Series 3700A Switch and Control Cards Reference Manual
Section 13: Model 3750 multifunction control card
3700AS-909-01 Rev. A / Preliminary
13-11
Using the card when configured as voltage outputs
To set the analog voltage output level to -3.5 volts:
channel.setmode('1010', channel.MODE_VOLTAGE_1)
channel.setoutputenable('1010', channel.ON)
channel.write('1010', -3.5)
Once the output voltage is set and the output is enabled, the output attempts to drive the external
circuitry to the value specified. If the output voltage attempts to deliver more than the specified
overload current, a fault condition exists.
To determine whether the output is in a fault condition:
circuit_fault = channel.getstate('1010', channel.IND_OVERLOAD)
If this returned value is true, then the output is either currently in a fault condition or was in a fault
condition in the past if the fault state is latched. See
(on page 13-19) for more
information.
If auto protect mode is enabled, the output relay disconnects after approximately one second of
sensing a persistent fault condition. This output disable removes any overload current-related fault
condition. We strongly recommend that the voltage output is used in auto protect mode. When
enabled, this mode prevents the output from experiencing prolonged stresses during some fault
conditions. These stresses can cause potentially long thermal recovery times after the fault has been
cleared.
To use the output in auto protect mode:
channel.setmode('1010', channel.MODE_PROTECT_VOLTAGE_1)
Using the card when configured as current outputs
To set a current output to 10mA:
channel.setmode('1010', channel.MODE_CURRENT_1)
channel.setoutputenable('1010', channel.ON)
channel.write('1010', 10e-3)
Once the output current is set and the output is enabled, the output attempts to drive the external
circuitry to the value specified. If the output current drives a load that causes the output voltage to
exceed the specified compliance voltage, a fault condition exists.
To determine whether the output is in a fault condition:
circuit_fault = channel.getstate('1010', channel.IND_OVERLOAD)
If this returned value is true, then the output is either currently in a fault condition or was in a fault
condition in the past if the fault state is latched. See
(on page 13-19) for more
information.
If auto protect mode is enabled, the output relay disconnects after approximately one second of
sensing a persistent fault condition. This output disable removes any overload current-related fault
condition. We strongly recommended that you use the current output in auto protect mode. When
enabled, this mode prevents the output from experiencing prolonged stresses during some fault
conditions. These stresses can cause potentially long thermal recovery times after the fault has been
cleared.
To use the output in auto protect mode:
channel.setmode('1010', channel.MODE_PROTECT_CURRENT_1)