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. 

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. 

IMPORTANT: Correct 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.

Process Steps

Before starting it is important that you identify the wire path configuration and if it is a looped wire path you break any looped points on the wire path.

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. (Refer to Device mA Draw table below)

Note: If you do not know the number of devices downstream of your milliamp measurement location, please look for additional details

2. 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.

3. 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.

4. 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 problem is identified, replace splice(s) or two-wire device(s) as necessary.

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 measurements mean:

• mA measured on both wires is higher than the mA summed, or 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 average) should be replaced.
• 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. Connections at the last reading of expected mA should be replaced. 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, while the other reads the expected value, indicates a problem on that wire. An above expected mA reading most likely indicates a leak to ground on that wire, while a below expected reading indicates corroded wire, wire damage or disconnected two-wire devices (Via wire damage or bad splices). 

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 mA Draw Example

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.