Emerson EXD-SH1/2 Controller with ModBus Communication for Electrical Control Valves
Operating Instructions
General Information
The EXD-SH1/2 controllers are stand-alone superheat and/or temperature controllers. The EXD-SH1 is intended for the operation of one bipolar electrical control valve, whereas the EXD-SH2 is designed for the operation of two independent bipolar electrical control valves. A table of available application possibilities is listed below:
| Controller | Circuit 1: Main function | Circuit 2: Main function |
|---|---|---|
| EXD-SH1 | Superheat or temperature control | - |
| EXD-SH2 | Superheat or temperature control | Superheat Control |
Notes: It is possible to use only circuit 1 from EXD-SH2. In this case, circuit 2 must be disabled (C2 parameter) and the sensors and valve for the second circuit are not needed. ModBus communication is described in a Technical Bulletin and is not covered by this document.
Technical Data
- Power supply: 24VAC/DC +10%/-10% 50/60HZ
- Power consumption: EXD-SH1: 25VA, EXD-SH2: 50VA
- Plug-in connector: Removable screw terminals, wire size 0.14...1.5 mm²
- Protection class: IP00
- Temperature sensors: ECN-N.../TP1... (temperature range down to -45°C), ECN-Z... (temperature range down to -80°C ultra low temperature)
- Allowable operating/surrounding temperature: 0...+55°C
- Maximum cable distance between EXD-SH and EXD-PM: 50 cm (AWG 18 wire size, ≥ 1mm²)
- Pressure sensors: PT5N, PT5N-FLR or ratiometric probes
- Output alarm relay current rating: Resistive Load 24 V AC/DC, 1 A; Inductive Load 24 V AC/DC, 0.5 A
- Contact is closed: During alarm condition
- Contact is open: During normal operation and supply power OFF
- Valves: Stepper motor output CV4-7
- Mounting: For standard DIN rail
- Marking: CEEAC
Warning: EXD-SH1/2 (EXD-PM, ECP-024) has a potential ignition source and does not comply with ATEX requirements. Installation only in non-explosive environment. For flammable refrigerants, only use valves and accessories approved for it!
Dimensions (mm)
A visual representation of the dimensions is provided, showing a rectangular unit with specific measurements for length, width, and height. The main body is approximately 70mm in length, 35mm in width, and 117.5mm in height. There are also specific cutouts and mounting points indicated.
Safety Instructions
- Read operating instructions thoroughly. Failure to comply can result in device failure, system damage, or personal injury.
- It is intended for use by persons having the appropriate knowledge and skill.
- Before installation or service, disconnect all voltages from the system and device.
- Do not operate the system before all cable connections are completed.
- Do not apply voltage to the controller before completion of wiring.
- Entire electrical connections must comply with local regulations.
- Inputs are not isolated; potential-free contacts need to be used.
Electrical Connection and Wiring
- Refer to the electrical wiring diagram for electrical connections.
- Note: Keep controller and sensor wiring well separated from supply power cables. Minimum recommended distance: 30 mm.
- When connecting the wires of the EXV-M... (electrical plug of valves), consider the color coding as follows: EXV-M...: WH: White; BK: Black; BN: Brown; BL: Blue
- The digital input DI1 (EXD-SH1/SH2) and DI2 (EXD-SH2) are the interfaces between EXD-SH1/2 and the upper-level system controller if ModBus communication has not been used. The external digital inputs must be free of potential (dry contact) and shall be operated in function system's compressor/demand.
| Operating condition | Digital input status |
|---|---|
| Compressor starts/run | External contact to be closed (Start) |
| Compressor stops | External contact to be open (Stop) |
Note: Connecting any EXD-SH1/2 inputs to the supply voltage will permanently damage the EXD-SH1/2.
Temperature Setting in Normal Sense (Controller function as temperature controller)
A graph illustrates the relationship between valve opening percentage and temperature. As temperature increases, valve opening decreases. The graph shows setpoints for 1tAL, 1tbd, 1tst, and 1tAH.
Temperature Setting in Reverse Sense (Controller function as temperature controller)
A graph illustrates the relationship between valve opening percentage and temperature. As temperature increases, valve opening increases. The graph shows setpoints for 1tAL, 1tbd, 1tst, and 1tAH.
Disposal
Electrical and electronic waste must NOT be disposed of with other commercial waste. Instead, it is the user's responsibility to pass it to a designated collection point for the safe recycling of Waste Electrical and Electronic Equipment (WEEE directive 2012/19/EU). For further information, contact your local environmental recycling center.
Wiring Options
Diagrams show various wiring configurations including:
- UPS (ECP-024) / Supercap (EXD-PM) for one or two controllers.
- Connection of EXD-M... plug & cable.
- Connection of temperature sensors (ECN-N.../TP1..., ECN-Z...) and pressure transmitters (PT5N...).
- Diagrams illustrating the use of a single supercap for one EXD-SH1 and two supercaps for one EXD-SH2.
Warning: Use a Class II category transformer for 24VAC power supply. Do not ground the 24VAC lines. It is recommended to use individual transformers for EXD-SH1/2 controllers and for third-party controllers to avoid possible interference or grounding problems in the power supply. If EXD-PM is connected, it is mandatory to have individual transformers for EXD-SH... and EXD-PM.
Parameter List
The document details a comprehensive list of parameters, including their codes, descriptions, available settings (Min, Max, Factory Setting), and specific functions related to control modes, refrigerant types, sensor types, valve types, alarms, and MOP (Maximum Operating Pressure) settings. This list is organized by circuit (Circuit 1 and Circuit 2) and includes detailed tables for parameter values and MOP default values for various refrigerants.
Display/Keypad Unit (LEDs and Button Functions)
The EXD-SH1/2 features a display with LEDs and buttons for operation and parameter setting. The display shows values for circuit 1 and circuit 2, indicating status like 'ON' (alarm) or 'OFF' (no alarm). Buttons include MENU, SET, and directional arrows (▲/▼) for navigation and parameter adjustment. Specific LED indicators show valve status (opening/closing) and regulation status.
Display Description
The upper display typically shows measured values like Superheat (K/F) or controlled temperature (°C/F), while the lower display shows Valve Opening (%) or Suction Pressure (bar/psig). The display can be switched between circuits for the EXD-SH2 using the 1/2 button.
Instant Value Display Mode
This mode allows real-time checking of measured/calculated values such as Superheat (SH), Valve Opening (OPEn), Suction Temperature (tASP), Suction Pressure (PEUA), and Saturation Temperature (tEuA).
Parameter Configuration Mode
Parameter configuration is protected by a numerical password (default '12'). Access involves pressing MENU and SET simultaneously for over 5 seconds. Users can navigate through parameters, adjust values, and save settings. Exiting without saving can be done by pressing SET and MENU or by a timeout.
Special Manual Functions (Reset, Clear)
These functions allow for factory resets (-Fdt) or clearing alarms (ALrr) by following a specific button sequence.
Manual Valve Operation (Service/Maintenance)
Valves can be operated manually by pressing SET for over 5 seconds. This allows for specific adjustments during service or maintenance. Parameters 1Ho and 2Ho control manual operation for circuits 1 and 2 respectively.
Error/Alarm Handling
The document provides a table detailing various error and alarm codes (e.g., 1E0/2E0 for pressure sensor error, AFE 1/2 for freeze protection, LSH 1/2 for low superheat, LOP 1/2 for low pressure, ACEr for Modbus timeout, PFA for power failure). For each alarm, it specifies the related parameter, alarm relay action, valve action, troubleshooting steps, and whether a manual reset is required.
Service/Troubleshooting
This section addresses common symptoms like incorrect superheat, unstable superheat, or valve issues. It provides potential causes and recommended actions, such as checking wiring, sensors, parameter settings, or valve size.
Upload/Download Key Function
The upload/download key allows for transferring configured parameters between identical systems for serial production. Procedures for both uploading (storing parameters to the key) and downloading (transferring parameters from the key to another controller) are described.