Danfoss EIM 336 Data sheet

Data Sheet

Superheat controller

Type EIM 336

For stepper motor valves

The EIM 336 is a superheat controller that can be used to control the opening degree of a valve based on the superheat of the evaporator. This is applicable in applications such as air conditioning, heat pumps and refrigeration.

An alternative option is to use the controller in manual mode via modbus communication and use it as a valve driver by setting the valve opening degree manually.

Benefits

• The evaporator is charged optimally even when there are large variations in load and suction pressure.

• The superheat control can save energy by ensuring optimum utilization of the evaporator.

• The superheat is controlled to the lowest stable value.

• It controls EEV in microsteps providing a smooth superheat curve and less noise.

Features

• Minimum Stable Superheat search regulation (MSS).

• Maximum Operating Pressure function (MOP).

• Defrost.

• Compressor protection functions.

• Evaporator temperature (Te) control for de-

humidifying.

• Valve driver via Modbus Communication.

• Loss Of Charge indication (LOC).

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Superheat controller, Type EIM 336

1 Portfolio overview

Table 1: Related products

Pressure transducer	Temperature sensor	Programming key / display	Electric Expansion valve
DST P110, AKS 32R, NSK BExx	AKS 21, AKS 11	MYK - EIM interfacer	ETS6

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Superheat controller, Type EIM 336

2 Functions

2.1 Acronyms and abbreviations

LOC Loss of charge indication

SH Superheat

MOP Maximum operating pressure

MSS Minimum stable superheat

Te Saturated suction temperature

Pe (Po) Evaporator pressure

S2 Evaporator refrigerant outlet temperature

S4 Evaporator medium outlet temperature

OD Opening degree

PNU Parameter number - is equivalent to the modbus register no. (modbus adress + 1)

2.2 Functions

Minimum Stable Superheat (MSS)

The controller will search for the minimum stable superheat between an upper and lower boundary set by the user. If the superheat has been stable for a period of 6 minutes, the superheat reference is decreased. If the superheat becomes unstable, the reference is raised again. This process continues as long as the superheat is within the bounds set by the user. The purpose of this is to search for the lowest possible superheat that can be obtained while still maintaining a stable system. The superheat reference can also be fixed, in which case this function is disabled.

Maximum Operating Pressure (MOP)

In order to reduce the strain on the compressor, a maximum operating pressure can be set. If the pressure comes above this limit the controller will control the valve to provide a lower pressure instead of a low superheat. The limit for this function is usually a fixed pressure, but it is possible to offset the limit temporarily.

Evaporator temperature (Te) control for de-humidifying

A function is provided to control on the evaporator temperature instead of the superheat. This can be used to dehumidify the air flowing through the evaporator. By lowering the evaporators surface temperature, the water vapor in the air is condensed.

Superheat close

When the superheat is below a set minimum value, the valve will close faster in order to protect the compressor from the risk of getting liquid in the suction line.

Manual control

The valve can be controlled manually by setting the desired opening degree via modbus.

Start/stop of regulation

The start or stop of the regulation can be controlled by setting the software main switch, which is accessible via modbus. It is however also possible to use a digital input from an external Regulation control On / Off switch.

Loss Of Charge indication (LOC)

A function is provided to indicate loss of refrigerant charge. This is only indicated by setting an alarm flag which can be accessed via modbus. No special action is performed by the controller.

External sensor values

The EIM 336 has sensor inputs for the suction pressure and evaporator temperature (S2). It is however possible to substitute these sensor inputs by sending external sensor values via modbus. These external values need to be updated frequently.

Forced opening during startup

In some applications it is necessary to open the valve quickly when the compressor turns on, to prevent too low suction pressure. This is ensured by setting a fixed opening degree and a startup time for the controller. Note that this will give a fixed opening degree for the duration of the start time, regardless of the superheat value.

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Superheat controller, Type EIM 336

Forced opening during off

In some applications the valve must remain open when the controller is off. This can be done by setting a fixed opening degree. When normal control is switched off with the main switch, the valve will keep this opening degree.

Defrost handling

The controller does not itself handle defrost of the evaporator. It is however possible to enter a special defrost sequence, which will overrule the normal control of the valve.

Standalone function

The EIM 336 is designed to operate in conjunction with a system master controller, which will control the EIM 336 via modbus. It is however possible to use it in a standalone mode with no external control, except a digital input from the Regulation control On / Off switch. In this configuration some of the other functions will not be available.

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Superheat controller, Type EIM 336

3 Applications

3.1 Regulation control

The evaporator superheat is controlled by one pressure sensor Pe (evaporator pressure) and one temperature sensor S2 (refrigerant temperature). Alternatively the pressure and temperature signals can be received as data via modbus. This can be useful if the pressure and temperature sensors are mounted on a separate controller.

Fitting the S4 (evaporator medium outlet temperature) is optional and has no effect on regulation, it is a readout value only. S4 can however be setup as a Regulation control On / Off switch instead to provide an external ON/OFF function for the controller.

Figure 1: Regulation control

		<![if ! IE]> <![endif]>Danfoss 80G39.12
	EIM 336
	AKS32R
	AKS 11	ETS 6
	Evaporator	ETS 6
	Evaporator

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Superheat controller, Type EIM 336

4 Product speci€cation

4.1 Technical data

Table 2: Technical data

Features	Description
Supply voltage	24 V AC / DC (± 15%), 50 / 60 HZ, 15 VA / 8 Watt, Class II isolation

Power consumption	Idle	Max. 150 mA @ 24 V DC
Power consumption	Operating	Max. 150 mA @ 24 V DC
	Operating	Max. 150 mA @ 24 V DC

Input signals	Po	AKS 32R (or similar ratiometric pressure transmitter)
Input signals
For the EMC compliance, sensor cable length must be < 3m / 118 in.	S2	PT1000 (measuring range -60 – +120°C / -76 – 248 °F)
For longer sensor cable, a ferrite bead should be used.	S4	PT1000 or digital input from external contact.
	S4	PT1000 or digital input from external contact.
EEV driver	Max. current 150 mA RMS
EEV driver	Max. current 150 mA RMS
EEV	Unior bipolar coil with JST XHP-5 connector
Data communication	RS485 – Modbus RTU (Not terminated internally)
	Storage: -34 °C to 71 °C / -30 °F to 160 °F
	Storage: -34 °C to 71 °C / -30 °F to 160 °F
Environment	Operating: -25 °C to 60 °C / -13 °F to 140 °F
	Humidity: <95% RH, non condensing
Dimensions	25 × 50 × 80 mm / 0.98 × 1.97 × 3.15 inch
Dimensions	25 × 50 × 80 mm / 0.98 × 1.97 × 3.15 inch
Operation	Stand alone or via Modbus data communication

4.2 Connections

Figure 2: Stand alone con€guration

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	P		3
			3
V			1		T
V
+ -
						C
<![if ! IE]> <![endif]>PWR	<![if ! IE]> <![endif]>COM	<![if ! IE]> <![endif]>ADR	<![if ! IE]> <![endif]>PO	<![if ! IE]> <![endif]>S2	<![if ! IE]> <![endif]>S4	<![if ! IE]> <![endif]>EEV
						E

V Power Supply 24 V AC or DC

PPressure transmitter Ratiometric 0.5 – 4.5 V i.e. AKS 32R

T Temperature sensors PT 1000 i.e. AKS 11

CRegulation control On/Off switch (Enable parameter HW Main Switch to 1)

EElectric expansion valve ETS 6 with JST-XHP 5 connector

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Superheat controller, Type EIM 336

Figure 3: System con€guration (default factory settings)

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		2
	P		3
			3
			1		T
			1
V
+ -	M
	M
	TxD -					C
	TxD+
	D
<![if ! IE]> <![endif]>PWR	<![if ! IE]> <![endif]>COM	<![if ! IE]> <![endif]>ADR	<![if ! IE]> <![endif]>PO	<![if ! IE]> <![endif]>S2	<![if ! IE]> <![endif]>S4	<![if ! IE]> <![endif]>EEV
						E

V Power Supply 24 V AC or DC

PPressure transmitter Ratiometric 0.5 – 4.5 V i.e. AKS 32R

M Modbus to master controller

T Temperature sensors PT 1000 i.e. AKS 11

CRegulation control On/Off switch (Enable parameter HW Main Switch to 1)

EElectric expansion valve ETS 6 with JST-XHP 5 connector

IMPORTANT:

•The supply voltage is not galvanically separated from the input and output signals, hence it is not recommended to use shared power supply.

•No voltage should be supplied externally, if S4 terminal is setup as a Regulation on/off switch.

•Do not reverse the polarity of the power connection cables or Modbus signal cable else it could damage the terminals.

Figure 4: Modbus one to one connection

RS485 (+)
M
<![if ! IE]> <![endif]>PWR	<![if ! IE]> <![endif]>COM
RS485 (-)	A
	A

Figure 5: Modbus in Daisy Chain

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<![endif]>Danfoss 80G166.10

RS485 (+)		RS485 (+)
M
<![if ! IE]> <![endif]>PWR	<![if ! IE]> <![endif]>COM		<![if ! IE]> <![endif]>PWR	<![if ! IE]> <![endif]>COM
RS485 (-)	A	RS485 (-)	B	<![if ! IE]> <![endif]>Danfoss 80G165.10
	A		B	<![if ! IE]> <![endif]>Danfoss 80G165.10

M	Master controller	B	EIM slave 2

A	EIM slave 1	R	120 Ohm min. 0.25 Watt

NOTE:

•If two EIMs are connected remember to remove the addressing jumper on one of the EIMs.

•Modbus transmission lines usually require termination resistors, especially for longer cable lengths.

4.3 Settings

4.3.1Setting controller in Superheat control mode

NOTE:

Make sure that r12 = 0 (OFF) and change the settings. The setting will depends on the system requirement.

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Superheat controller, Type EIM 336

Table 3: Setting controller in Superheat control mode.

Features	Description
Enabling Regulation control ON/Off switch	HwMainSwitch = 1 (default is 0, i.e S4 sensor)
Enabling Regulation control ON/Off switch	For standalone configuration it is recommended to enable Regulation control ON/Off switch in order to control start/
(optional)
(optional)	stop regulation when needed, otherwise the controller will start regulating when controller is powered up.

Select Refrigerant	o30	= 1 - 42 (default value is 20 i.e R407C)
	n37	= 384 x 10 micro step (3840 micro steps = 480 half steps).
Select valve setting(optional)	n38	= Max. steps/sec, default value is 31 half steps
	For other valve type than Danfoss check the technical spec. of the valve.
Define pressure sensor range in bar absolute	o20	= Min. Transducer pressure
(x10)	o21	= Max. Transducer pressure
	n10	= min. superheat reference
Define min/max superheat	n09	= max. superheat reference
	For fixed superheat define n09 = n10
Define MOP (optional)	n11	= maximum operating pressure (default is 12.5 bar absolute, max. 200 = MOP off)
Set force opening of the valve ( optional)	Start OD% (n17 )
Set force opening of the valve ( optional)	StartUp time (n15)
	StartUp time (n15)
To start the superheat control	Set r12= ON

4.3.2Setting controller in valve driver mode using Modbus signal

NOTE:

Make sure that r12 = 0 (OFF) and change the settings so they fit to their application.

Table 4: Setting controller in valve driver mode using Modbus signal

Features	Description
Select Application mode	o18 (PNU 2075 )= 1 i.e Manual control
Select valve setting(optional)	n37	= 384 x 10 micro step (3840 micro steps = 480 half steps).
	n38	= Max steps/sec, default value is 31 half steps
	for other valve type than Danfoss check the technical spec of the valve
Select Manual opening degree	o45 Manual OD % (PNU 2064)
	0 = fully closed, 100 = fully open.

By changing parameter o45 Manual OD, the valve will move accordingly regardless of r12 parameter value.

4.3.3 Selecting a refrigerant

The controller needs to know which refrigerant is used in order to accurately control the superheat. This can be selected by setting the “o30 Refrigerant” to the desired refrigerant as defined in the list below.

If no refrigerant is selected (“o30 Refrigerant” is set to 0 meaning the refrigerant is undefined), the “No Rfg. Sel.” alarm is set and the controller will not start regulating.

Refrigerant setting

Before refrigeration can be started , the refrigerant has to be defined. You can select the following refrigerant.

Table 5: Related parameters

Symbolic name	PNU	Description
		1	= R12	10	= R503	19	= R404A	28	= R744	37	= R407F
		2	= R22	11	= R114	20	= R407C	29	= R1270	38	= R1234ze
		3	= R134a	12	= R142b	21	= R407A	30	= R417A	39	= R1234yf
		4	= R502	13	= User defined	22	= R407B	31	= R422A	40	= R448A
o30 Refrigerant	2551	5 = R717		14	= R32	23	= R410A	32	= R413A	41	= R449A
		6	= R13	15	= R227	24	= R170	33	= R422D	42	= R452A
		7	= R13b1	16	= R401A	25	= R290	34	= R427A
		8	= R23	17	= R507	26	= R600	35	= R438A
		9	= R500	18	= R402A	27	= R600a	36	= Opteon XP10

WARNING:

Wrong selection of refrigerant may cause damage to the compressor.

4.3.4 Connecting and setting up a valve

The EIM 336 controller is designed to be used with Danfoss ETS 6 valves with a maximum of 480 pulses from fully closed to fully open. This setting should not be changed.

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Superheat controller, Type EIM 336

The speed of the valve can be changed by increasing or decreasing the number of pulses per second, “n38 Max StepsSec”. A larger value will make the valve open or close faster. Note that the torque of a stepper motor decreases as the speed increases. Too high speeds should therefore be avoided. For the ETS 6 valve, the recommended speed setting is 31 pulses per second.

When the controller is powered, the valve will first be closed fully so that the controller starts from a known opening degree (0%). In order to make sure that it is fully closed, the valve will be closed 100% plus an additional contribution known as start backlash. The start backlash takes into account that the stepper motor may loose some steps due to too low torque or mechanical slippage in the gears etc. The start backlash is the amount of extra steps in percent to close once the valve is closed (less than 1%). If the valve is opening and reaches its destination, it will move additional steps in the opening direction, then move the same amount of steps in the closing direction. This is called backlash and is the amount of steps to add to compensate for spindle play.

Table 6: Related parameters

Symbolic name	PNU	Description
n38 Max. Steps Sec.	3033	Steps per second
n39 Start BckLsh	3034	Backlash, is the additional amount of steps, in percent, to close at startup and when the valve opening de-
n39 Start BckLsh	3034	gree is less than 1%.
		gree is less than 1%.
n40 Backlash	3035	Start Backlash is the amount of steps to compensate for spindle play.

4.3.5 Connecting and setting up a pressure sensor

The pressure sensor input is setup by default to accept an AKS32R pressure transducer. If another sensor is to be used, it is important to note that it needs to be a 0.5 - 4.5 V d.c. ratiometric type (10% - 90% of supply voltage).

The default range for the sensor is 0 to 16 bar absolute. This can be changed by setting the minimum transducer pressure, “o20 MinTransPres” and the maximum transducer pressure, “o21 MaxTransPres” to the new values. The values must be entered in bar absolute so a sensor with a range of -1 to 12 bar gauge, needs to bedefined as 0 to 13 bar absolute.

Table 7: Related parameters

Symbolic name	PNU	Description
o20 MinTransPres	2034	Minimum transducer pressure (in bar absolute x 10). Example: 0 bar absolute is entered as 0
o21 MaxTransPres	2033	Maximum transducer pressure (in bar absolute x 10). Example: 13 bar absolute is entered as 130

NOTE:

Both Danfoss AKS 32R and Danfoss Saginomiya Pressure transmitter NSK-BExxx follows the relative (gauge) pressure, therefore same rules applies as explained above in converting and defining it in bar absolute in EIM controller.

Mounting pressure transmitter

Installation of the pressure transmitter is less critical, but mounting of pressure transmitter should be closer to the temperature sensor, right after the evaporator and with its head in upright position.

Power supply:

•Grounding of secondary (output) of transformer is not recommended.

•Do not reverse the polarity of the power connection cables and avoid ground loops (i.e. avoid connecting one field device to several controllers as this may result in short circuits and can damage your device).

•Use individual transformers for EIM 336 controller to avoid possible interference or grounding problems in the power supply.

WARNING:

•Separate the sensor and digital input cables as much as possible (at least 3 cm) from the power cables to the loads to avoid possible electromagnetic disturbance.

•Never lay power cables and probe cables in the same conduits (including those in the electrical panels).

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