Honeywell R7426A Output Signal Mode YMode C.11, Supply of Temperature Signal T2 T2ext C.12

R7426A,B,C TEMPERATURE CONTROLLER WITH AND WITHOUT REAL TIME CLOCK

Output Signal Mode YMode (C.11)

Sequence Operation

The controllers R7426B,C are supplied from the factory configured for sequence operation of heating, mixed air, and cooling control.

The sequence operation can be configured for the following control applications by the control parameters YMode and Y1CTRF (see Table 8). Sequence control will be activated if at least one control parameter YxMode is not equal 4 (R7426B, only).

Table 8. Sequence Operation Selection

sequence control	YMode	Y1CTRF	YxMode
for cooling with three outputs	1	0	0
(Y1, Y2, Y3)
for heating with three outputs	1	1	0
(Y1, Y2, Y3)
with two outputs (Y1, Y3) for
heating and one output for	2	n.a.	0
cooling (Y2)
with one output (Y2) for
heating and two outputs for	3	n.a.	0
cooling (Y1, Y3)
damper, cooling and heating	0	0	0
(Y1, Y2 and Y3)
energy recovery, cooling and	0	1	0
heating

Multistage ON/OFF Function

In the case of the three floating output controller R7426B, several ON/OFF sequence control functions can be selected by the configuration parameter YMode (see Table 9).

Table 9. Multistage Selection

						provided	function
		output function		YMode	YxMode	by
							of Y2
						output
	6-stage ON/OFF		1		4 (x=1, 2,	Y1,Y2,Y3	n.a.
	sequence control				and 3)
	4-stage ON/OFF				4 (x=1
	sequence control		2			Y1,Y3
					and 3)
	heating
	4-stage ON/OFF				4 (x=1		according
	sequence control		3			Y1,Y3
					and 3)		to
	cooling
							Y2Mode
	15-stage binary
	coded ON/OFF		5		n.a.	Y1,Y3
	sequence control
	H.
	two-position		4		n.a.	Y1	Y2 and
	damper control						Y3 1)
1)		individual (cooling and heating)

In the case of the R7426B,C controller, the output Y1 can be configured for two-position damper control by setting the configuration parameter YMode to 4.

Supply of Temperature Signal T2

T2ext (C.12)

If sensor T1 is used also for high or low limit control, the con- figuration parameter T2ext must be set to 1. This inter- connects the T1 and T2 input internally and the sensor has to be connected only to the T1 input.

By using a limit temperate sensor T2, the parameter T2ext has to be set to 0 (default).

Limit Type LimTyp (C.13)

The configuration parameter LimTyp allows the selection of high or low limit control. High limit control is performed if configuration parameter LimTyp = 1; low limit control is performed if configuration parameter LimTyp = 0.

Sensor Type Senstyp (C.14)

Three different sensor types can be used with the controller (see Table 10).

Table 10. Sensor Types

automatic ID	temperature	characteristics
of sensor type	range
Pt 1000	-30....+130°C	1000Ω at 0°C
BALCO 500	-30....+130°C	500Ω at 23.3°C
NTC 20kΩ	-30....+85°C /	20kΩ at 25°C
	-30....+130°C1)

1) NTC sensor is detected automatically if, during power- up, the sensor temperature is within -30....+85°C and the

configuration parameter Senstyp = 0. NTC sensor is selected manually if the configuration parameter Senstyp is set to 1.

Automatic identification of sensor type is selected if the configuration parameter Senstyp = 0 (default). After power up reset, the controller detects automatically the type of sensor connected to the main temperature input T1. For correct auto detection, it is necessary that the measured temperature be in the specified range (see Table 10). The same type of sensor must be used for all temperature inputs (T1, T2 and T3).

Output Control Function Y1CTRF (C.15)

The R7426A controller performs cooling control if the configuration parameter Y1CTRF is set to 0. A rise in the measured variable will increase the output value (direct acting). The control action must be reversed for heating control by setting the control parameter Y1CTRF to 1. A rise in the measured variable will decrease the output value.

If the configuration parameter is set to 2, the R7426A controller provides summer/winter changeover control by a potential-free contact connected to the occupancy input (terminals 1 and 4).

In the case of the R7426B,C controller, the configuration parameter Y1CTRF has to be set to 0 (default) to perform mixed air damper control and to 1 for energy recovery systems.

7 EN1B-0203GE51 R0507C