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C4 Manual Rev 7.5.2
Some errors, especially those unique to the C4, are only defined in the
Error/Status String. In the event of one of these errors, bit 1 of the Error Byte
(this bit was not used by the CC-3) is set to indicate an extended error. The
Status Byte and SRQ are thus set as well.
The Error/Status String is a bit mapped 64 byte string (512 bits) that contains
both “event triggered” and “status monitoring” information. A complete
description of the Error/Status String and it’s behavior can be found in Section
7.8.3.
3.10 Fail-safe System
The C4 is designed to sense the loss of control circuit power due to opening of a
safety limit switch such as those supplied with all Sigma chambers and thermal
platforms. If the controller is in the RUN mode and the fail-safe is tripped, the
controller will stop controlling and display fl safe on the digital LED
display. It will also report the fail-safe tripped condition over the computer bus
interface if in use. In order to re- establish normal operation, the failsafe system
on Sigma chambers and thermal platforms requires that power be cycled off then
on in addition to the out of range temperature condition subsiding. Use the rotary
Mode Switch on the controller front panel. Turn the switch to OFF to clear the
fail-safe condition.
If the controller is to be used independently of a Sigma Systems temperature
chamber or thermal platform, connect pins 10 & 11 of the 12-pin power plug to pin
3 for 120 volt operation. In the case of 208-240 volt operation connect pins 10 &
11 to pin 6 through a 56kS ½ watt resistor. Opening this connection will cause
the above described failsafe condition.