Integrating HART Sensors with the Campbell CR1000 Datalogger

Transcription

1 5 Gould Road, PO Box 2155 New London, NH USA Voice: (603) Integrating HART Sensors with the Campbell CR1000 Datalogger Sensor Application Note #29 Revision 01/30/2018 Overview The HART Communication Protocol (Highway Addressable Remote Transducer) is a hybrid analog+digital industrial automation protocol. Its most notable advantage is that it can communicate over legacy 4 20 ma analog instrumentation current loops, sharing the pair of wires used by the analog only host systems. According to Emerson,[1] due to the huge installed base of 4 20 ma systems throughout the world, the HART Protocol is one of the most popular industrial protocols today. HART protocol has made a good transition protocol for users who wished to use the legacy 4 20 ma signals, but wanted to implement a "smart" protocol. The protocol was developed by Rosemount Inc., built off the Bell 202 early communications standard in the mid-1980s as a proprietary digital communication protocol for their smart field instruments. Soon it evolved into HART and in 1986 it was made an open protocol. Since then, the capabilities of the protocol have been enhanced by successive revisions to the specification. ( Interfacing The Campbell loggers do not natively support HART Protocol, either in hardware or software. This Sensor Application Note will outline use of the ICP-DAS i-7570 Serial to HART Converter for the hardware interface. Point-to-Point and Multi-Drop HART is supported, sensors may be powered via loop power or external power. Contact Canary Systems to obtain the I-7570 Serial to HART Converter. Note: The Gage Types outlined later in this Sensor Application Note are included in the current release of MultiLogger Suite. If the Gage Types are not present as shown then your software must be updated. Software updates are available from the Support area of our website at Integrating HART Sensors with the Campbell CR1000 Datalogger 1

2 System Wiring and Configuration Physical connections are shown below. The following table outlines the typical wiring connections: Connection COM1 COM2 COM3 COM4 RS-232 Description RS-232 RXD C1 C3 C5 C7 Pin 3 Datalogger/Computer Connection RS-232 TXD C2 C4 C6 C8 Pin 2 Datalogger/Computer Connection RS-232 GND G G G G Pin 5 Datalogger/Computer Connection HART+ See following wiring diagrams HART- See following wiring diagrams +VS 12V 12V 12V 12V 12v Datalogger Power (12V) GND G G G G G Datalogger GND Note: This Sensor Application Note will not cover use of the i-7570 for RS-422/485 applications. Integrating HART Sensors with the Campbell CR1000 Datalogger 2

3 Two wiring configurations are shown, for loop powered applications and external power applications. The i-7570 is equipped with an internal loop termination resistor, by default it is connected. See the i-7570 Users Guide for instructions on disabling the internal loop termination resistor if required. The wiring below is typical for a loop powered transmitter. Note that the actual supply used will vary depending on the requirements of the transmitter. The wiring below is typical for transmitters with an external power connection. Note that the actual supply used will vary depending on the requirements of the transmitter. Integrating HART Sensors with the Campbell CR1000 Datalogger 3

4 Using HC_Tool to Test the Sensor Software from ICP DAS must be used for testing and configuring the HART sensors. The HC_TOOL software is available from ICP DAS via the following link: ftp://ftp.icpdas.com/pub/cd/fieldbus_cd/hart/converter/i-7570/software/ Once downloaded it must be uncompressed from the.rar file, decompression utilities are available from several download sites. Launch the software by clicking on the HC_Tool executable. If the default COM port (in this example COM1) is correct then press Open, otherwise the proper COM port must be selected. The Settings form displays the currently selected COM port, as well as other serial communication settings. Leave all settings with the exception of Port Name as their default. Use the Port Name drop-down to select the proper COM port. Press OK when finished and return to the main screen. Integrating HART Sensors with the Campbell CR1000 Datalogger 4

5 Now click Open to Open the COM port. Any errors opening the port will display an error message and the Start button will NOT be enabled. Usually this is due to an incorrect COM port selection or another device using the port. Next click Start to being a search for devices. Addresses will start at 0 and continue even after finding a device. Integrating HART Sensors with the Campbell CR1000 Datalogger 5

6 Once a device is found then click Stop to stop the auto-polling process. An example is shown at right of a sensor found with Polling Address 0 (default). Next select the HTCfg menu option to display the HART Command form. This allows sending various polling commands and viewing the responses. By default the Cmd1 tab is selected, next press Start to display the Primary Variable result. Integrating HART Sensors with the Campbell CR1000 Datalogger 6

7 To view the actual sent and received responses click on the Data Log tab from the main menu. The most important setting is the Polling Address. For MultiLogger programming to work the device must be set to Address 0. Select the Cmd6 tab to display the Write Polling Address form. If the address of the device is not 0 then configure 0 in the dropdown and press Start. The updated Polling Address will be sent to the device, a dialog will display to confirm the new setting. Press OK to return to the HART Command form. Close HC_Tool by clicking in the upper right of the main form. Integrating HART Sensors with the Campbell CR1000 Datalogger 7

8 MultiLogger Configuration To configure MultiLogger first select the datalogger node to be configured in the Network Manager and click Logger (or double-click the node). This displays the Logger form. Select the Program tab, then click Direct Connect. Integrating HART Sensors with the Campbell CR1000 Datalogger 8

9 The Configure Direct Connect Channels form will display. To configure the HART sensor select Digital HART as Gage Type and Make, then select the appropriate COM port and variable to retrieve. Primary and Secondary Variables may be selected. What these values represent depends on the sensor. Configure any additional Conversions or Units Conversions as needed. When configuration is complete press Accept to return to the Logger form. Configure the Single Interval, then press Update. Integrating HART Sensors with the Campbell CR1000 Datalogger 9

10 The logger memory will be cleared, press Yes to continue. MAKE SURE PRIOR DATA WAS COLLECTED. Then the program will be sent to the datalogger. After successful program update the Text Monitor mode will start. Note the updated value in the configured Direct Connect channel. Note, if there is a error in configuration or wiring the sensor will return an error code. Use the HC_Tool software to confirm correct function of the interface and wiring. Integrating HART Sensors with the Campbell CR1000 Datalogger 10