General Resistance Thermocouple Simulators (ETS/TSC) are versatile laboratory instruments that provide high precision and stability in compact portable units.
They are designed and constructed as to be essentially independent of the ambient temperature and loading within their ratings.
Each has the following basic functional modules:
1. A chopper-stability operational Amplifier
2. A highly stable reference source.
3. A Kelvin-Varley potential divider.
4. A cold junction compensator (CJC) for each of 5 separate thermocouple systems.
5. Connection facilities for any thermocouple type.
These precision instruments are not to be confused with low-cost hand-held “do-everything” devices. The TSC/ ETS line of T/C Simulators provides “standards lab performance.” TSC/ETS units provide ±1/4% accuracy and can be used to calibrate virtually any T/C system at any temperature with internal cold function compensation referenced to 0°C. Potentiometers and ice baths are not required.
These GR instruments, moreover, provide “zero output impedance,” an exclusive feature available with no other simulator. “Zero output Z” insures that the system element (readout device, scanner or whatever) under test or calibration will respond only to the simulated temperature signal supplied by the General Resistance TSC or ETS. This eliminates the need to disconnect the system thermocouple.
In addition to its TSC/ETS line of ultra-precision instruments, General Resistance offers its Model E-35B Instant Lab for use as a T/C simulator. Model E-35B is unmatched for multi-usage versatility. It performs as a thermocouple and RTD simulator, current/voltage source and resistance decade box ... all with ±0.1% accuracy.
(See Table I and back cover for further details on E-35B.)
— The finest and most versatile instrument of its type available anywhere outside of a primary standards laboratory. Designed for use as a portable standard and as a constant voltage/current source as well as thermocouple simulator.
— Similar to the TSC-47UR
with 6 rather than 7 decade KVD. See Table I Specifications for specific differences between these two models.
— Same accuracy and “Zero output Z” performance as TSC Series relative to T/C simulation. Differs from TSC units in that it is truly portable with internal batteries. It also provides built-in run-up pot, control circuit and temperature measurement capability. Does not offer 10V F.S. Voltage Source
Model E-35B —see back page.
These instruments simulate all thermocouple types —E, J, K, R, S, T, B, N, etc. —internally referenced-junction -compensated to 0°C. Connection to the thermocouple system to be tested is through the use of specially designed THERMOCLIPS1* (see Table II). Output is dialed in voltage on thumbwheel-decade switches. Any reference tables can be used — DIN, NBS, etc.
BATTERY OPERATION (ETS-15
Instrument will operate for approximately 8 hours on a full charge under normal conditions and recharge within 10 hours. Units are fully operative during the charge cycle. Trickle charging takes place as long as unit is plugged in, whether it is turned ON or OFF.
Five basic operating modes are as follows:
1. Thermocouple simulation with zero output impedance.
Appropriate Thermoclips (See Table II) are clipped into the system. Since output impedance is “zero” there is no need to disrupt system wiring. After temperature-equivalent voltage is dialed, this known signal is used to calibrate or troubleshoot scanners, linearizers or readouts.
2. Thermocouple simulation with output impedance established by front panel “run-up" pot.
(AVAILABLE WITH MODEL ETS-15
ONLY.) Built-in runup pot is set to the system Impedance. Thermoclips are used to substitute the simulated output for the active thermocouple. The “run-up” pot is used to simulate the system’s wiring in order to calibrate loop-impedance-dependent analog readout devices.
3. Temperature measurements. The Simulator is connected to the active measuring thermocouple with the appropriate Thermoclips. The thumbwheel switches are adjusted until a null Is indicated on a built-in meter which is designed for logarithmic response. (External null detector required for Models TSC-46
4. Control mode. (AVAILABLE WITH MODEL ETS-15
ONLY.) Appropriate Thermoclips are connected. Any voltage differences between that set on the Simulator dials and that produced by the system thermocouple is detected and amplified by a fixed gain of 25. This "error signal” appears at the CONTROL terminals and provides external control circuitry with the analog information required to correct temperature, activate alarms, etc.
5. High accuracy voltage/current source.
(AVAILABLE WITH MODELS TSC-46
ONLY.) These sophisticated instruments provide all of the precision performance characteristics of GR's time-tested DAS voltage/current sources in addition to serving as thermocouple simulators.