the upper level in engineering
units (AI301EH). Engineering units refer to actual measured quantities, i.e.,
temperature, pressure, etc. Use the 16 available characters to assign
descriptive names for engineering units. Because we measure temperature in
Ta b le 4 . 4 6 S um m a r y o f S t e p s
Step Activity Te rse D es c ri pt i on
General
1 SET G
AI301NAM
Access settings for INPUT 1
2 TX_TEMP Enter a Tag name
3 I Select type of analog input; “I” for current
Transducer
High/Low
Output
4 4 Enter transducer low output (LOW IN VAL)
5 20 Enter transducer high output (HI IN VAL)
Level
6 Degrees C Enter Engineering unit
7 –50 Enter Engineering unit value LOW
8 150 Enter Engineering unit value HIGH
Low Warning/
Alarm
9 OFF Enter LOW WARNING 1 value
10 OFF Enter LOW WARNING 2 value
11 OFF Enter LOW ALARM value
High Warning/
Alarm
12 65 Enter HIGH WARNING 1 value
13 95 Enter HIGH WARNING 2 value
14 105 Enter HIGH ALARM value
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