Bulletin No. APLCL-G
Drawing No. LP0129
Released 3/05
Tel +1 (717) 767-6511
Fax +1 (717) 764-0839
www.redlion.net
MODEL APLCL - APOLLO CURRENT-LOOP INDICATOR
!
DUAL RANGE, 4 to 20 mA or 10 to 50 mA
*
!
3 1/2-DIGIT, 0.56" (14.2 mm) HIGH LED READOUT
!
SEALED METAL FRONT BEZEL (NEMA 4/IP65)
!
24 VDC EXCITATION SUPPLY (Optional)
!
WIDE RANGE SPAN & OFFSET SCALING
!
FRONT ACCESS TO CALIBRATION TRIM CONTROLS
!
OVER-RANGE INDICATION
!
PLUG-IN TERMINAL STRIPS
!
SELECTABLE DECIMAL POINTS
*
Also adapts to 0 to 50, 0 to 20, 0 to 10, 1 to 5 mA ranges as well as
bi-polar inputs.
DESCRIPTION
The premium features of the Apollo Series can now be applied to
measurement of process variables. With its high sensitivity and
programmability, the Apollo Current-Loop Indicator (APLCL) can be set up for
a wide variety of applications. In most plants the APLCL can be used for 90 to
95% of current-loop indicator needs for readout of pressure, flow, temperature,
level and other variables.
The rugged construction and sealed metal front bezel meet the requirements
of NEMA 4/IP65, when properly installed. This allows the APLCL to be used
in dirty, hostile environments and in wash-down areas. In addition, the attractive
flat-black and brushed aluminum front dresses up any control panel.
SAFETY SUMMARY
All safety related regulations, local codes and instructions that appear in the
manual or on equipment must be observed to ensure personal safety and to
prevent damage to either the instrument or equipment connected to it. If
equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.
SPECIFICATIONS
1.
DISPLAY:
3 1/2-digit (1999), 0.56" (14.2 mm) L.E.D., minus sign displayed
on negative current flow. Decimal points inserted before 1st, 2nd, or 3rd least
significant digits by DIP programming switches.
2.
POWER:
Available for 115 or 230 VAC ±10%, 50/60 Hz, 6 VA.
3.
INPUT SENSITIVITY:
(Numerical Readout Change/mA)
260 units/mA @ 4 to 20 mA input
105 units/mA @ 10 to 50 mA input
(max. allowable input current, 170 mA)
4.
COMPLIANCE:
Voltage drop across input at max. signal current, less than
600 mV for both 4 to 20 and 10 to 50 mA ranges.
5.
INPUT RESISTANCE:
4 to 20 mA
- 29.2
Ω
10 to 50 mA
- 11.8
Ω
6.
SCALING RANGE:
SPAN:
32 coarse steps
(binary progression with 5 DIP switches, rear
access).
Each step providing approx. 8.125 numerical units/mA/step
sensitivity for 4 to 20 mA input and 3.25 units/mA/step for 10 to 50 mA
input. Fine adjust
(front access)
brackets the coarse step increments.
OFFSET:
16 coarse steps
(binary progression with 4 DIP switches, rear
access)
with ± switch to add or subtract offset. Each step adds or subtracts
approximately 175 from the numerical display for a total offset range of
±2700. Front access fine control brackets the steps.
7.
LINEARITY:
±(0.05% ±1 digit)
8.
READING RATE:
2 1/2 updated readings/second, nominal.
9.
RESPONSE TIME:
1 second to settle for step change.
10.
NORMAL MODE REJECTION:
63 dB, 50/60 Hz.
11.
COMMON MODE REJECTION:
100 dB, DC to 50/60 Hz.
12.
ENVIRONMENTAL CONDITIONS:
Operating Range:
0° to 60°C
Storage Temperature:
-40° to 80°C
Operating and Storage Humidity:
85% max. relative humidity (non-
condensing) from 0°C to 50°C.
Span Temperature Coeff.:
100 PPM/°C
Offset Temperature Coeff:
100 PPM/°C
Altitude:
Up to 2000 meters
13.
EXCITATION SUPPLY (Optional):
24 VDC @ 60 mA max. Regulated
and isolated
(floating).
(See Ordering Information.)
14.
CONSTRUCTION:
Die cast metal front bezel with black, high impact
plastic insert. Front panel meets NEMA 4/IP65 requirements for indoor use
when properly installed. (Panel gasket and mounting clips included.)
Installation Category II, Pollution Degree 2
15.
CONNECTIONS:
Plug-in, compression type barrier terminal strip.
16.
WEIGHT:
1.2 lbs (0.54 Kg).
CAUTION:
Read complete instructions prior to
installation and operation of the unit.
CAUTION:
Risk of electric shock.
DIMENSIONS In inches (mm)
Note: Recommended minimum clearance (behind the panel) for
mounting clip installation is 2.1" (53.4) H x 5.5" (140) W.
PANEL CUT-OUT
1
SIMPLIFIED SCHEMATIC, APOLLO CURRENT-LOOP INDICATOR
DESCRIPTION OF OPERATION
The Apollo Current-Loop Indicator
(APLCL)
consists of a digital voltmeter
combined with an analog scaling circuit(shown
above).
The unit was designed
primarily for use with 4-20 mA and 10-50 mA current-loop signal circuits.
However, it can also be adapted to other current ranges, such as 0-50 mA, 0-20
mA, 0-10 mA, and in a great many applications it can be used even with 0-5 mA
and 1-5 mA current loops. In addition, input current can be reversed in polarity
resulting in negative numerical readout with a minus
(-)
sign displayed.
Input terminals 3 and 4 are connected in series with 10-50 mA current-loops,
and Terminal 3 and 5 are series connected with 4-20 mA loops. In either case,
the voltage drop “V
I
” generated across the shunt resistor(s) ranges from
approximately 0.12 V min.
(@ 4 or 10 mA)
to 0.59 V max.
(@ 20 or 50 mA).
The buffer amplifier
(K1)
conditions and filters the input signal voltage and
applies it to the input of the scaling circuit.
The procedure for scaling Apollo Current-Loop Indicators is simplified by
dividing the scaling process into two separate components, span adjustments
and offset adjustments which are defined in the following discussion.
The approximate span contributed by each switch is shown on the rear label.
These values are based on the standard current-loop spans of 4 to 20 mA
(16 mA
current variation)
and 10-50 mA
(40 mA current variation).
In other words, if S7
only is turned
“ON”,
the numerical readout will display a change approximately
1050 for a current swing of 16 mA
(4-20 mA input)
or 40 mA
(10-50 mA input).
If S8 were also turned
“ON”,
the numerical readout would swing approximately
1575
(1050 for S7 + 525 for S8)
for the same signal current variation. The fine
control has a continuous span range of approximately 0-150.
OFFSET ADJUSTMENTS
In the foregoing discussion of span, the transfer curves were shown as
“ZERO-BASED”,
i.e., the numerical readout displays
“0”
when the signal
current goes to zero. With current-loop ranges such as 0-5 or 0-10, or 0-20 mA,
and with Bi-Polar
(+/-)
signals, this is often the desired condition. However,
with 4-20 and 10-50 mA current-loops, the minimum current level of 4 or 10
mA usually represents the zero level of the parameter being displayed. There are
also many applications where the minimum
(or zero level)
represents some
value that does not fall on a zero based transfer curve.
To accommodate non-zero based applications, the Apollo Current-Loop
Indicator has provisions for offsetting the transfer curve over a wide range.
Essentially, offset moves the transfer curve up or down to change its intercept
with the numerical readout axis, but it does not change the slope
(SPAN)
of the
transfer curve.
In the Apollo Current-Loop Indicator, offset is accomplished by adding
(or
subtracting)
a constant at the input of the summing amplifier
(K2).
This offset
constant is summed in with a switched binary resistor network and a fine adjust
offset control in a similar manner to that used for span adjustment. Switches S2-
S5
(at the rear)
can be turned on in combinations to give 16 different coarse
offset levels.
Each switch is labeled to show the
approximate amount of offset contributed
when it is turned
“ON”.
Switch 1 selects
the polarity of the switched-in offset value
and allows offsetting the transfer curve
“UP” (adding the offset constant)
or
“DOWN” (subtracting).
The fine control
(front panel, right)
has a numerical readout
range of ±100 and brackets all the coarse
switched ranges.
SPAN ADJUSTMENTS
Span is defined as the numerical range that the display traverses, disregarding
decimal points, when the input signal current is varied from minimum
(4 or 10
mA)
to maximum
(20 or 50 mA).
For example, if a unit is to display 25.0 @ 4 mA and 100.0 @ 20 mA, the
span is 750
(the difference between 250 and 1000).
Had the minimum display
been -25.0 @ 4 mA and +100.0 @ 20 mA, the span would be 1250 (1000 - (-
250) = 1250).
(Note: the terms “GAIN”, “SCALE”, and “SENSITIVITY” are
also frequently used interchangeably with the term “SPAN”.)
The Apollo Current-Loop Indicator can be set up over a very wide span range
by means of the coarse DIP switches S6-S10
(on the rear),
and the fine
screwdriver adjustment pot, located behind the sealing screw on the front bezel
(left side).
The coarse span switches add parallel input resistors to the summing
amplifier
(K2),
thereby increasing its gain, or sensitivity, as more summing
resistors are added.
Effectively, adding more parallel input
resistors, increases the slope of the transfer
curve
(at right)
and increases the numerical
readout for a given input signal current
change. The input summing resistor values are
weighted in a binary progression, so they can
be switched in combinations to give 32
discrete steps of span. The front panel fine
adjust control brackets these coarse steps and
can be adjusted to the exact span needed.
2
CALIBRATION
Direct calibration in the signal loop is usually not practical due to the
difficulty in varying the measured parameter and the confusing interaction that
occurs between span and offset adjustments. However, the APLCL can be
quickly and easily bench calibrated using a commercially available current
calibrator or the calibration set-up shown below.
APPLICATION EXAMPLES
Example 1:
An APLCL is to be calibrated to match a flow transducer whose
output is 10 mA @ 0 GPM and 50 mA @ 1375 GPM.
READOUT SPAN (RS) = 1375
−
0 = 1375
SWING CURRENT (IS) = 50 mA
−
10 mA = 40 mA
ADJUSTMENTS (Refer to the transfer curve below)
A Null the unit to zero readout @ 0 current per Steps 1, 2, and 3 of the
calibration procedure.
B Set the coarse and fine span adjustments to get a readout of 1375 @ 40
mA per Steps 4 and 5.
Note: With the full standard swing of 40 mA, the
coarse span switch reference markings can be used to determine
settings as follows:
S7 ON (1050) + S9 ON (260) = 1310 Span set with switches.
375 (needed) - 1310 (with SW’s) = 65 w. fine span adj.
CALIBRATION PROCEDURE
The procedure outlined below, minimizes span/offset interaction and
simplifies calibration. In Steps 1, 2 and 3 the unit is
“nulled”
to zero readout
with zero input signal current. In Steps 4 and 5, the span adjustments are made
to establish the required slope of the transfer curve.Then in Step 6, the transfer
curve is shifted up or down as required by setting the offset adjustments. In Step
7, the final
“tweaking”
adjustments are made at minimum and maximum signal
current. Setting the decimal points in Step 8 completes the calibration.
Before calibrating, the READOUT SPAN (R
S
), SWING CURRENT (I
S
)
must be determined.
R
S
=
(Max. Numerical Display)
-
(Min. Numerical Display)
(Disregard Decimal Points)
I
S
=
(Current @ Max. Display)
-
(Current @ Min. Display)
Example:
Readout is to be 5.00 @ 4 mA and 15.00 @ 20 mA.
READOUT SPAN (R
S
) = 1500
−
500 = 1000
SWING CURRENT (I
S
) = 20 mA
−
4 mA = 16 mA
C Set offset to readout 0 @ 10 mA per
Step 6.
Note: The readout observed
when the 10 mA min. current is first
applied can be used to determine the
offset switch settings.)
In this
example the readout will be
(+)
344
when the 10 mA min. current is first
applied. Applying -344 offset then
reduces the readout to zero @ 10 mA.
D Check readout at max.
(50 mA)
and
min.
(10 mA)
and fine tune
(tweak)
as required per Step 7.
Example 2 (Negative Slope):
A level measuring device puts out 6 mA when
a storage tank is full and 15 mA when the tank is empty. The APLCL is to
readout 90.0 tons at full tank and zero when empty.
READOUT SPAN (RS) = 900
−
0 = 900 (Disregard Decimal Points)
SWING CURRENT (IS) = 6 mA (@ max rdg) - 15 mA (@ min rdg) = -9 mA
In this case, the signal current is reverse [Term 3
(-)
with respect to Term
5
(+)]
causing the readout to go
“down” (increasingly negative)
as the
negative current increases.
ADJUSTMENTS
A Null the unit per Steps 1, 2 and 3.
B Set slope of transfer curve with span
adjustments to get readout of -900 @
-9 mA per Steps 4 and 5.
C Move transfer curve up by applying
(+)
offset per Step 6 until readout is
+900 @ -6 mA.
D Check extreme readings per Step 7,
0 readout @ -15 mA and +900
readout @ -6 mA.
Set D.P. Switch S1 and replace front
panel sealing screws.
Example 3 (± Display):
A differential pressure transducer has a range of
±1500 PSI with a 4 to 20 mA output
(-1500 @ 4 mA, +1500 @ 20 mA).
READOUT SPAN (RS) = +1500
−(−1500)
= 3000
SWING CURRENT (IS) = 20 mA(max) - 4 mA(min) = 16 mA
ADJUSTMENTS
1. Turn off all coarse offset and span adjustment switches
(S2-S10 down).
S1 has no effect when zeroing and can be in either position.
2. Apply zero current by opening the external zero current switch. Adjust
the indicator to read zero using the fine offset adjustment
(R.H. side,
front panel).
3. Close the external zero current switch and set the SWING CURRENT,
I
S
,
(16 mA in the example)
by adjusting the power supply voltage and
the external fine adjust pot. Then, turn the fine span control
(front, left)
to get a near zero reading
(Adjustment fully CCW)
4. With the SWING CURRENT I
S
, applied to the input, set up a
combination of coarse span adj. switches
(S6-S10)
to obtain a display
readout closest to the READOUT SPAN desired
(1000 in the example).
Set the exact READOUT SPAN with the fine span adj.
(front, left).
5. Repeat Step 2 to see if the zero value has shifted. If it has, re-zero with
fine offset
(front, right),
then repeat Step 3 and 4.
6. After the span has been adjusted, set the signal current to the minimum
level
(4 mA in example).
Then set the offset add/subtract switch
(S1),
the coarse offset switches
(S2-S5)
and the fine offset control
(front,
right)
to obtain the readout corresponding to this minimum current
value
(500 in the example).
7. Adjust the input signal current to its maximum value to see if the proper
readout is obtained
(1500 @ 20 mA in the example).
If the readout is
slightly off, adjust the fine span
(front, left)
to obtain the true reading.
Then, recheck the reading at minimum input current
(4 mA)
and
readjust fine offset
(front, right)
if necessary. Repeat the maximum and
minimum readout adjustments until the unit displays the proper readout
at both extremes.
8. Set decimal points as desired using the three switches on the side of the
case and replace the front panel sealing screws. The unit can now be
installed.
SETTING ZERO
OFFSET
Note: Since the display readout is limited to 1999 numerical indication,
the full READOUT SPAN of 3000
cannot be obtained during zero
based span adjustment. However,
dividing both the READOUT SPAN
and SWING CURRENT by two, i.e.
1500 readout @ 8 mA, allows the
span adjustment to be made for the
proper transfer curve slope.
ADJUSTMENTS
A Null the unit per Steps 1, 2, and 3.
B Set transfer curve slope with span
adjustments per Steps 4 and 5, to get
a readout of +1500 @ 8 mA.
C Apply
(-)
offset per Step 6 to get a
reading of -1500 @ 4 mA.
D Check min. and max. extremes and
tweak if required to get desired
readout @ 4 and 20 mA per Step 7.
MAX/MIN CHK.
SPAN
3
CONNECTIONS
2-WIRE, WITHOUT EXCITATION
2-WIRE, WITH EXCITATION (Series Conn.)
3-WIRE, WITH EXCITATION (Parallel Conn.)
NOTES:
1. When shielded wire leads are used, connect the shield to Terminal 3 at the
indicator and insulate the other end to avoid contact with machine ground.
2. Never run signal leads in conduit, bundles, or race ways with power
conductors. Avoid runs close to contactors, relays, solenoids, transformers,
and other potential sources of electrical noise.
INSTALLATION ENVIRONMENT
The unit should be installed in a location that does not exceed the maximum
operating temperature and provides good air circulation. Placing the unit near
devices that generate excessive heat should be avoided.
The bezel should be cleaned only with a soft cloth and neutral soap product.
Do NOT use solvents.
Continuous exposure to direct sunlight may accelerate the aging process of
the bezel.
Installation
The Apollo Current-Loop Indicator is designed to be panel-mounted into an
enclosed panel with a gasket to provide a water-tight seal. Two mounting clips
and screws are provided for easy installation. Consideration should be given to
the thickness of the panel. A panel which is too thin may distort and not provide
a water-tight seal. The APLCL meets NEMA 4/IP65 requirements for indoor
use when properly installed. (Recommended minimum panel thickness is 1/8".)
Cut the panel opening to the specified dimensions. Remove burrs and clean
around the panel opening. Slide the panel gasket over the rear of the unit to
the back of the bezel. Insert the unit into the panel. As depicted in the drawing,
install the screws into the narrow end of the mounting clips. Thread the screws
into the clips until the pointed end just
protrudes through the other side.
Install each of the mounting clips by
inserting the wide lip of the clips into
the wide end of the hole, located on
either side of the case. Then snap the
clip onto the case. Tighten the screws
evenly to apply uniform compression,
thus providing a water-tight seal.
Caution:
Only minimum pressure is
required to seal panel. Do
NOT
overtighten screws.
TROUBLESHOOTING
For further technical assistance, contact technical support at the appropriate company numbers listed.
ORDERING INFORMATION
MODEL NO.
DESCRIPTION
PART NUMBERS FOR AVAILABLE
SUPPLY VOLTAGES
230 VAC
115 VAC
**APLCL
Apollo Current-Loop Indicator w/o Excitation
Apollo Current-Loop Indicator w/24 VDC Excitation Supply
APLCL410
APLCL411
APLCL400
APLCL401
For information on Pricing, Enclosures, & Panel Mount Kits refer to the RLC Catalog or contact your local RLC distributor.
**
Units are shipped calibrated to read 000.0 to 100.0 with 4 to 20 mA input.
