application note # 108
APPLICATION NOTE # 108 WATERLOG H-4161 MODULE CONFIGURATION FOR 4 TO 20 MA OUTPUT
Purpose Detail the commands required to configure a WaterLog H-4161 module to monitor communications between a datalogger and an SDI sensor output so that the H-4161 module can set a 4 to 20 mA current proportional to the chosen SDI sensor reading . Description The WaterLog H-4161 module sets a 4 to 20 mA current which is proportional to a detected SDI sensor value. The H-4161 must be connected on the same SDI bus as the sensor whose reading is being used to set the 4 to 20 mA output. The H-4161 module is powered from the SDI bus; however, the module does require an external supply to provide power for the 4 to 20 mA loop. Equipment FTS Quick Touch series Datalogger Datalogger battery cable 12 V, absorbed glass mat, deep cycle battery WaterLog H-4161 module
FTS Forest Technology Systems Ltd.
- 1 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108 Electrical Connection The following diagram and picture show the module wiring connections required for the H4161 module.
MONITORED SENSOR
H2 DATALOGGER A
USB DEVICE
TELEMETRY
SDI BUS
USB
H-4161 MODULE
RAIN
SDI A
SDI C
SOLAR PANEL
GROUND
SDI B
SDI D
BATTERY
AMMETER + 12VDC BATTERY
-
I 4 to 20mA Current Loop
H-4161 Wiring Diagram and Picture
FTS Forest Technology Systems Ltd.
- 2 of 7 -
700-AN-108 rev 2
4-20mA+ 4-20mA -
GND GND AUX DATA DATA + 12V
B
APPLICATION NOTE # 108
H-4161 Configuration The H-4161 module must be properly configured to capture the appropriate sensor reading and configure to scale the captured reading to the 4-20 mA output. The steps required are given below. Refer to the H-4161 owner’s manual for the module details (FTS number 701-H-4161-Manual). 1/
Connect the H-4161 module to an FTS dataloggers SDI port
The H-4161 module receives power from the SDI bus and can be configured without the 4 to 20 mA loop section connected. 2/
Assign the H-4161 module a unique SDI address
Although data is not being read directly from the H-4161 module, the module still requires a unique SDI address. 3/
Set H-4161 module to Monitor Mode
Use the datalogger’s SDI transparent mode to place the H-4161 module in ‘monitor mode’ by issuing the aXWMM0! command. Note: a is the H-4161 module’s SDI address 4/
In the H-4161 module, set the SDI address of the sensor to be monitored
Use the datalogger’s SDI transparent mode to set the SDI address of the sensor to be monitored in the H-4161 by issuing the aXWMAn! command. Note: a is the H-4161 module’s SDI address n is the monitored sensor’s SDI address 5/
In the H-4161 module, set the parameter number of the sensor to be monitored
Use the datalogger’s SDI transparent mode to set the parameter of the sensor to be monitored in the H-4161 by issuing the aXWMPp! command. Note: a is the H-4161 module’s SDI address p is the monitored sensor’s parameter number (1 to 9) The H-4161 module does not care which M command the datalogger sends to the sensor as the H-4161 module just looks for appropriate D command parameter number. Eg:
The DTS-12 returns seven parameters in response to an aM2! command. Parameter number 3 is Median Turbidity and parameter number 7 is Water Temperature.
FTS Forest Technology Systems Ltd.
- 3 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108
6/
In the H-4161 module, set the sensor reading value which corresponds to the low (Min) 4 mA output
Use the datalogger’s SDI transparent mode to set the captured sensor value (Min) which corresponds to 4 mA loop current by issuing the aXWILd! command. Note: a is the H-4161 module’s SDI address d is the monitored sensor’s parameter value All sensor values below the low set value (Min) will cause the H-4161 to set 4 mA loop current. 7/
In the H-4161 module, set the sensor reading value which corresponds to the high (Max) 20 mA output
Use the datalogger’s SDI transparent mode to set the captured sensor value (Max) which corresponds to 20 mA loop current by issuing the aXWIHd! command. Note: a is the H-4161 module’s SDI address d is the monitored sensor’s parameter value All sensor values above the high set value (Max) will cause the H-4161 to set 20 mA loop current. 8/
The H-4161 module configuration process is complete.
H-4161 Test and Operation The H-4161 module can be checked to see if the correct sensor value is being captured by issuing the appropriate M command followed by D commands to the monitored sensor (i.e. aD0!, aD1!, etc - until all parameters have been read) and then watching the H-4161 front panel. Everytime the H-4161 module captures a value from the SDI bus the spinner in the upper right corner of the module’s display will rotate by 1/8th of a revolution. The module’s front panel should display the captured value as well as the calculated output loop current (note that the captured value is always displayed with units of ft). The loop current calculated from the captured value can be verified with the following formula:
Iout = 4 mA + { 16 * (SDI – Min) / (Max – Min) } Where: Iout is the calculated loop current setpoint (as shown on the module’s display)
SDI is the sensor value captured by the H-4161 module (as shown on the module’s display)
MIN is the sensor value set as the 4 mA output (step 6) MAX is the sensor value set as the 20 mA output (step 7) Note that if the current loop is broken and then reconnected after the H-4161 module has set a loop current, the loop current will return to 4 mA until the next value is captured. FTS Forest Technology Systems Ltd.
- 4 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108 To check the 4 to 20 mA loop, insert an ammeter into the 4 to 20 mA loop. The external power supply must be present to power the loop. The loop current can be explicitly set by the H-4161 module using the aXSMc! command. Note: a is the H-4161 module’s SDI address c is the 4 to 20 mA loop value (4.0 to 20.0) Note that a value captured from the SDI bus will over-ride the value set by the aXSMc! command.
FTS Forest Technology Systems Ltd.
- 5 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108 Contact Information If you have any questions or would like further information please contact FTS. CONTACT: FTS FOREST TECHNOLOGY SYSTEMS, LTD. 1065 Henry Eng Place Victoria, B.C. V9B 6B2 PH: FAX:
(250) 478-5561 (250) 478-8579
or or
1-800-548-4264 1-800-905-7004
ON THE INTERNET: Web Page:
www.ftsinc.com
E-mail:
[email protected]
Technical Support:
[email protected]
FTS Forest Technology Systems Ltd.
- 6 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108
Revision History Revision
Date
Description
1
2010-Mar-11
Original release
2
2010-Mar-16
Clarify Iout calculation formula
FTS Forest Technology Systems Ltd.
- 7 of 7 -
700-AN-108 rev 2
Purpose Detail the commands required to configure a WaterLog H-4161 module to monitor communications between a datalogger and an SDI sensor output so that the H-4161 module can set a 4 to 20 mA current proportional to the chosen SDI sensor reading . Description The WaterLog H-4161 module sets a 4 to 20 mA current which is proportional to a detected SDI sensor value. The H-4161 must be connected on the same SDI bus as the sensor whose reading is being used to set the 4 to 20 mA output. The H-4161 module is powered from the SDI bus; however, the module does require an external supply to provide power for the 4 to 20 mA loop. Equipment FTS Quick Touch series Datalogger Datalogger battery cable 12 V, absorbed glass mat, deep cycle battery WaterLog H-4161 module
FTS Forest Technology Systems Ltd.
- 1 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108 Electrical Connection The following diagram and picture show the module wiring connections required for the H4161 module.
MONITORED SENSOR
H2 DATALOGGER A
USB DEVICE
TELEMETRY
SDI BUS
USB
H-4161 MODULE
RAIN
SDI A
SDI C
SOLAR PANEL
GROUND
SDI B
SDI D
BATTERY
AMMETER + 12VDC BATTERY
-
I 4 to 20mA Current Loop
H-4161 Wiring Diagram and Picture
FTS Forest Technology Systems Ltd.
- 2 of 7 -
700-AN-108 rev 2
4-20mA+ 4-20mA -
GND GND AUX DATA DATA + 12V
B
APPLICATION NOTE # 108
H-4161 Configuration The H-4161 module must be properly configured to capture the appropriate sensor reading and configure to scale the captured reading to the 4-20 mA output. The steps required are given below. Refer to the H-4161 owner’s manual for the module details (FTS number 701-H-4161-Manual). 1/
Connect the H-4161 module to an FTS dataloggers SDI port
The H-4161 module receives power from the SDI bus and can be configured without the 4 to 20 mA loop section connected. 2/
Assign the H-4161 module a unique SDI address
Although data is not being read directly from the H-4161 module, the module still requires a unique SDI address. 3/
Set H-4161 module to Monitor Mode
Use the datalogger’s SDI transparent mode to place the H-4161 module in ‘monitor mode’ by issuing the aXWMM0! command. Note: a is the H-4161 module’s SDI address 4/
In the H-4161 module, set the SDI address of the sensor to be monitored
Use the datalogger’s SDI transparent mode to set the SDI address of the sensor to be monitored in the H-4161 by issuing the aXWMAn! command. Note: a is the H-4161 module’s SDI address n is the monitored sensor’s SDI address 5/
In the H-4161 module, set the parameter number of the sensor to be monitored
Use the datalogger’s SDI transparent mode to set the parameter of the sensor to be monitored in the H-4161 by issuing the aXWMPp! command. Note: a is the H-4161 module’s SDI address p is the monitored sensor’s parameter number (1 to 9) The H-4161 module does not care which M command the datalogger sends to the sensor as the H-4161 module just looks for appropriate D command parameter number. Eg:
The DTS-12 returns seven parameters in response to an aM2! command. Parameter number 3 is Median Turbidity and parameter number 7 is Water Temperature.
FTS Forest Technology Systems Ltd.
- 3 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108
6/
In the H-4161 module, set the sensor reading value which corresponds to the low (Min) 4 mA output
Use the datalogger’s SDI transparent mode to set the captured sensor value (Min) which corresponds to 4 mA loop current by issuing the aXWILd! command. Note: a is the H-4161 module’s SDI address d is the monitored sensor’s parameter value All sensor values below the low set value (Min) will cause the H-4161 to set 4 mA loop current. 7/
In the H-4161 module, set the sensor reading value which corresponds to the high (Max) 20 mA output
Use the datalogger’s SDI transparent mode to set the captured sensor value (Max) which corresponds to 20 mA loop current by issuing the aXWIHd! command. Note: a is the H-4161 module’s SDI address d is the monitored sensor’s parameter value All sensor values above the high set value (Max) will cause the H-4161 to set 20 mA loop current. 8/
The H-4161 module configuration process is complete.
H-4161 Test and Operation The H-4161 module can be checked to see if the correct sensor value is being captured by issuing the appropriate M command followed by D commands to the monitored sensor (i.e. aD0!, aD1!, etc - until all parameters have been read) and then watching the H-4161 front panel. Everytime the H-4161 module captures a value from the SDI bus the spinner in the upper right corner of the module’s display will rotate by 1/8th of a revolution. The module’s front panel should display the captured value as well as the calculated output loop current (note that the captured value is always displayed with units of ft). The loop current calculated from the captured value can be verified with the following formula:
Iout = 4 mA + { 16 * (SDI – Min) / (Max – Min) } Where: Iout is the calculated loop current setpoint (as shown on the module’s display)
SDI is the sensor value captured by the H-4161 module (as shown on the module’s display)
MIN is the sensor value set as the 4 mA output (step 6) MAX is the sensor value set as the 20 mA output (step 7) Note that if the current loop is broken and then reconnected after the H-4161 module has set a loop current, the loop current will return to 4 mA until the next value is captured. FTS Forest Technology Systems Ltd.
- 4 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108 To check the 4 to 20 mA loop, insert an ammeter into the 4 to 20 mA loop. The external power supply must be present to power the loop. The loop current can be explicitly set by the H-4161 module using the aXSMc! command. Note: a is the H-4161 module’s SDI address c is the 4 to 20 mA loop value (4.0 to 20.0) Note that a value captured from the SDI bus will over-ride the value set by the aXSMc! command.
FTS Forest Technology Systems Ltd.
- 5 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108 Contact Information If you have any questions or would like further information please contact FTS. CONTACT: FTS FOREST TECHNOLOGY SYSTEMS, LTD. 1065 Henry Eng Place Victoria, B.C. V9B 6B2 PH: FAX:
(250) 478-5561 (250) 478-8579
or or
1-800-548-4264 1-800-905-7004
ON THE INTERNET: Web Page:
www.ftsinc.com
E-mail:
[email protected]
Technical Support:
[email protected]
FTS Forest Technology Systems Ltd.
- 6 of 7 -
700-AN-108 rev 2
APPLICATION NOTE # 108
Revision History Revision
Date
Description
1
2010-Mar-11
Original release
2
2010-Mar-16
Clarify Iout calculation formula
FTS Forest Technology Systems Ltd.
- 7 of 7 -
700-AN-108 rev 2
