3) A 4-20mA out-of-normal-range Analog Speed Encoder
Detection feature works as shown in the table below (this is
when
Var01
Encoder_Type_Select is set to 0000):
Speed Sensor’s
Input Current
Range
Message shown
on 4-digit
LED Display
Type of Alarm
3.9mA to
20.7mA
N.A.
(Live Speed)
N.A.
9
(Green zone.)
20.83mA
or higher
CLS
(Closed Circuit)
Yellow_Alarm
8
20.7mA to
20.83mA
HI
(High_mA)
N.A.
8,9
(Green zone.)
1.0mA to
3.9mA
LO
(Low_mA)
Red_Alarm
1.0mA or lower
OPn
(Open Circuit)
Red_Alarm
Note
8
: Because the ‘out-of-range’Analog Speed Encoder HI
and CLS cases have 4-20mA signals exceeding 20.7mA,
these cases are not
Var04
and
Var06
under-speed setpoint
violations (but rather are over-speed cases). Since the ES1
monitors for under-speed and not over-speed, the HI and
CLS cases are not outright speed violations.
However, if an Analog Speed Encoder has its 4-20mA
signal in the CLS range, then most likely the encoder
has been physically damaged. To alert the user to this
possibility the CLS range creates a ‘Yellow_Alarm’ if the
CLS condition exists for more then the
Var05
time delay.
On the other hand, the LO and OPn cases have signals less
than 3.9mA. That means they are under-speed setpoint
violations, and create a ‘Red-Alarm’ if the LO or OPn
conditions exist for more than the
Var07
time delay.
Note
9
: For Analog Speed Encoders, the acceptable signal range
extends up to 20.7mA to allow for display of slight
overspeeds such as 103%, 104%, etc. before ‘HI’ kicks-in.
(This is in contrast to temperature sensor signals having a
maximum acceptable signal of 20.1mA).
A) Concerning the Speed display and ‘out-of-range’ sensor
latching:
The ES1’s ‘out-of-range’ sensor latching feature is slightly
different for the 4-digit Speed display than it is for the
Temperature displays. For the 4-digit Speed display, IF the
Speed Encoder is of the 4-20 mA Analog Encoder type,
AND if it is detected as an ‘out-of-range’ sensor, THEN the
Speed Display will show the appropriate OPn, LO, HI, or
CLS out-of-range sensor message.
However, if the analog Speed Encoder ‘recovers’ on its own
to normal 4-20 mA ranges, then the Speed Display will NOT
‘Latch’ that alpha message, but rather will automatically
return to showing ‘live’ speed in % or in RPM. However,
the Speed’s discrete Yellow and Red LEDs and Speed
Alarm relays do ‘Latch’ once an out-of-range sensor has
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been detected, but the actual Speed display itself does NOT
‘Latch’. This is because for safety reasons, we want to show
‘live’ speeds at all times whenever the speed sensor is within
the normal 4-20 mA range, whether or not the speed sensor
has previously strayed above or below the normal 4-20 mA
range, and then since recovered on its own.
LCD Display and 4-digit LED Speed Display Error
Messages
1) There are hardware error, calibration error, operational error,
and other messages, displayed on the LCD and the 4-digit
LED speed display.
These messages are listed in the following five tables
below, and are listed from highest rank to lowest rank.
(Higher ranking messages can have lower ranking messages
‘silently’ stacked-up behind them, so clearing a higher
ranking message may reveal the next highest ranking error
message behind it - if the prerequisite conditions are met).
The hardware error messages are (these are the highest
ranking):
LCD
Display
Message
LED
Speed
Display
Message
Definition
Err6
Err6
‘Silence_Horn/Alarm_RESET’
command existing for a
continuous 60 seconds or more
Note: If the ‘Silence_Horn/Alarm_RESET’ command
exists for a continuous 60 seconds or more, then it is
assumed that one of the following has occured:
the ‘Silence_Horn/Alarm_RESET’ input at TB33
is ‘shorted-out’,
or the ‘AUX_Silence_Horn/Alarm_RESET’ at
TB31 Pins 9 and 10 are both ‘shorted-out’,
or the Front-Panel’s TEST_LEFT_SIDE and
TEST_RIGHT_SIDE Temperature Rise test
buttons are somehow both ‘shorted-out’.
or the AUX_TEST_LEFT_SIDE and AUX_
TEST_RIGHT_SIDE inputs at TB31 pins 3-4 and
5-6 are both ‘shorted-out’.
If any one of these four events occurs, then a
‘Yellow_Alarm’ or ‘Red_Alarm’’ could happen, but
the ES1 would not be able to latch those alarms and
they would automatically ‘clear’ once their offending
alarm event dissipated. This results in the user never
knowing an ‘Alarm’ came and went, unacknowledged.
This defeats one of the main reasons for using an ES1
in the first place (i.e., latch and hold alarms).
To warn the user of such a ‘short-out’, the Horn-
Relay goes into a 0.25 second ON, 0.25 second OFF,
repeating cycle, the LCD shows ‘Err6’ and the 4-digit
LED Speed Display shows ‘Err6’.
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