GREYSTONE PMRMC Series Room Particulate Matter Transmitter User Manual

GREYSTONE PMRMC Series Room Particulate Matter Transmitter

INTRODUCTION

The Particulate Matter Transmitter uses an optical sensor based on laser scattering principles and features innovative contamination resistance technology to perform highly accurate and reliable PM measurements. With a continuous-operation lifetime of more than 8 years, the sensor will provide long-term reliability and high-resolution particle size binning for the detection of environmental dust and other particles. The sensor is housed within an attractive, low-profile enclosure to monitor ambient PM levels for room applications. The sensor achieves excellent performance characteristics, including high accuracy and low power consumption to ensure stable long-term operation. The PMRMC features both 4-20 mA and voltage outputs (0-5 / 0-10 Vdc) for simple integration into any building automation system to assure good indoor air quality. The device is also available with an RS-485 MS/TP network connection including either Modbus or BACnet® protocol.

BEFORE INSTALLATION

Read these installation instructions carefully before commissioning the PM Sensor. Failure to follow these instructions may result in product damage. Do not use in an explosive or hazardous environment, with combustible or flammable gases, as safety or emergency stop devices or in any other application where the failure of the product could result in personal injury. Use electrostatic discharge precautions during installation and do not exceed the device ratings.

MOUNTING
The particulate matter transmitter mounts directly on a wall or onto an electrical wall box and should be mounted to a wall box five feet from the floor. Do not mount the sensor near doors, opening windows, supply air diffusers, or other known air disturbances. Avoid areas where the sensor is exposed to vibrations or rapid temperature changes. The cover is hooked to the base at the top edge and must be removed from the bottom edge first. Use a small Phillips screwdriver to loosen the security screw as shown in Figure 1. (Complete removal of the screw is not required). Use a screwdriver to carefully pry each bottom corner if necessary tip the cover away from the base as shown in Figure 2 and sit it aside. The PCB must be removed from the base to access the mounting holes. Follow usual anti-static procedures when handling the PCB. The PCB is removed by pressing the enclosure base to unsnap the latch near the bottom edge, then the PCB can be lifted out of the base as shown in Figure 3. Set the PCB aside until the base is mounted on the wall. For added protection, place the PCB in the supplied anti-static bag. Mount the base by screwing to an electrical box or directly to the wall as shown in Figure 4. The mounting hole locations are shown in the Dimension drawings. After the base is mounted

using the appropriate holes, remove the PCB from the anti-static bag and feed the wires through the center hole of the PCB. Place the top of the PCB into the latches on the top of the backplate and gently snap the bottom edge of the PCB into place as shown in Figure 4. Make wire connections as per the Wiring Illustrations on Page 2 and install a decorative cover by placing the top of the cover into the cover holder on the top of the backplate and snapping the bottom into place as shown in Figure 4. Tighten the security screw with a screwdriver.

WIRING
The particulate matter sensor has standard screw block connectors and easy wire access to facilitate wiring. It is recommended that shielded twisted pair wiring at least 22 AWG be used for all connections and that the device wires not be run in the same conduit with wiring used to supply inductive loads such as motors. Disconnect the power supply before making any connections to prevent electrical shock or equipment damage. Make all connections in accordance with national and local electrical codes. The device power (24 Vac/dc) is connected to the terminal marked PWR (POWER). This terminal is used for the positive dc voltage or the hot side of the ac voltage. The device is reverse voltage protected and as such will not operate if connected backward. The common of power supply is connected to the terminal marked COM (COMMON). Note that this device has a half-wave type power supply which means the power supply common is the same as the output signal common. Therefore, several devices may be connected to one power supply and the output signals all share the same signal common. Use caution when grounding the secondary of an ac transformer or when wiring multiple devices to ensure that the circuit ground point is the same on all devices and the controller. In general, the transformer should not be connected to earth ground when using devices with an RS-485 network connection.

The analog output signal is available on the OUT (OUTPUT) terminal. This signal is jumper selectable for either voltage or 4-20 mA output signal type. See Figure 5. The voltage output signal defaults to 0-5 Vdc but may be changed to 0-10 Vdc via the menu. These options are clearly indicated on the device PCB. The analog output signal is typically connected directly to the Building Automation System (B.A.S.) and used as a control parameter or for logging purposes. Check the controller Analog Input type to determine the correct connection and signal type before applying power. The device generates the analog output signal (sourcing) and must not be connected to a powered input or device damage may occur.
For voltage type output signal the device has a minimum load that it is able to drive, similarly for current type output signal the device has a maximum load that it is able to drive with a particular power supply voltage. Observe and follow these ratings in the Specification section or inaccurate reading may result. The 4-20 mA output signal can easily be converted to a 1-5 Vdc signal for controllers accepting this type of input. Simply insert a 250 ohm (0.1% is best) resistor between the “+” and “-” inputs of the controller. This will convert the 4-20 mA signal to the desired 1-5 Vdc. See Figure 6.

If the device includes the optional network connection, use twisted shielded pair to connect to the terminals marked A-, B+ and SHLD (SHIELD). The positive wire connects to B+, the negative to A- and the cable shield must be connected to the SHLD terminal on each device. The shield wire should be connected to the earth ground at one end of the network only. See Figure 7. If the device is installed at either end of an RS-485 network, an end-of-line (EOL) termination resistor (121 ohms) should be installed in parallel with the A- and B+ terminals. This device includes a network termination resistor and jumper that can be used to connect the EOL resistor on the PCB. Simply move the jumper to the EOL position and no external resistor is required. See Figure 8.

A network segment is a single shielded wire loop run between several devices (nodes) in a daisy chain configuration. The total segment length should be less than 1220 meters (4000 feet) and the maximum number of nodes on one segment length is 64. Nodes are any device connected to the loop and include controllers but do not include the EOL terminators. To install more than 64 devices, or to increase network length, repeaters will be required for proper communication. The maximum daisy chain length (segment) depends on transmission speed (baud rate), wire size and a number of nodes. If communication is slow or unreliable, it may be necessary to wire two daisy chains to the controller with a repeater for each segment. An optional signal is the alarm relay output available on the NO (NORMALLY OPEN), NC (NORMALLY CLOSED ) and R.COM (RELAY COMMON) terminals. The R.COM terminal is not connected to the power supply COM terminal, the relay output is completely isolated. The relay contacts may be connected to a controller Digital Input (DI) for status monitoring or used to directly control an alarm or ventilation fan. Do not exceed the device contact ratings. In some cases a separate control relay may be used between the particulate matter sensor relay and a large fan for example. See Figure 9.

OPERATION – START-UP

After applying power to the device, it will enter the start-up mode and the LCD will indicate the software version number, the PM range, the PM alarm setpoint (if applicable) and the analog output type for two seconds each.

If the network option is installed, then the start-up sequence will also show the network protocol, the baud rate, and the device address. Then the device will start normal operation and display the PM concentration value.

OPERATION – NORMAL
During normal mode, the device reads the PM sensor and calculates the Air Quality Index based on a 24-hour time average. The real-time PM concentration value is displayed on the LCD and set as the output value for the analog output. The output value is updated once per second. The LCD may be configured via the menu to display either the PM value or the AQI. If the optional tri- color LED is installed, it will change color to indicate Good (Green), Moderate (Yellow) or Poor (Red) air quality. On start-up when the first readings are obtained, the Air Quality reading for the device averages the concentration level as necessary until the required time base setting is reached. For example, if only 10 readings are available then the output value is calculated as the average of those 10 readings. The next output value will be an average of 11 readings. This short averaging will continue until the unit has been running for 24 hours. Once 24 hours is reached then the AQI value will always be the average of readings over the past 24 hours. The device also monitors the keypad and takes appropriate menu actions for setup. The network version of the product allows for the configuration of settings via BACnet® or Modbus protocol and the BACnet® objects or Modbus registers are updated with the appropriate values and alarm conditions are monitored.
OPERATION – ALARM
All models except for the analog output only without relay will have a PM setpoint alarm. The alarm will control the optional relay or network variables as applicable to the model. The PM alarm setpoint, hysteresis and time delay may be configured via the menu or network. The details of each setting and operation is explained in the Setup Menu section.

OPERATION – SETUP MENU

The Setup Menu has several items as shown below. To enter the menu, press and release the key while in normal operation. This will enter the Setup Menu step 1, pressing the key second-time advances to step 2. Each press of the key saves the selection and advances the menu item. The key is used to make changes to program variables by scrolling through the available options. If the SetupMenu is not active for 5 minutes (no key press), then the menu will exit and the device returns to normal operation.

< MENU>
Press and hold to enter the setup menu. Once in menu release