Campbell Scientific 0871LH1 Support Question
Campbell Scientific 0871LH1 Support Question
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Question posted by porojepajoohan on March 14th, 2016
Voltage Levels?
i am working with a 0871LH1. i have 3 voltage levels in discrete output . 1: ice:0.7 vdc , 2. de-icing:0.6 vdc and after 60 second 3. 0.5 vdc between blue and black wires using an oscilloscope. is it correct?
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Related Campbell Scientific 0871LH1 Manual Pages
0871LH1 Freezing Rain Sensor - Page 1
INSTRUCTION MANUAL
0871LH1 Freezing Rain Sensor
November 2012
Copyright © 2007 Campbell Scientific (Canada)Corp.
0871LH1 Freezing Rain Sensor - Page 4
... Figure 2 MSO Circuit Schematic ...3 Figure 3 Ice Detector...5 Figure 4 Mounting (part number 0871LH1 MNT)...6 Figure 5 General Hook-up Diagram ...8 Figure 6 Functional Block Diagram ...23
1 Discrete Outputs 10 10.3 CR1000 Example - Discrete Outputs 9 10.2 CR23X Example - RS422 Outputs 11
Appendix A: 1 RS-422 Output Format for RS422 Output 8 10 Program Examples...9 10.1 CR1000 Example...
0871LH1 Freezing Rain Sensor - Page 5
... axial movement of a pickup coil and an electronic comparator. The Rosemount Aerospace 0871LH1 Freezing Rain Sensor is used to indicate to sense ice formation again. The added mass of accreted ice causes the frequency of ice on the sensing probe.
These outputs are provided through an RS-422 interface and discrete outputs. This tube exhibits magnetostrictive properties: it expands...
0871LH1 Freezing Rain Sensor - Page 6
... Circuit Sectional View
Figure 2 MSO Circuit Schematic 3 In effect, the output stays on for 60 seconds after the beginning of the "last" icing encounter. The Status output indicates whether the freezing rain sensor is functioning correctly using tests that are described in more detail in an icing environment. rain sensor remains in following sections of this document...
0871LH1 Freezing Rain Sensor - Page 7
... VDC (sensing mode) 27W max at 24 VDC (deicing mode)
Temperature Operating: Storage:
-55°C to +71°C -65°C to +90°C
Communication Outputs
Discrete Outputs:
for Icing and Status No Icing - 0, Icing - 1 Status OK - 0, Status Failure - 1
Icing Signal Period:
60 second activation from start of icing measurement (Discrete or RS-422 outputs)
Connector Pinout
Table 1. 0871LH1...
0871LH1 Freezing Rain Sensor - Page 8
The maximum weight of a unit is an integrated unit containing both the sensor and processing electronics. Figure 3 Ice Detector 5 5 Physical Description
The freezing rain sensor is 318 grams (0.7lbs).
It contains a 7.35 cm (2.9") square faceplate for mounting to the 0871LH1MNT and a 7.28 cm (2.86") diameter housing containing the processing electronics.
0871LH1 Freezing Rain Sensor - Page 9
...cable ties. 5. The freezing rain sensor uses a power fail monitor to a sturdy ... proper drainage of melted ice. 3. NOTE: The sensor should exercise ...discrete output.
8 Mounting Considerations
Figure 4 Mounting (part number 0871LH1 MNT) The freezing rain sensor should be oriented into the prevailing wind. 4. Maintenance personnel should be mounted so as to be mounted to verify the supply voltage...
0871LH1 Freezing Rain Sensor - Page 10
... C2673 power supply. If you require the use of the RS422 output, then refer to section 9.2.
Table 3. If you require the use of the discrete outputs of the 0871LH1, then refer to section 9.1. All electrical connections and housings must be installed by a Certified Electrician.
9.1 0871LH1CBL-L Wiring for Discrete Output
Description Ice
Status RS422 A RS422 B Power Reference Case GND...
0871LH1 Freezing Rain Sensor - Page 12
...possible to ground. Table 6. Discrete Outputs
Monitor the discrete outputs of the 0871LH1, or the available RS422 output.
10.1 CR1000 Example - NOTE:
If the application requires the monitoring of the discrete outputs the 5Vdc connection must be configured as they may cause problems if shorted to collect icing information either by the discrete outputs of the 0871LH1 for the datalogger to...
0871LH1 Freezing Rain Sensor - Page 15
... Datalogger
'Declare Public Variables Public PTemp, batt_volt Public LH1_Byte_Count As Float Public Read_LH1 As Boolean Public Ice Public Ice_mm
'Define the Comport for the 0871LH1 here: Const LH1_comport = Com2
Public Variables from 0871LH1 Sensor via RS-422 Output Public LH1_Serial_Error As Boolean
'This is the decimal equivalent of Bytes 1 to Data Table(s)
'
as required...
0871LH1 Freezing Rain Sensor - Page 16
...(1,PTemp,FP2) Sample (1,Ice,IEEE4) Sample (1,Ice_mm,IEEE4) EndTable
'This Subroutine Sets all values to a Defaut Error State if Serial Communications do not work Sub LH1_Error_State LH1_Probe_Heater_State = "... = NAN LH1_CHECKSUM = NAN EndSub
0871LH1_GetData Subroutine (Typically Takes 3 Seconds to execute Use an MD485 configured to RS-485, RS-232 Transparent Mode. 9600 BAUD for RS...
0871LH1 Freezing Rain Sensor - Page 18
...Probe Heater State If (LH1_Byte(1) AND &B00000100) 0 Then LH1_Probe_Heater_State = "On" Else LH1_Probe_Heater_State = "Off" EndIf
'0871LH1 Bytes 2 and 3 are MSO Frequency count 'Calculate Frequency from the count as follows LH1_MSO_Frequency = 774060000/((LH1_Byte(2) 'BIT 1 - Ice Output If (LH1_Byte(1) AND &B00000010) 0 Then LH1_Ice_Output = "Ice" Else LH1_Ice_Output = "No Ice" EndIf
'BIT 2 -
0871LH1 Freezing Rain Sensor - Page 19
...) = &B10000000 Then LH1_ERR_PROBE_HEATER = "Always Off" ElseIf (LH1_Byte(5) AND &B011000000) = &B11000000 Then LH1_ERR_PROBE_HEATER = "On" EndIf
If (LH1_Byte(5) AND &B001000000) 0 Then LH1_ERR_DE_ICING = "FAIL" Else LH1_ERR_DE_ICING = "OK" EndIf
'0871LH1 output ON time in 10 Minute Increments LH1_ON_Time_Days = ((LH1_Byte(6)
0871LH1 Freezing Rain Sensor - Page 20
... through a passive voltage divider and voltage comparator.
17 Whenever a failure is detected and verified, the freezing rain sensor stops detecting and annunciating icing conditions and the heaters are verified by delaying (debouncing) the failure for a period of the heater is monitored.
• The ICE discrete output is in the correct state. Appendix A
1 RS-422 Output Format for non...
0871LH1 Freezing Rain Sensor - Page 21
... when the heater is de-icing correctly. Frequencies between 39000 and 40150 Hz are valid.
• The probe heater is ON and a de-icing failure has been detected. BIT Information.
If the frequency indicates that the ice has been removed within 25 seconds. (De-Icing Fail).
5 BIT Failure That Disables Ice Output
The Ice output is enunciated, the software...
0871LH1 Freezing Rain Sensor - Page 22
... heater is turned on the discrete outputs so monitoring electronics or test equipment can test the freezing rain sensor functionality by squeezing the tip of the probe between the Ice signal (blue wire in control port) and the power reference ground (black wire in G terminal). Initiated BIT will quickly heat the probe to the datalogger use a digital voltmeter (DVM);
0871LH1 Freezing Rain Sensor - Page 27
... interruptions of RAM, and 32 input/output ports. 1.1 Microcontroller
The freezing rain sensor uses an Intel 87C51-type microcontroller to sense and detect ice. The microcontroller runs at a nominal ... less. The watchdog indicates impending power loss so the ice detector can be determined whether the heater is the electronic control portion of an unintended heater ON condition. Each ...
0871LH1 Freezing Rain Sensor - Page 28
... 60 seconds. Internal circuitry converts the 24 VDC input power to prevent stray high-voltage from coupling into the unit and damaging the output transistor. The ice output has feedback to the microcontroller for software to verify it is transient protected to meet RTCA DO-160C lightning requirements and to 5 VDC for use by 130 Hz while the Ice...
0871LH1 Freezing Rain Sensor - Page 29
...correctly. 0871LH1 model uses this feedback to verify that the ice output is 10.1 KΩ. To interface to the 0871LH1...Software
DO-178B used as a guideline
26 Test Procedure
Power Input
DO-160C:
Cat Z, 18 - 29.5 VDC
Voltage Spike
DO-... Level 3
Multiple Stroke:
Waveform 3: Level 3
Temperature Variation
DO-160C:
Cat A
Temperature/Altitude
DO-160C:
Cat D2 (-55°C to the Ice Signal...
0871LH1 Freezing Rain Sensor - Page 30
... RS-422 Spec
Per RS-422 Spec
Ice
F
Output
Ground Active (1.5V Max)
0.5 - 50 mA
Open Inactive
Status
G
Output Ground Inactive (1.5V Max)
0.5 - 50 mA
Open Active
**Ice will be correctly detected between these voltages. Proper probe de-icing, however, is only guaranteed when input voltage is 24VDC or greater.
Wire Gauge
20
20 20 20-24 20-24...