R7500C Wide Range Proportional
BEFORE INSTALLATION
Temperature Controller
INSTALLATION INSTRUCTIONS
They are fastened to the mounting surface through the two
diagonally opposed mounting holes in the back of the case.
See Fig. 1.
For access to the mounting holes, remove the cover from the
case by loosening the cover mounting screw.
The mounting holes are now visible through the circuit board
notches in the upper right and lower left-hand corners.
Determine placement of the mounting holes in the surface
and scribe the mounting hole locations. Drill pilot holes and
fasten with No. 10 screws.
RC186
Refer to job drawings for specific installation information and
mounting location. Main and compensation sensors (when
used) must be 500-ohm Balco sensors (L7022, L7025,
L7033, T7506 or T7001).
This controller is surface mounted through the two holes in
the back of the case.
Observe ambient temperature (30 to 140F) (0 to 60C) and
relative humidity (5 to 95%) limitations.
No special tools are required to install this controller.
CAUTION:
This controller requires a 11 to 12V dc power supply
for proper operation. The power may be supplied by
an R7503 Modutrol* Motor Converter, R7504 TwoPosition Converter, RP7505 Pneumatic Transducer,
Electronic Modutrol Motors M734K or M745J, any
other device designed for use with this Temperature
Controller, or a separate dc power supply. This
controller outputs 4 to 7 Vdc across the proportional
band setting. It is designed to work with motors and
actuators that expect a 4 to 7 Vdc input signal.
MOUNTING
This controller can be surface mounted in any convenient
location such as on duct walls, end compartments of unit
ventilators, etc.
Fig. 1. Approximate Installation Dimensions in
inches (Millimeters).
Copyright © 1995 Honeywell Inc. • All Rights Reserved
95-7205
R7500C WIDE RANGE PROPORTIONAL TEMPERATURE CONTROLLER
WIRING
All wiring must agree with local electrical codes and
ordinances.
Since the Controller circuits are rated NEC Class 2, some
local codes allow open (no conduit) wiring.
Number 18 gage 1.0 mm insulated wire or two- or threeconductor thermostat cable is acceptable for use with these
Controllers, except on long sensor or remote setpoint
potentiometer runs where a larger wire size should be used.
See T ab le 1.
All control wiring connections to the Controller are made to
the 6-inch (152 mm), color-coded leadwires found bundled
under the cover. There are two orange wires to facilitate
connections to the converter and/or sensors.
Crimp type connectors are recommend for field connections
of the control wiring. Refer to job drawings for specific wiring
information. See Figures 2 through 4 for some typical
wiring diagrams.
IMPORTANT
Observe color-coding of wires when making connections.
BALCO
MAIN SENSOR
1
BLACK
ORANGE
*
ORANGE
YELLOW
VIOLET
R7500
R7503
CONVERTER
*
O
Y
V
POWER
Table 1. Wire Resistance, Ohms per 1,000 Feet (304m).
Wire Gage
Wire Dia.
Size (mm)
Ohms/1000 ft
(304 m) of Wire
18 1.00 6.5
16 1.25 4.0
14 1.60 2.6
12 2.00 1.6
10 2.50 1.0
When determining proper wire size, remember there are two
wires to the sensor and the setpoint potentiometer. Double
the distance to the sensor or potentiometer to obtain the
proper wire length. Calibration of the controller will be
offset approximately 1F (0.5C) for every one ohm of lead
wire resistance.
BALCO MAIN SENSOR
M734K
M745J
14002385-008
REMOTE
SETPOINT
ADJUST
270Ω
3
2
BLK
*
ORN
BRN
R7500
ORN
YEL
VIO
*
O
Y
V
POWER
D
Z
R
1
BROWN
BALCO COMPENSATION
SENSOR
BOTH ORANGE WIRES ARE ELECTICALY IDENTICAL.
*
1
OPTIONAL DISCHARGE COMPENSATION SENSOR.
SUBSTITUTE WITH 500 OHM RESISTOR WHEN
COMPENSATION IS NOT USED.
Fig. 2. Typical Hookup Diagram of R7500C Model with
Integral Setpoint Adjustment.
NOTE: When the compensation sensor is not used,
substitute a 500-ohm resistor and set the
compensation ratio at the maximum setting (20).
95-7205
C7828
BALCO COMPENSATION
SENSOR
CONNECT Z-D FOR DIRECT ACTION; Z-R FOR
1
REVERSE.
2
OPTIONAL DISCHARGE COMPENSATION SENSOR.
SUBSTITUTE WITH 500 OHM RESISTOR WHEN
COMPENSATION IS NOT USED.
MOVE WIPER UP TO RAISE SETPOINT.
3
BOTH ORANGE WIRES ARE ELECTRICALY IDENTICAL.
*
Fig. 3. Typical Hookup Diagram of R7500C with Remote
Temperature Selector.
2
C7829
BALCO
MAIN SENSOR
R7500C WIDE RANGE PROPORTIONAL TEMPERATURE CONTROLLER
11-12 Vdc
+
POWER
–
SUPPLY
MODULTROL IV
MOTOR
1
BLACK
ORANGE
R7500
BROWN
ORANGE
YELLOW
VIOLET
C
R
8.2K
T2
T1
L1
L2
X-FORMER
2
BALCO COMPENSATION
SENSOR
1
C AND T2 ARE INTERNALLY CONNECTED. AN 8.2K OHM RESISTOR IS
PROVIDED INTERNALLY TO CORRECTLY LOAD THE R7500 OUTPUT.
2
OPTIONAL COMPENSATION SENSOR. SUBSTITUTE WITH 500 OHM
RESISTOR WHEN COMPENSATION IS NOT USED.
Fig. 4. Hookup Diagram of R7500 to Modutrol IV Motors.
ADJUSTMENTS & CALIBRATION
ADJUSTMENTS
Set the following adjustments as specified on job drawing or
as required.
TEMPERATURE SETPOINT ADJUSTMENT
Integral setpoint adjustment is provided on the R7500C.
When it is desired to use a remote setepoint adjustment, set
the integral setpoint adjustment knob to the same
temperature as the top end of the remote setpoint scale.
When using the 14002385-008 remote setpoint assembly, set
the integral setpoint knob to REMOTE. Calibration of the
remote potentiometer will then be correct.
M7186A1004
M7185G1000
C7830
PROPORTIONAL BAND (PB) ADJUSTMENT
This adjustment indicates the change in temperature required
at the sensor to move the final control device (i.e., valve,
damper) from one extreme position to the other (full on
to full off). The controller has the highest gain with the lowest
PB setting.
Fig. 5. View of R7500C with Cover Removed Showing
Adjustment Locations.
3
95-7205
R7500C WIDE RANGE PROPORTIONAL TEMPERATURE CONTROLLER
COMPENSATION RATIO ADJUSTMENT
Compensation ratio is the number of degrees temperature
change required at the compensation sensor to change the
primary sensor control point one degree F.
When a compensation sensor (T2) is used, the compensation
ratio adjustment provides a means for adjusting the effect of
the compensation sensor on the primary sensor (T1). For
example, with a compensation ratio setting of 10, a 10
degree F drop in temperature at the compensation sensor is
required to increase the controlled temperature 1 degree F.
This adjustment has a range of 0.25 to 20. A blank table
provided in the controller is for noting the compensation
schedule.
Use the formula below to calculate the compensation ratio for
hot water reset applications:
Comp. Ratio =
Change in outside air temp.
Change in hot water temp. + P.B.
Adding P.B. to the change in hot water temperature
compensates for proportional offset.
CALIBRATION
CHECKOUT AND TESTING
CHECKOUT
The only checkout ordinarily required is to slowly rotate the
Setpoint Adjustment through the total proportional band of the
device to determine if the output devices operate properly.
If the system does not function properly or the controller
appears to be out of calibration, proceed with the following
testing information.
TESTING
Before testing, be sure the Controller power supply (11 to
12 Vdc) is present at test point (+) and (–1) of R7500 models.
If the correct supply voltage is not available at these points,
check the power input device as indicated in the literature
accompanying the applicable unit.
NO. 1 (R1)
CALIBRATION
POTENTIOMETER
POWER SUPPLY
TEST POINT (-)
The R7500 family of controllers are factory calibrated and
checked prior to shipment and should operate satisfactorily
on job startup.
If the sensor and/or the setpoint potentiometer are a long
distance from the controller, it may be necessary to
recalibrate the controller. Calibration potentiometers are
behind the three holes on the left side of the front panel, see
Figure 6. To compensate for main sensor and/or setpoint
potentiometer lead wires or calibration, adjust the middle
potentiometer R7 (Cal. Pot. No. 2) clockwise. This
compensates for leadwire length and a controlling
temperature which is lower than the setpoint. (3.5 degrees
of rotation per ohm of leadwire resistance or per degree
off-calibration).
To compensate for the compensation sensor leadwire
resistance, adjust the top left potentiometer R1 (Cal. Pot.
No. 1) clockwise. (3.2 degrees of rotation per ohm of
leadwire resistance or per degree off-calibration.) Cal. Pot.
No. 1 also can be used to vary the compensation start point
(temperature at which compensation affect is zero). The
factory compensation start point setting is 70F. Turning Cal.
Pot. No. 1 CCW lowers the compensation start point
temperature.
NO. 2 (R7)
CALIBRATION
POTENTIOMETER
POWER SUPPLY
TEST POINT (+)
OUTPUT VOLTAGE
TEST POINT Y1
C8041
Fig. 6. Test Points and Calibration Adjustment Locations.
All R7500 series of controllers include test points on the left
side of the front panel (see Fig. 6). All Controllers have the
following points—
Y1 = Output voltage (yellow leadwire)
–1 = Power supply (–), (violet leadwire)
+ = Power supply (+), (orange leadwire)
Using the appropriate scale voltmeter, insert test probes into
appropriate holes for voltage checks.
95-7205
4
R7500C WIDE RANGE PROPORTIONAL TEMPERATURE CONTROLLER
NOTE:
1. To ensure correct voltage readings in the
following tests, a 500-ohm resistor should be
substituted for the compensation sensor (if its
temperature is not near 75F [24C]) and “comp.
ratio” should be set at 20.
2. If the controller output is not connected, wire a
390 ohm “load” resistor from orange to
yellow wires.
R7500
Adjust setpoint knob to correspond to the ambient
temperature at the main sensor. Set the proportional band
at 5. The output voltage between points Y1 and (+) should be
approximately one-half power supply voltage minus 0.6 Vdc. If
this reading is not found, the device can be recalibrated by
adjusting the calibration potentiometer No. 2 (left center of
panel, see Fig. 6) until this reading is reached.
5
95-7205
Home and Building Control Home and Building Control
Honeywell Inc. Honeywell Limited-Honeywell Limitée
Honeywell Plaza 740 Ellesmere Road
P.O. Box 524 Scarborough, Ontario
Minneapolis, MN 55408-0524 M1P 2V9
Helping You Control Your World
QUALITY IS KEY
95-7205 Rev. 10-95 Printed in U.S.A.
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