Call Us 800.362.8774 Call Us 866-294-5847 Contact Training Training Training WeatherTRAK Login WaterCompass Login AppManager Login

Knowledgebase

    Baseline Controller Platform Communication Solutions 2-Wire Troubleshooting

    Resolving Many Two-Wire No Response Messages

    PDF

    Table of Contents

    Summary IMPORTANT: Tools Required Process Steps Check the Messages Check the Controller Check the Two-Wire Path What Our mA Measurement Means Determining Number of Devices Device mA Draw Two-wire mA Draw Example

    Summary

    In the event of multiple device no replies, where a multitude of device message are present over a large section of two-wire, read what's below for added information and resolution steps.

    IMPORTANT: Tools Required

    #2 Phillip screwdriver

    Wire stripper

    Approved mA clamp meter such as: Armada Pro 95i, Tempo 360B

    Not all mA clamp meters have the required resolution to find the mA load discrepancy on the wire path. Approved mA clamp meters have low pass filter settings that provide a stable mA reading while devices are communicating over the two-wire, microamp resolution and a true RMS measurement.

    Baseline Message Example

    Process Steps

    Check the Messages

    Check the message list for specific device information. Device messages with wording like "No reply," "No response," or "Two-wire communication failure" indicate a problem with two-wire communication. You can see the device ID at the bottom of the error screen. Messages can help determine if the issue is isolated to one section of wire path. 

    Check the Controller

    3200 Info Screen
    1. Disconnect the two-wire path from the controller then power cycle the controller. 
    2. Verify there is voltage on the two-wire terminals. Approximately 34VAC.

    Legacy 3200 Only: If there is no voltage measured on the two-wire terminals, check if the two-wire status is OFF. If OFF, navigate to Advanced via the dial, then to the two-wire settings menu. Two-wire always on should be set to YES. 

    1. Check the two-wire mA draw from the Run screen on your controller. mA higher than expected indicate a ground fault or a two-wire device that needs to be replaced. 
    3200S Zone Tile View

    Check the Two-Wire Path

    Before starting, identify your wire path configuration. If the wire path is looped, disconnect the furthest loop from the controller. If the wire path is a star or straight run, proceed to step 1.

    1. Confirm the expected mA draw for the wire path or section of wire path you are testing. This can be done by summing the mA draw of each two-wire device downstream of your measurement location. Enter the device quantities from where you're taking your clamp measurement to the end of your wire path into the Two-wire Device mA Draw Reference and Calculator.

    Note: If you do not know the number of devices downstream of your mA measurement location, trace your wire path from the measurement location to the end of the wire path, opening each valve box and accounting for all of the inbound wire pairs. You can then use the Device mA Draw Calculator to get your expected mA draw.

    (Two-wire device mA draw)(device quantity) = Expected mA draw

    1. Confirm that the mA draw on the red and black wires match. With your milliamp clamp meter, clamp the red wire and record the mA value. Do the same for the black wire. 

    Note: When measuring mA with your clamp meter, it is important to have the wire in the center of the clamp meter (Alignment markers may be present) and perpendicular to the meter.

    1. Compare the expected mA draw to the actual mA draw measured with your clamp meter at your measurement location.  

    Note: This should be done when system is idle. mA draw while the system is watering will be higher due to running solenoids.

    1. Work your way from the controller down the wire path, or use the binary search method, using the clamp meter to determine where the problem is. Once the problem is identified, replace splice(s) or two-wire device(s) as necessary. For mA measurements lower than expected, use the Device mA Draw Calculator linked above (or table below) to see how many devices could still be connected between the wire path problem and the controller. Target that location on your wire path first.

    Note: As you work your way down the two-wire, the expected mA draw will change as the current measured is for downstream devices only. Please see Two-wire mA Draw Example at the bottom of the page. Branch 1 indicates a small mA leak at the end of the wire path, causing our actual reading to be ~1mA higher than our expected reading. 

    What Our mA Measurement Means

    mA draw measured on both wires is higher than the mA draw expected
    • This problem is almost always in a valve box (i.e two-wire device). The problem will be found where the high mA value drops to the expected mA value. 
    • Two-wire devices pulling higher than expected current (greater than 30% over expected) should be replaced.
    • A higher than expected mA draw only measurable on the downstream wire going to a downstream valve box, and the upstream wire in that downstream valve box, indicates a ground fault buried between the valve boxes.
    mA measured on both wires is lower than the mA summed, or expected
    • This means a disconnection at one or more locations on the wire path. The problem will be found where the expected mA value drops near or to zero.
    • Use Device mA Draw table to see how many two-wire devices can be summed to match your mA measurement. This gives you a starting location to inspect your wire path. 
    • Connections at the last reading of expected mA should be inspected and re-done. 
    • Two-wire devices measuring lower than expected current can be recovered if you can cut back to clean wire. If corrosion is found too close to the two-wire device, it should be replaced.
    mA readings higher or lower than expected on one of the wires on our two-wire path
    • Indicates a problem on that wire. 
    • An above expected mA reading most likely indicates a leak to ground on that wire. Use your clamp meter to find where the higher than expected mA draw drops to expected.
    • A higher than expected mA draw only measurable on the downstream wire going to a downstream valve box, and the upstream wire in that downstream valve box, indicates a ground fault buried between the valve boxes.
    • A below expected reading indicates corroded wire, wire damage or disconnected two-wire devices (Via wire damage or bad splices). Use the Device mA draw table to see how many devices could still be connected between the wire path problem and the controller. Target that location on your wire path first.

    For more information see Interpreting Current Readings.

    Determining Number of Devices

    1. Collect the controller program summary locally via USB export or remotely via AdminManager.

    Note: The program summary file does not include unassigned two-wire devices. It is important that all devices on the two-wire path be assigned for properly determining expected mA draw on the two-wire. 

    Device mA Draw

    *Measured with the Armada Pro 95i

    Two-wire device mA Draw (Controller Two-wire Terminals)
    BL-5201/01MV/02/04 Station BiCoder 0.6
    BL-5201DC/01-MV DC Station BiCoder 2.1
    BL-5201PR Pump Start BiCoder 1.1
    BL-5303 Air Temperature Sensor 5.5
    BL-5308/09 Flow BiCoder 9.5
    BL-5311/15 Moisture Sensor 2.6
    BL-5401 Coach's Button 2.8
    BL-5402 Event Switch BiCoder 1.8
    BL-5406-KIT Pressure Sensor and BiCoder Combo 12.2 @ 0 psi / 28.8 @ 150 psi
    BL-5407-KIT Precipitation Sensor and BiCoder Combo 9.5
    BL-LA01 Lightning/Surge Arrestor 0.04
    BL-PFS Plastic Flow Sensor 5.7

     

    Two-wire mA Draw Example

    Readings in red indicate actual mA draw on the two-wire

    If you check all of the preceding steps and fail to resolve the issue, consider contacting Hydropoint Support. Hydropoint Support can be reached at support@baselinesystems.com, support@hydropoint.com or 866-294-5847. 

    Related Articles