Product overview Vaisala CARBOCAPâ Carbon Dioxide and Temperature Transmitter GMW87M is a wall-mount transmitter designed to fulfill the needs for CO measurements in demanding conditions (for example, dusty or humid installation locations). GMW87M can be accessed with the Modbus RTU protocol over an RS-485 interface. The communication settings for the protocol are entered with DIP switches on the GMW87M component board.
Electrostatic Discharge (ESD) can cause immediate or latent damage to electronic circuits. Avoid touching exposed component contacts during installation and maintenance. Regulatory compliances Vaisala GMW80 series transmitters are in conformity with the provisions of the following EU directives: • RoHS Directive • EMC Directive The conformity is declared with using the following standards: •...
Installation The GMW87 transmitter is designed to be installed on a mounting box or directly to a wall surface. For transmitter dimensions, see Figure 3 (page Figure 2 Mounting GMW87M Cable gland for leading the input/output cable (Ø 4 ... 8 mm) inside the enclosure Alternative lead-through for wiring through the back (break seal and transfer cable gland to the threads on this lead-through) Wiring instructions label...
6. Push down gently on the GM10 module. The module should be straight and firmly connected. 7. Tighten the cable gland and close the transmitter cover (4 screws). CAUTION! Mounting bases are tailored to the individual transmitter at the factory. If you attach several mounting bases before connecting the transmitters, store the transmitters in their original shipping boxes, so that you can match the serial number on the mounting base to the serial number on the shipping box.
Modbus communication The Modbus variant used in GMW87M is Modbus RTU. For a list of the Modbus registers available in GMW87M, see Modbus registers (page 10). You can use up to 8 transmitters on the same RS-485 line. You must configure each transmitter on the line to have a different Modbus address.
• Check that the GM10 module is properly attached • Contact Vaisala for a replacement GM10 module If you cannot locate the source of the error and return the transmitter to operational state, contact Vaisala technical support. See Technical support (page 15).
Modbus reference Function codes Table 2 Modbus function codes Function code (decimal) Function code (hexadecimal) Name Read Holding Registers 43/14 / 0E Read Device Identification Data encoding In the data registers, the numeric values are available in one or two formats with separate register addresses: 32-bit IEEE floating point format and/or 16-bit signed integer format.
Register Address Register description Data Notes number format 0200 Device status 16-bit 0000 : Status OK; if other values integer are returned, see Troubleshooting (page 0201 Error code 32-bit Used by Vaisala Technical Support integer when solving device problems M212445EN-A...
Table 7 Device identification objects Object ID Object ID Object name Example contents (hexadecimal) VendorName “Vaisala” ProductCode "GMW80" MajorMinorVersion Software version (for example, "1.4.0") VendorUrl “https://www.vaisala.com/” ProductName "Vaisala CARBOCAP(R) Carbon Dioxide Transmitter GMW80" Transmitter serial number, e.g. SerialNumber "J1140501" Vaisala-specific device information object.
Modbus communication example Reading CO concentration value The device address used in the following example is 240 (F0 ). The values returned by the device differ depending on the ambient conditions. Your device might not return exactly the same values. Request Response Bytes on the line...
±(15 ppm + 2 % of reading) over five years Warm-up time 10 min for full specification Response time (63 %) 7 min Carbon dioxide sensor Vaisala CARBOCAPâ GM10 Product lifetime > 15 years Table 9 Operating environment Property Specification Operating temperature 0 …...
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Property Specification Digital output (RS-485) Isolated, supports Modbus RTU protocol • Modbus RTU address range: • 1 … 247 (up to 255 possible, non-standard) • Bit rates: • 4800, 9600, 19200, 38400, 57600, 76800, 115200 • Parity: • None or Even •...
Please see the applicable supply contract or Conditions of Sale for details of the warranty for each product. Technical support Contact Vaisala technical support at helpdesk@vaisala.com. Provide at least the following supporting information as applicable: • Product name, model, and serial number •...