Measuring mode
The terminal supports 4 measuring modes. The measuring mode is selected via the Mode entries in the process data (control word) or in CoE 0x80n0:0D. The measuring mode determines the time of the measurement and the wire connection.
- 0: 4-wire measurement
- 1: 4-wire measurement (single-shot mode)
- 2: 2-wire measurement
- 3: 2-wire measurement (single-shot mode)
 | Measurements Measurements cannot take place simultaneously on both channels. 4-wire connection is recommended for the EL3692. |
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Operating mode |
Mode entry |
Principle of operation |
|---|---|---|
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Alternating mode |
Both channels measuring mode "0" or "2" |
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|
Single shot mode |
Both channels measuring mode "1" or "3" |
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Mixed mode |
One channel measuring mode "0" or "2", the other channel mode "1" or "3" |
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Table 1: Operating modes
Alternating mode
This mode is the delivery state of the terminal. Both channels alternately measure a resistance at their connection points. The measurement is indicated by the lit status LED.
Single shot mode
Each channel only measures on request by the application. A rising edge in the "Start Conversion" bit in the control word triggers a measurement. If both channels are triggered simultaneously, the channels are processed sequentially. The first channel has priority.
This mode is suitable for measurements during which heating of the test specimen due to repeated measurements is undesirable.
Mixed mode
One channel measures continuously, the other only on request. This mode is a combination of the two previous modes. Once channel measures continuously and interrupts its measurement only if a measurement is requested on the other channel.
This mode is suitable for measuring high-resistance test specimens. Constant current flow (provided the other channel is never activated) means that all charging processes are complete. A delay after CoE 0x80n0:31 is therefore not required.
In single-channel mode measurement of the second channel can be triggered by writing 1 or 3 in the entry 0x80n0:0D (mode).
Broken wire
The only way in which the EL3692 can detect a "broken wire" is therefore by registering sustained exceedance of the measuring range ("Overrange").
In 4-wire mode, there may be combinations of wire breakage that may not result in an unambiguous "Overrange" error and can only be detected based on sustained measured value variations in an implausible range.