EXD-U01 Stepper Motor Controller
Technical Bulletin The EXD-U01 stepper motor controller enables the use of Emerson's electronic valves EX4...EX8 & CX4...CX7 as:
Features
- Analog input signal: 4...20 mA or 0...10 V
- "Plug and Run": Ready for operation immediately after mounting and connection; parameter input not required
- Simple configuration via DIP switches
- Digital input for closing the valve
- Aluminum housing for DIN rail mounting
- Simple wiring
- Tested and ready for operation
- Compatible with EXD-U00
Selection Table
| Type | Part No. | Description |
|---|---|---|
| EXD-U01 | 804750 | Stepper motor controller without terminal set |
| EXD-U01 Contr.Kit | 808052 | Terminal set for EXD-U00 |
| K09-U00 | 804559 | Stepper motor controller kit incl. terminals |
| ECP-024 | 804558 | Uninterruptible power supply |
| K09-P00 | 804560 | Terminal set for ECP-024 |
Function
The stepper motor controller requires an analog input signal of 4...20 mA or 0...10 V. The EX/CX series valve is opened or closed proportionally to this input signal, controlling the flow rate of liquid or gaseous refrigerant. The stepper motor controller can be connected to any controller that generates a 4...20 mA or 0...10 V control signal. System developers can thus connect different controllers with the stepper motor controller to achieve the desired function. At an input signal of 4 mA or 0 V, the valve is fully closed; at 20 mA or 10 V, it is open.
Input Signal vs. Valve Opening
A graphical representation shows the relationship between the analog input signal and the valve opening degree. The X-axis represents the valve opening degree from 0% to 100%. The Y-axis shows the analog input signal. A line indicates that 0 V or 4 mA corresponds to 0% opening, and 10 V or 20 mA corresponds to 100% opening.
Option: Uninterruptible Power Supply ECP-024
The optional uninterruptible power supply ECP-024 contains a rechargeable acid-gel lead-acid battery, providing enough energy for a maximum of two EXD-U01 units to close the valve(s) in case of a power failure.
Shut-off Function and Start/Stop Command
The shut-off function of the step motor-controlled valves in the EX and CX series eliminates the need for an additional solenoid valve. The digital input allows the valve to be closed at any time, independent of the input signal.
Digital Input Function
In normal operation, the digital input is switched on and off together with the compressor; the pump-down function is switched like a solenoid valve. The status of the digital input depends on the desired operating state.
Digital Input Operation Table
| Case | Operating State | Digital Input |
|---|---|---|
| I | Compressor starts | 24 V |
| I | Compressor stops | 0 V |
| II | Pump-down function, when heating/cooling is no longer required | 0 V during compressor operation |
| II | End of pump-down cycle | 0 V maintained after compressor stop |
Pump-down Function
Emerson control valves can be closed while the compressor pumps down the refrigerant. The pump-down function is controlled by the system controller.
Configuration
The valve type and analog input (0...10 V or 4...20 mA) are selected using the DIP switches according to the table and diagram.
DIP Switch Configuration Table
| Valve / Analog Input | DIP Switch Number | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|---|
| EX4-6 | OFF | ON | ON | OFF | ON | OFF | ON | OFF | |
| CX4-6 | OFF | ON | ON | OFF | ON | OFF | OFF | OFF | |
| EX7 | ON | OFF | OFF | ON | OFF | ON | ON | ON | |
| CX7 | ON | OFF | OFF | ON | OFF | ON | OFF | OFF | |
| EX8 | ON | ON | OFF | ON | ON | ON | ON | ON | |
| 4-20 mA | OFF | - | - | - | - | - | - | OFF | |
| 0-10 V | OFF | - | - | - | - | - | - | ON |
Technical Data
EXD-U01 Stepper Motor Controller
| Supply voltage | 24 VAC ±10%, 50-60 Hz |
| Current consumption | 1.0 A external fuse recommended |
| Rated power | 10 VA (together with EXV) |
| Temperature: Storage | -20...+65°C |
| Temperature: Operation | 0...+60°C |
| Humidity | < 90% RH, non-condensing |
| Protection class | IP20 |
| Approvals | EMC: EN 61326-1, EN50081, EN50082 |
| Marking | CE EAC |
| Analog input signal | 4-20 mA |
| Input resistance | 364 Ω |
| Analog input signal | 0-10 V |
| Impedance | 127 kΩ |
| Digital input | 24 VAC ±10%, 50-60 Hz |
| Connection EX4...EX8 | 24 VDC ±10% |
| Connection | With 4-wire cable, AWG20/22 |
| Mounting | Screw terminals, wire Ø 0.5-2.5 mm² |
| Housing material | Aluminum |
Optional Uninterruptible Power Supply ECP-024
| Battery type | Acid-gel lead-acid accumulator |
| Included accumulators | 2 pieces x 12 VDC, 0.8 Ah |
| Supply voltage | 24 VAC ±10%, 50-60 Hz |
| Output voltage UB | 18 VDC |
| Outputs | For two controls |
| Charging time | Approx. 2 hours |
| Approvals | EMC: EN 61326-1, EN50081, EN50082 |
| Marking | CE |
| Temperatures: Storage | -20...+65°C |
| Temperatures: Operation | -10...+60°C |
| Humidity | < 90% RH, non-condensing |
| Connection | Screw terminals for wire Ø 0.5-2.5 mm² |
| Mounting | DIN rail mounting |
| Protection class | IP20 |
| Housing material | Aluminum |
Application of EXD-U01 in CO2 Booster Systems
In conjunction with the CX and EX series, the EXD-U01 offers variants for systems with CO2 subcritical and transcritical operation and function.
Application Table
| Valve Type | PS [bar] | PT [bar] | Transcritical | Subcritical | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| High-pressure gas valve | Heat recovery | Hot gas | Bypass valve | Heat recovery | Hot gas | Expansion valves | Suction line | |||
| CX4...CX7 | 120 | 172 | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| EX4...EX7 | 60 | 66 | - | Yes | Yes | - | Yes | Yes | Yes | Yes |
| EX8 | 45 | 49.5 | - | Yes | Yes | - | Yes | Yes | Yes | Yes |
Wiring Diagram
The wiring diagram shows the EXD-U01 stepper motor controller and the optional ECP-024 uninterruptible power supply. It details the connections for power supply (24 V AC/DC), stepper motor, digital input, and analog input. Terminal designations (1-8) and their functions are illustrated. The diagram also shows the ECP-024 providing 18V DC to the EXD-U01 and its battery connection. Wire color codes (WH, BK, BL, BN) are specified for connections.
Diagram Explanations
- 1. Power supply
- 2. Transformer
- 3. Fuse
- 5. Cable connector unit EXV-Mxx for connecting EX4...EX8 valves; CX4 ... CX7
- 6. Control signal 4...20 mA or 0...10 V
- 7. Digital input (0 V = Off, 24 V = On)
- 8. Analog input (4...20 mA or 0...10 V)
- 9. Optional uninterruptible power supply closes the valve during a power failure if the application requires a valve with a shut-off function.
Wire Colors
- WH: White
- BK: Black
- BL: Blue
- BN: Brown
Dimensions
Dimension drawings are provided for the EXD-U01 and ECP-024 units. The EXD-U01 measures 90 mm in width, 73 mm in height, and 63 mm in depth. The ECP-024 measures 169 mm in width, 73 mm in height, and 63 mm in depth.
