4-20mA & Modbus RTU Dewpoint Transmitter Instruction Manual Issue 2

EU Declaration of Conformity We Of Declare that Model Name: Shaw Moisture Meters Network House, 5 Lister Hill, Leeds LS18 5AZ, England AcuDew 2 wire, 4-20 mA loop powered transmitter Conforms to the following Directives: 2014/30/EU: The Electromagnetic Compatibility Directive and its amending Directives 2014/35/EU: The Low Voltage Directive and its amending Directives And has been designed and manufactured to the following standards: BS EN 61326-1:2013 Electrical Equipment for Measurement, Control and Laboratory use - EMC Requirements BS EN 61010-1:2010 Safety Requirements for Electrical Equipment...

UK Declaration of Conformity We Of Declare that Model Name: Shaw Moisture Meters Network House, 5 Lister Hill, Leeds LS18 5AZ, England AcuDew 2 wire, 4-20 mA loop powered transmitter. Conforms to the following Directives: 2014/30/EU: The Electromagnetic Compatibility Directive and its amending Directives 2014/35/EU: The Low Voltage Directive and its amending Directives And has been designed and manufactured to the following standards: BS EN 61326-1:2013 Electrical Equipment for Measurement, Control and Laboratory use - EMC Requirements BS EN 61010-1:2010 Safety Requirements for Electrical Equipment...

1.0 Unpacking Your Shaw Moisture Meters AcuDew Please examine the AcuDew package for any damage or mishandling. If any damage is evident please notify the carrier and the Shaw Moisture Meters representative from where this unit was purchased. You should have received (if ordered): ● 1 AcuDew 4-20 mA dewpoint transmitter ● 1 connecting cable of the length specified on your order or two metres as standard ● 1 instruction manual ● 1 pressure dewpoint circular calculator ● 1 small screwdriver If anything is missing please contact your distributor immediately. 1.1 General Description Shaw Moisture...

The mechanics of the AcuDew transmitter have been designed to cope with extreme environmental conditions. The rugged stainless steel and aluminium construction offers protection to IP66 NEMA 4X, with the transmitter electrical connections made via secure industrial type connector - M12 5 pin cable connector. The AcuDew transmitter can withstand 35,000kPa (350bar) maximum pressure and by employing low resistance cable, the transmitter can be located at significant distances, up to 1,000 metres (3,280 feet) from the data collection point. Designed with the operator in mind, for reliable and accurate...

Sulfur hexafluoride (SF6) has no effect on the sensor. If the gas has been exposed to arcing, however, it is possible that various acidic species will have been formed that will corrode the sensor. When testing SF6 that may have been arced, therefore, an acidity test should be carried out first; if the gas proves to be acidic then the moisture test should not be carried out. It is strongly recommended that the sample should not contain particulate matter, oil or other heavy hydrocarbon condensate. If these components contaminate the sample system and/or the measuring sensor, the system response...

2.2 Piping Installation Schematic MAIN PROCESS LINE Notes a. The sample pipe should be on the upper surface of the horizontal pipe or on a vertical section of pipe wherever possible. b. The sample tube should run continually upwards from the sample point. If this is not possible then an inspection port or drain tap should be installed at the lowest point in the system.

2.3 Piping Schematic Component Index Sample Isolation Valve - This is a recommended item as it allows access to the sample system without interrupting the main process line. 2. Filter Unit – A filter unit is recommended when the samples are likely to contain particulate matter. If the air/gas sample contains heavy hydrocarbon condensate, the filter must be of the coalescing type with a drain. The filter unit should be positioned as close to the sample point as practical. 3. Sample Tube – This should be stainless steel for dry air or gas applications but copper or carbon steel can be used where...

2.4 Installing and Commissioning The AcuDew dewpoint transmitter can be installed in three general ways: 1. Directly in to the process line. 2. As part of a sample conditioning system using a Shaw Moisture Meters sensor holder. 3. Using the AcuLoop display module with a sensor holder. Before installing the dewpoint transmitter, it is advisable to carry out an initial purge routine of the sample loop in order to remove the possibility of sensor damage on start-up. Refer to the sample system schematic in section 2.2. Open the inlet isolation valve slowly, until a small flow of air/gas at atmospheric...

3.1 AcuDew 4 - 20 mA Cable Assembly The cable assembly consists of a M12 5 pin cable connector used in conjunction with a 2 core 7/0.2 mm cable. Details of wiring can be found in Appendix D. 3.1.1 Connecting the AcuDew Cable Align the keyed groove in the connector with the keyed notch in the AcuDew, sesa>=c push inwards and screw the locking ring clockwise finger tight. To connect the AcuLoop display to the AcuDew: 1. Disconnect the connector from the AcuDew by turning the locking ring counter-clockwise. 2. Screw this connector on to the back connection of the AcuLoop display. 3. Align the keyed...

3.2 Wiring the AcuDew The AcuDew is a 2-wire, 4-20mA transmitter. For wiring and configuration to displays or logging devices please consult the device’s user manual. Typical electrical connection to generate a voltage output is shown below in Fig. 1 Analogue Output Connection. Note: the maximum value for Rs in this circuit can be calculated by the formula: Rs max = [40 x (Vs – 7)]Ω Pin 1 Pin 2 SENSE RESISTOR If the wiring resistance is expected to be more than a few percent of the value of Rs, then this resistance must be taken away from the answer to get the maximum usable value of Rs. Alternatively,...

Dewpoint transmitters with a Modbus RTU output can be connected to a Modbus Client device. This Client can be a gateway or any third-party Modbus RTU Client. The Modbus RTU link should be operated within the constraints below in order to ensure stable communications (please see Fig. 4 for details): • The maximum total bus length must not exceed 1,000 m. • The stub length to each node must not exceed 30 cm. To ensure a stable communication, a twisted-pair bus cable is strongly recommended (please see Fig. 4). • Bus cable specifications should follow the EIA485 Standard; shielded twisted pair is...