MGR10 A/B/C - Revision : I (for 7.0 software revision)
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6.2.2.5 Multiwire Interface Messages (ATN True)
Data transferred on the DIO lines while the controller asserts the ATN line (low) are bus management
commands and device addressing information. This is known as Command Mode.
GTL Go
To
Local
This causes the addressed listener to return to local panel control (exit the REMOTE state). The
device will return to remote when REN is sent again.
SDC Selective Device Clear
This causes the addressed listener to reset to a device-dependent state. This is the same as DCL
(Device Clear) but only affects the addressed device.
PPC Parallel
Poll
Configure
Parallel Poll is not implemented. This command is ignored.
GET Group Execute Trigger
This causes all devices which have the GET capability and are currently addressed to listen to
initiate a pre-programmed action (e.g. trigger, take a sweep etc.). Some devices may also
recognise a device-dependent data character or string for this function (equivalent but requires
entry into Data Mode).
Sending either GET or *TRG will make the microhmmeter perform the INITiate command and
take a measurement. The command must be sent as a single message. Sending either GET or
*TRG within a command string will result in a ‘command error’ and the trigger will be ignored.
TCT Take
Control
This instructs the addressed device to become the bus controller. The microhmmeter is not
capable of this function. The command is ignored.
LLO Local
Lockout
This disables return-to-local control (push button) on devices that recognise the command.
Recognising devices accept the command whether they are addressed or not. REN must be set
false to re-enable the push button, this also replaces all devices under local control. The
microhmmeter does not have a manual "local" button, so this command is equivalent to the
single-wire REN function.
DCL Device
Clear
This command causes all recognising devices to return to a pre-defined device-dependent state.
Recognising devices respond whether they are addressed or not.
The effect of DCL is as follows:
- The parser is reset to await a new command.
- The output queue is flushed.
- The instrument is put into the Operation Complete Command Idle State and
the Operation Complete Query Idle State.
