SRS Labs CTC100, User Manual

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Introduction 9
CTC100 Programmable Temperature Controller
Each output has two voltage ranges (50 V and 20 V) and three current ranges (2A, 0.6A, and
0.2A). Each output also has an auto-range setting that continuously adjusts the current and voltage
ranges to the smallest values needed to reach
g.
The 0.6A and 0.2A current ranges offer lower noise levels than the 2A range and are intended to
be used when more precise control is needed. On the other hand, the 20V range is only included
for safety reasons and it has essentially the same performance as the 50V range.
The maximum power that each output can deliver depends on the resistance of the heater as
shown below.
Maximum output power as a function of output range and heater resistance
The heater outputs are generated by two printed circuit boards (PCBs). If the temperature of
either PCB exceeds 60°C, the CTC100 automatically shuts off the corresponding output. This is
likely to occur if the heater resistance is under 10 , if the ambient temperature outside the chassis
is above 30°C, and/or if the system fan is turned off or not working. The PCB temperatures can be
monitored by going to the System Setup screen and setting the Monitors control to Show.
Hardw are faults
The CTC100 can detect certain unsafe operating conditions. If such a condition occurs and
persists for more than 2 seconds, the CTC -enable it, disable and
then re-enable all outputs by pressing the Output Enable key three times). In addition, one of the
following error messages appears in a pop-up window on the CTC100
Measured heater current differs from desired value -
zero, and the current flowing out of the positive terminal differs from the desired current by
more than 0.25A. This error can occur if the CTC100 is out of calibration. It can also mean
that the CTC100 has been damaged and is no longer capable of correctly regulating its
output current or of producing its rated output current.
Current at + and heater terminals is different -zero,
and the he same as the current
flowing into the negative terminal. This error can occur if one of the leads is shorted to an
external ground.
Output is off but heater current was detected
but current is flowing into the negative terminal. This error may indicate that the heater is
shorted to a power source other than the CTC100. It can also indicate a failure of the
output circuit.