EDR Fault Bitmap Mode

Overview

Normally the EDR reads a run status register and fault code register and expects some number (or enumeration) that symbolizes the state and fault code(s). The fault number represents the first-out fault.

On many PLC panels faults are not reported as a first-out code, but instead the faults are reported in a bitmap where each bit represents an active fault. As an example, register 40001 bit 0 might be "Low suction" and Register 40001 bit 1 might be "high suction". In this case both could be active or inactive at the same time.

The second type is not as common, but it is supported by the EDR if set up correctly.

Using Bitmap Mode

To support bitmap fault codes there is a checkbox on the EDR alert setup page labeled "Run and Shutdown Register Use Bitmap". Check this box and select "Save" to start using this mode.

The Run and fault code registers do not have to be the same register but both do have to be using bitmaps. Usually both will be the same register.

Note that on the PLC all registers have to be in a row, so only the first register is entered in the setup. For example, if the shutdown code register is set up as ID 10 and register 40001 but the shutdown code table goes up to 40 items the EDR will read 40001, 40002, and 40003 to make sure all 40 items are covered (since one modbus register can cover 16 items)

For the Run Status table enter a value for each bit position and whether to interpret the unit as running, faulted, or in-between when a "1" appears in that bit position. Usually all the bits signify a fault so the table will show 0=faulted, 1=faulted, 2=faulted, etc. If some bits are unused they might be set as in-between.

For the Fault code table enter a value for each bit position and what the shutdown in that position corresponds to.

Example

A PLC provides this bitmap:

• 40001.0 Low suction
• 40001.1 High suction
• 40002.3 Low Discharge

In this case, bits 0, 1, and 19 are used (Since 40002 is 16 bits offset, and 16+3 = 19). The run status table will be set up as:

• 0 = faulted
• 1 = faulted
• 19 = faulted

The fault code table will be set up as:

• 0 = Low suction
• 1 = High suction
• 19 = Low discharge

If there is a low suction shutdown the PLC will report a "1" in register 40001 and "0" in 40002. The EDR will see that bit [0] is set, and will interpret this as faulted, and position 0 label will be called out as "Low Suction".

WiFi Value

The "Value" showing under the run status and fault code registers will provide the first bit position that is set with a 1-offset. This can be a bit confusing since the tables start at position 0. In the above example the value will report "0" when running, "1" for low suction, "2" for high suction, "20" for low discharge. If multiple bits are faulted only the lowest will be represented in the value.