User manual

Series 3700 System Switch/Multimeter Reference Manual Section 13: Instrument Control Library (ICL)
3700S-901-01 Rev. C / July 2008 13-131
dmm.connect
Usage
To read the DMM relay connection setting:
value = dmm.connect
value: Represents the present DMM relay connection setting
To write the DMM relay connection setting:
dmm.connect = value
value: Represents the desired DMM relay connection setting
where value is:
dmm.CONNECT_NONE or 0 to have no relays connected
dmm.CONNECT_ALL or 7 to have all relays connected (default value)
dmm.CONNECT_TWO_WIRE or 1 to have 2-wire relay connected
dmm.CONNECT_FOUR_WIRE or 3 to have 2-wire & sense relays connected
dmm.CONNECT_TWO_WIRE_AMPS or 5 to 2-wire & amps relay connected
dmm.CONNECT_AMPS or 4 to have amps relay connected
Remarks
Use the value setting, as indicated in the usage section to indicate, which of the DMM
relays you want connected to the backplane. The relays are bitmapped into the lower
3 bits of the value where bit 0, a value of 1, represents the 2-wire relay. Bit 1, a value
of 2, represents the sense relay and bit 3, a value of 4, represents the amp relay. By
setting the appropriate bit to a 1, then that relay is closed. Likewise, setting it to zero,
opens that relay.
An error will be generated only if the sense relay bit is set to a 1 and if the sense relay
with amps is selected. These two settings correspond to a value of 2 or 6, respectively.
Also, an error will be generated for a value less than 0 or greater than 7.
Default setting is dmm.CONNECT_ ALL.
Details
Use of this command is not recommended with the exception of special cases. The
default setting should handle most applications.
Example
To connect the DMM 2-wire and amp relays to the analog backplane:
dmm.connect = dmm.CONNECT_TWO_WIRE_AMPS
dmm.dbreference
Attribute
Indicates the DB reference setting for the DMM in volts.
Usage
To read the DB reference:
value = dmm.dbreference
value: Represents the present DB reference setting in volts
To write the DB reference:
dmm.dbreference = value
value: Represents the desired DB reference in volts (1e-7 to 1000)