The Model 340 includes a graphic LCD with fluorescent backlight display that is fully configurable and can display up to eight readings.
This shows a variation of the display with a large loop 1 heater output graphic bar where the PID parameters are not displayed, but the heater output is more prominent.
The user can display 1 to 8 readings from any of the available inputs. The units available are the sensor units of mV, V, W, kW, nF, or temperature units of °C or K. Results of the math feature can also be selected.
The user can select the sensor type, and the controller will automatically select the sensor units, excitation, and range. If ‘special’ type is selected, the user can choose any available excitation and input range.
Additional Inputs Available For Model 340
The following optional inputs are available for the Model 340. Only one can be installed at a time, and the standard inputs stay in the instrument and remain fully functional. Calibration for the option is stored on the card so it can be installed in the field without recalibration.
3462 Dual Standard Input Option Card
Adds two standard inputs to the Model 340, appearing on the display as C and D. The card has separate A/Ds and excitation for each sensor. A microprocessor on the card manages the A/D and communication with the Model 340. Allows the Model 340 to read four sensors and use any of them as a control sensor.
3464 Dual Thermocouple Input Option Card
Adds two new thermocouple inputs to the Model 340, appearing on the display as C and D. The card has separate A/Ds and excitation for each sensor. A microprocessor on the card manages the A/D and communication with the Model 340. Thermocouple inputs range from cryogenic temperature to 1000 °C, with built-in room temperature compensation. Curves for thermocouple types E, K, and AuFe 0.07% vs. Cr are included. The user can add other types.
3465 Single Capacitance Input Option Card
Adds a new capacitance input to the Model 340, appearing on the display as C. The card has separate A/D and excitation for the sensor. A microprocessor on the card manages the A/D and communication with the Model 340. The 3465 is intended to control temperature in strong magnetic fields using a Lake Shore Model CS-501 capacitance temperature sensor.
3468 Eight Channel Input Option Card
Adds eight sensor inputs to the Model 340. The optional inputs are broken into two groups of four and appear on the display as C1–C4 for Input C, D1–D4 for Input D. The 3468 includes two A/D converters, one for each group of four inputs, and individual excitation for each sensor. Each input group must use the same sensor type, but the two groups can be different. The multiplexed inputs provide new readings for all eight inputs twice each second. The 3468 inputs are not recommended for temperature control because the reading rate is too slow to allow good stability.
A variety of sensor types are supported by the Model 3468, but not as many as the standard inputs. Diode and platinum configurations have similar specifications to the standard inputs, reduced only slightly to account for multiplexing. However, the NTC RTD configuration is quite different than the standard inputs. The option has a limited resistance range of 7.5 kΩ with a fixed current excitation of 10 µA. This limitation significantly reduces the low temperature range of the inputs. The option also does not support current reversal to reduce the effect of thermal EMF voltages. The original standard inputs remain fully functional allowing the Model 340 to measure 10 sensors when the option is installed.