Homer Error Byte

As part of each block of measured data (Measurement Data Object MDO), the Homer sends an Error Byte, where various error conditions and warnings are encoded in a bitwise manner. In Homer Communication Protocol the byte is designated HER (Homer Error Byte). The byte can be decoded and error conditions can be announced (e.g., through LED-like indicators and messages in Results windows). The Maxi Results window displays the Homer Error Byte value explicitly both in decimal and binary form.

The Error Byte is included in the data to be saved or logged (see How to Save Measured Results and Data Logging). This enables offline validity check of the saved results.

Bits of the Error Byte, if set to 1, signify the following conditions (bit #0 is LSB):

Bit	Weight	Type	Meaning
0	1	Error	Pulsed mode measurement error occurred
1	2	Error	A/D converter overflow in at least one of the four detector channels
2	4	Error	Internal temperature too low (below the calibration interval)
3	8	Error	Internal temperature too high (above the calibration interval)
4	16	Warning	Low Signal: signal level too low to ensure accurate data
5	32	Warning	Substitute frequency sent
6	64	Error	Measurement data are (for any reason) invalid
7	128	Reserved

The value of the Error Byte is the sum of the weights of the individual bits that are set to 1.

Example

Suppose the following conditions occur:

• A/D converter overflow (bit #1, W1=2)

• Internal temperature too high (bit #3, W3=8)

• Substitute frequency sent (bit #5, W5=32)

Then

Error Byte = W1 + W3 + W5 = 2 + 8 + 32 = 042 = 00101010 bin

Low Signal Warning

Low Signal condition occurs when the measured incident power falls below a predefined threshold. The threshold in watts is defined in the Hom.cfg configuration file by the line

LowPowLvl_W=100;       Incident power threshold for "Low Signal" condition

The Low Signal flag can be used:

• Internally in Homer Autotuner.

• In HomSoft.

Low Signal Use in Homer Autotuner

In Autotuner, the Low Signal condition can suspend autotuning (e.g., chaotic tuning when microwave power drops). The default power-up behavior is defined by the line

WaitRF=TRUE

in the Tun.cfg configuration file. When set to TRUE, autotuning is suspended as long as Low Signal condition persists.

HomSoft can override this default by its own setting – see the System Info window, page Autotune, item Wait if RF power is low. When set to YES, autotuning is suspended as long as the Low Signal condition persists.

Setting NO may sometimes be useful (noise-based chaotic tuning without microwave power can be used for motors testing purposes).

Low Signal Use in HomSoft

When the Low Signal condition occurs, the displaying of the received results can either continue (showing random, noisy data), or can be suspended, depending on the status of Homer|More|Suspend on Low Signal menu iem. Updating of the traces is then halted until the condition ceases.