Honeywell R7426A SPECIFICATION DATA

MicroniK 200

Fig. 1. Temperature controller

R7426A

TEMPERATURE CONTROLLER

WITH REAL-TIME CLOCK

SPECIFICATION DATA

GENERAL

The R7426A temperature controller covers all space, air or
water flow temperature applications within the selectable
control range of 0...50°C (LOw range) or 0...130°C (HI range)
with optional high or low limit control and outside air
temperature compensation reset of the main setpoint. The
controller can be configured to perform space-discharge air
or supply water temperature cascade control.

FEATURES

 Weekly time schedule with up to six switching points

per day

 Automatic daylight saving time change

 Four different operating modes: Comfort, Standby,

Night, and OFF

 Yearly holiday programming in advance

 Three types of holiday schedules

 Self-adaptive optimum start program for room control

system

 Night cycle program

Fig. 2. LC Display

Order Numbers

Order-No. Controller Description

R7426A2014 Temperature controller with integrated

real-time clock (RTC), Plant/System
ON/OFF output, and one 3-position
floating output. The controller offers the
choice of selectable output signals to
drive solid-state relays or step relays.

EN0B-0299GE51 R0104

R7426A TEMPERATURE CONTROLLER

TECHNICAL DATA

General

Electronic 8-bit microcontroller, 10-bit A/D converter, EEPROM, and LC

display
Power supply 24 Vac +10...-15%, 50/60 Hz
Power consumption 3 VA + Actuator power requirements

Temperature
Inputs

Sensor type

1)

CPA/SPA-Input

Control range
Battery

T1 Main temperature sensor
T2 Limit or cascade temperature sensor
T3 Compensation temperature sensor

Automatic identification of sensor type Temperature range Characteristics

Pt 1000
BALCO 500

NTC 20kτ -30....+85C / -30....+130C

1)

CPATYP 0

CPATYP 1 (953...1053 τ) CPA: 5 K
CPATYP 2 (100 kτ...0 τ) CPA: 5 K

0...50°C (LOw range) or 0....+130C (HI range)

Type CR2032 (life time  8 years)

accuracy 0.5 K
excluding
sensor

2)

-30....+130C 1000 τ at 0C

-30....+130C 500 τ at 23.3C

1)

20 kτ at 25C

CPA/SPA range Sensor & CPA/SPA types

CPA: 5 K

internal
T7412B1016 (Pt 1000)
T7412B1057 (Pt 1000)

T7412C1030 (Pt 1000)
T7412B1008 (NTC 20kτ)
T7412C1006 (NTC 20kτ)

CPATYP 3 (10...20 kτ) SPA: 15...30C

T7412B1024 (BALCO 500)
T7412B1040 (Pt 1000)

CPATYP 4 (0...10 kτ) CPA: 5 K

HCW 23 (setpoint wheel

printed with +/- 5 K)

CPATYP 5 (0...100 kτ) SPA: 15...30C
CPATYP 6 (0...100 kτ) SPA: 0...50C or 0...130C

43193982-001

43193982-001

Digital inputs Mode Potential free contact

Occupancy or summer/winter changeover

1)

input

Freeze protection input freeze protection operation

unoccupied or winter operation
occupied or summer operation

normal operation

open > 40 kτ

closed < 100 τ

open > 40 kτ

closed < 100 τ

Outputs ON/OFF output OFF

ON

TRIAC output

 Floating
 2 or 3-stage

1)

1)

ON (24 Vac) / OFF (0 Vac)

 Pulse-width modulation

1)

0...100%

max. load
450 mA at
24 Vac per

output

based on run time

Ambient limits

Operating temperature

Transport and storage temperature

0...50°C (0...122F

)

-35...+70°C (-31...+158F

)

Relative humidity 5...95%rh non-condensing

Safety

Protection class II as per EN60730-1
Protection standard IP30 or IP40 (front panel mounting) as per EN60529

Housing

Dimensions (H x W x D) 105 x 152 x 37 mm
Weight 250 g
Mounting Front door, back panel, wall, or rail

Connections Connection terminal terminals max. 1 x 1.5 mm

1)

Selectable

2)

same sensor type must be used for T1, T2, and T3

EN0B-0299GE51 R0104 2

2

R7426A TEMPERATURE CONTROLLER

CONTROL AND CONFIGURATION PARAMETER

The controller includes two groups of settings (A and B) for control and configuration parameters that are automatically
selected during programming. For parameter Ctrltyp = Lo setting A is selected and for parameter Ctrltyp = Hi setting B is
selected.

Control Parameter Setting A / Setting B

Parameter Description

No. Name

Low High Default

P.01 W1 Main setpoint for input T1 0 50/130 21 / 70 0.5 C
P.02 Wlim Limit setpoint (low or high) for input T2 5 / 30 50/130 16 / 90 1 C
P.03 Wcomp Compensation changeover point for input T3 -5 40 20 1 C
P.04 Wi W inter compensation authority -350 +350 0 2 %
P.05 Su Summer compensation authority -100 +100 0 1 %
P.06 Wcas Submaster or cascade setpoint OFF, 0 50/130 20/OFF 0.5 C
P.07 Rcas Cascade reset span adjustment 0 40 10 0.5 K
P.08 Xp1 Throttling range (main control loop) T1 0.5 40 2 0.5 K

P.09 Xp2

P.12 tr1
P.13 tr2

Throttling range (cascade or limit control loop)
T2

1)

Reset time (main control loop) T1 OFF, 20 s 20min OFF 10/0.5 sec/min

1)

Reset time (cascade or limit control loop) T2 OFF, 20 s 20min OFF 10/0.5 sec/min

0.5 40 10 0.5 K

P.15 Ystart Start point for mid range shift of output Y1 -20 +20 0 0.5 K
P.16 SOFFS Offset of main setpoint in Standby mode 0 10 2 0.1 K
P.17 T1Cal Calibration of temperature sensor T1 -20 +20 0 0.1 K
P.18 T2Cal Calibration of temperature sensor T2 -20 +20 0 0.1 K
P.19 T3Cal Calibration of temperature sensor T3 -20 +20 0 0.1 K
P.21 RuntimeY1 Actuator run time for Y1 6 180 60 1 sec
P.24 NightLow Night low limit against temperature extremes OFF, 8 19 / 80 OFF 1 C
P.25 NightHigh Night high limit against temperature extremes OFF, 21 40 OFF 1 C
P.26 NOFFS Offset of main setpoint in Night mode 0 30 5 / 20 0.1 K

Config. Parameter Default

Values

No. Name

C.04 Ctrltyp

2)

Lo = 0...50°C, Hi1 = 0...130°C, Hi2 = 0...130°C Lo
0 = internal (default), 1 = 5 K (953...1053 τ), 2 = 5 K (100 kτ...0 τ),

C.05 CPATYP

3 = 15 … 30C (10...20 kτ), 4 = 5 K (0...10 kτ),
5 = 15 … 30C (0...100 kτ), 6 = 0...50C or 0...130C (0...100 kτ)

C.08 Y1Mode

0= floating, 1= 2 stage ON/OFF, 2= 3 stage ON/OFF, 3 = pwm, 4 = unconfig.

(safe state is configured prior to controller's start-up)

C.12 T2ext 0 = T2 installed 1 = T1 signal used for T2 0
C.13 LimTyp 0 = Low limit 1 = High limit 0 / 1
C.14 Senstyp 0 = Auto detection 1 = NTC sensor type 0

C.15 Y1CTRF

Output Y1 used for: 0 = cooling, 1 = heating

2 = summer/winter changeover

C.16 AddHour Adjusts the month for winter/summer time change: 0 (disabled) = Min. 12 = Max. 3 month
C.17 SubHour Adjusts the month for summer/winter time change: 0 (disabled) = Min. 12 = Max. 10 month
C.18 PSTG_H3)Prestart gradient for heating: 0 (disabled) = Min. 2 = Max. 0 K/min
C.19 PSTG_C3)Prestart gradient for cooling: 0 (disabled) = Min. 2 = Max. 0 K/min
C.21
C.22
C.23

1)

for tr > 2 min resolution = 0.5 min , for tr < 2 min resolution = 10 sec

2)

actual value will not be changed during reset to default parameter

3)

can be overwritten by controller for self-adaption purposes, resolution = 0.01 K/min

Adapt

Adr

DefProg

Optimum Start Self Adaption speed: 0 = Min. 100 = Max. 50 %

2)

Serial communication address: 0 = Min. 255 = Max. 254
0 = No default programming 1 = Initiates default programming 0

Reso­lution

A / B

0

4

0 / 1

Unit

Unit

3 EN0B-0299GE51 R0104

R7426A TEMPERATURE CONTROLLER

FUNCTIONS

Real-Time Clock

The time clock performs automatic change of the controller
mode to OFF, Night, Standby, or Comfort in accordance with
the programmed time schedule. In Standby or Night mode,
the SOFFS or NOFFS is added (cooling) to or subtracted
(heating) from the calculated control point. Schedules for one
week and up to six switching points per day can be pro­grammed in advance and repeated week after week. In
addition, three different holiday schedule types H1, H2, and
H3 can be programmed. One of these holiday types can be

assigned to each holiday date of the year (01.01. ... 31.12.).

Holiday types H1 and H2 are valid only for this specific day
and are reset to normal time schedule at midnight of that day.
H3 is valid for every year and repeated year after year for
fixed holiday dates. H1 can be programmed to be in OFF
mode the whole day and H2 to be ON for a short period of
time on the last day of a longer holiday period to preheat or
precool the space in advance before the first occupied day.

Optimum Start Program

The optimum start program’s objective is to minimize total
energy consumption by calculating in room control appli­cations the start time for heating or cooling mode which will
bring its respective space temperature to the boundary of the
comfort zone at the time of occupancy start. The optimum
start program uses historical data for self-adaptive
adjustment.

Night Cycle Program

The night cycle program offers not only energy conservation,
but also the ability to assign OFF mode night low or high
limits with 1K hysteresis for the protection of a space and its
contents against temperature extremes. It automatically
cycles between the user selected upper and lower limits and
turns on full heating or cooling whenever the limits are
reached.

setpoint (CTRP1) and generates an internal deviation signal
(X

). CTPR1 is the sum of the OAT compensation effect, the

w

CPA, and the mode-dependent offset.

Depending on the deviation signal, the control output (Y1)
value is calculated and converted to a floating signal. Cooling
or heating action is selected by the configuration parameter
Y1CRTF. The ’’Throttling range’’ setting (Xp1) controls the
output span.

The startpoint Y

determines (in Kelvin) the midrange shift

start

of the output (Y1) from the calculated setpoint (CTRP1).

Limit Control (Wlim, Xp2, and tr2)

The R7426A controller offers limit control (W
performed by comparing the deviation signals of the main
and limit control loops. The lowest (low limit control) or
highest (high limit control) deviation signal is selected and
fed into the output stage.

High limit control is performed if control parameter
LimTyp = 1 and low limit control is performed if control
parameter LimTyp = 0. During limit control, the throttling
range (X

p2) and reset time (tr2) are active.

Limit control will be active only if the T2 temperature sensor
(control parameter T2ext = 0) is connected or alternatively
the sensor T1 value (control parameter T2ext = 1) is used
also for the limit control loop.

Cascade Control (W

cas

, R

and tr2)

cas

The R7426A controller provides cascade control, which uses
two control loops (master and submaster) to maintain the
master setpoint (CTRP1).

At zero room temperature deviation (X

W

charge temperature (T2) is controlled by the programmed
setpoint (W

= CTRP2). If the room temperature deviates,

cas

the submaster setpoint (CTRP2) is altered.

The reset span adjustment (R

) determines the degree of

cas

reset effect.

) which is

lim

Master), the dis-

APPLICATION

NOTE: All diagrams show proportional control action, only.

If P+I control is in operation, the slopes for heating
and cooling are not defined.

Main Temperature Control

The controller compares the actual temperature value
measured by the main sensor (T1) with the calculated

Y1

100%

EN0B-0299GE51 R0104 4

Heating Cooling

0

0

CTRP1

Xp1

Y

start

X

T1

w

C

T1

C

MASTER

Xp

CTRP1

0

CTRP2

W

R

cas

R

cas

lim

W

cas

W

lim

SUBMASTER

0

X Master

w

for
LimTyp=1

for
LimTyp=0

X Master

w

R7426B,C TEMPERATURE CONTROLLER

The integral reset time and the throttling range of the P+I
control for the submaster can be adjusted by the control

parameters tr2 and X

High limit of CTRP2 is performed if control parameter
LimTyp = 1 and low limit of CTRP2 is performed if control
parameter LimTyp = 0.

p2.

CONTROLLER FUNCTIONS

Outside Air Temperature Compensation

Outside air temperature compensation is performed when T3
is connected. The control parameter W
pensation changeover point for summer and winter compen­sation. The degree of summer and winter compensation is
defined by control parameters Wi and Su.

Winter compensation is performed if temperature
T3 < W
perature T3 > W

W1

compensated

. Summer compensation is performed if tem-

comp

C

W1

.

comp

Wi Su

defines the com-

comp

Positive

Negative

Freeze Protection

If the contact connected to the freeze protection input is open
the following actions will be executed:

Control Parameter

Y1CTRF

0 (Cooling)
1 (Heating)
2 (Cho)
2 (Cho)

In the case of controllers with RTC, the ON/OFF output will
be switched OFF.

A closed contact performs a frost recovery:

Conditions of

Outdoor Temp. T3

> 6C or
T3 not connected

< 6C

Freeze protection operation has the highest priority over all
other control operations.

Output

Function

Cooling
Heating
Cooling
Heating

Main temperature control

Setpoint W1 is temporarily raised by
Xp1 and linearly decreased to its
normal value over approx. 10min.

Freeze Protection

Action Output Y1

0%
100%
0%
100%

Frost Recovery

T3

W

comp

C

Smoothing Filter for Outside Air Temperature Input

A smoothing filter for the outside air temperature input T3 is
incorporated to eliminate sudden temperature variations. This
provides more stable operation of the control system. This

function will work only if the controller parameters have never
been changed by means of the PC tool.

Summer/Winter Changeover Function

The occupancy input can alternatively be used for summer/
winter changeover. The summer/winter changeover function
is activated by setting the control parameter Y1CTRF to 2.

A potential-free contact can be used between terminals 1 and
4 to switch the controller mode to heating (contact open) or
cooling (contact closed).

Occupied/Unoccupied Function (SOFFS)

A potential free contact can be used between terminals 1 and
4 to switch the controller between comfort (contact closed) or
standby (contact open) mode. The input is active during
Comfort and Standby mode.

In comfort mode, the temperature set point W1 is used for
the control point calculation. In standby mode, the SOFFS
parameter value is added (cooling) to or subtracted (heating)
from the calculated control point for cooling or heating.

OUTPUT FUNCTIONS

The R7426A controller provides a choice of output signals
suitable for operating a range of final control devices
according to the parameter setting of Y1Mode control
parameter.

3-Position Output for Valve or Damper Actuators
(floating mode)

The controller converts the deviation signal to a proportional
output pulse which drives the actuators depending on the
RuntimeY1 parameter value.

Parameter setting for Heating / Cooling Control Outputs:
Y1Mode = 0.

on

off

An automatic synchronization function ensures correct
positioning of the actuator. This is performed by running the
actuator to the closed position periodically. The run time for
synchronization is derived by control parameter RuntimeY1
multiplied by 1.25. Synchronization by the controller is
initiated:

 after power up reset (initial start)
 after 250 control steps as soon as control output is below

5 %

 if plant/system ON/OFF input is switched to OFF

out1

close open

stop

out2

Y1

5 EN0B-0299GE51 R0104

R7426A TEMPERATURE CONTROLLER

2-Stage ON/OFF Sequence Control

The R7426A controller converts the output signal into a two­stage ON/OFF sequence output signal suitable for operating
relays. Two relays can be connected to provide sequence
control of e.g. two electric heater stages.

Parameter setting for Output Switching Position:
Y1Mode = 1

on

off

Step1 on

25 65 70

30

Step2 on

100

Power

out2
out1

%

Y1

3-Stage Binary ON/OFF Sequence Control

The R7426A controller converts the heating signal into a
3-stage binary ON/OFF sequence as shown in the following
diagram.

Parameter setting for Output Switching Position:
Y1Mode = 2

Step2 on

Step1 on

on

off

25

Step3 on

75

70 100 %20 5045

Power

out2
out1

Y1

If one of the following conditions occur, the controller
switches the ON/OFF output from ON to OFF:

 The controller mode = OFF.
 The freeze protection input is active.
 The following function will be active in flow water

temperature applications if the configuration parameter
Ctrltyp = Hi2:
The controller switches the ON/OFF output from ON to
OFF if the outside air temperature is above 8C and the
output signal Y1 = 0% for more than 5 minutes during
Comfort, Standby, or Night mode.

ADJUSTMENTS

Control Point / Setpoint Adjustment
(CPATYP)

The control or setpoint can be adjusted via the internal or an
external potentiometer connected to the CPA/SPA input. The
CPA/SPA type is selected by the control parameter CPATYP
(see page 2, Technical Data).

Calibration of Temperature Sensors
(T1CAL, T2CAL, and T3CAL)

In case of an offset as a result of long wiring lengths the
temperature sensor inputs (T1, T2, and T3) can be adjusted
separately by the control parameters T1CAL, T2CAL, and
T3CAL.

Electric Heat Current Valve (pwm output)

The pulse-width modulated output is suitable for driving
electric heat current valves and is controlled from the heating
signal. The interval or total cycle time is set by the control
parameter RuntimeY1.

The diagram below shows as example, 60% Output Signal
with Motor RuntimeY1 set to 50 sec:
Y1Mode = 3.

out1/out2

on

off

30 50 70 80 100 sec

Y1

ON/OFF Output

The ON/OFF output is provided to switch fans, pumps, or
other MicroniK 200 controller without RTC.

If one of the following conditions occur, the controller
switches the ON/OFF output from OFF to ON after a fixed 3­minute time delay:

 The controller mode OFF (Comfort Standby or Night

mode).

 The night cycle program is active.

WIRING

Wiring run

From controller to all
input and output
devices

Offset for temperature sensors due to wire resistance per
10 m distance from sensor to controller:

Type of wire

2

0.5mm

(AWG20)

1.0mm

(AWG17)

1.5mm

(AWG15)

2

2

(0.324F)

(0.162F)

(0.108F)

Type of

wires

local
standard

Temperature offset

Pt 1000 BALCO 500 NTC

0.18C

0.09C

0.06C

(0.54F)

0.15C

(0.27F)

(0.18F)

Length max.

2

1.0mm

100 m 150 m

0.3C

negligible

0.1C

1.5mm

2

EN0B-0299GE51 R0104 6

CONNECTIONS

R7426A TEMPERATURE CONTROLLER

24 V

R7426A

15
16
17

24V

18
19

2

20

n

p

e

o

24V

21
22

s

c

o

l

23
24
25
26
27
28

4

V

U

O

/

U

O

/

e

2

T

1

Y

1

T

*

R7426A2014

R7426A1016

ON/OFF

24V

On/Off Output

or Summer/Winter
Changeover

CPA/SPA

T1

T2

T3

10
11

12

B

13

A

14

= 0V

9

10

1

Occupancy

2
3

4
5

6
7

T1

T2

W 303

T3

8
9

*

Freeze
prot.

c

r

a

f

e

t

n

I

a

i

l

e

r

S

r

o

f

s

u

B

l

n

e

a

P

Jumper1)State Description

W303

1)

Default jumper position = closed

2)

e

Only cut (open) jumper W303 if the T3 input is fed from

open

closed

2)

T3 supplied by this controller
T3 supplied from another controller

another controller (parallel connection, max. 6 devices).
This disconnects the T3 input from the internal power
supply.

CAUTION

 Outputs are not isolated from power supply
 Observe correct phasing with 24 Vac power

supply

Fig. 3. Connections and Jumper coding

7 EN0B-0299GE51 R0104

R7426A TEMPERATURE CONTROLLER

87 +

/-0.

2

MOUNTING AND DIMENSIONS

All dimensions in mm.

121 +/- 0.3

= =

==

3.5

105

152

Honeywell

SEL

SET

198 +/-0.3

170 +/-0.3

= =

43

==

approx. 45 x 35

(cut-out for cables)

3.5

wall mounting

Automation and Control Solutions

Honeywell GmbH
Böblinger Straße 17
D-71101 Schönaich
Phone: [phone]
Fax: [phone]
http://europe.hbc.honeywell.com

(when mounting on DIN rail)

4.5

front panel mounting

Fig. 4. Mounting and dimensions

180 +/-0.2

110 + / -0.3

HONEYWELL

130 +/-0.3

Subject to change without notice. Printed in Germany Manufacturing location certified to

EN0B-0299GE51 R0104