Sigma C4 manual General Description

1.2 General Description

Using the model C4, temperature control is available manually from the front panel, by use of user entered programs, or via remote control via either a EIA-232 or IEEE-488 GPIB. The controller has a precision temperature reading capability with a digital read-out. Two temperature probes can be connected to the controller allowing either probe or both probes to be the control probe(s) while either probe can be used to take measurements.

Two additional controlled device ports are available. They are intended for on/off control of a refrigeration compressor and an external load such as a device under test, or a main chamber or platform power relay. These ports normally are supplied as TTL level (low voltage) ports but are optionally available with solid state relays to control line voltage as in the case of units with mechanical refrigeration. The compressor control port may be toggled from the front panel at any time in the manual (LOCAL) mode. The compressor is designed to not cycle on and off with the temperature control function.

The controller operates in each of four modes:

Local	Single Setpoint control from the front panel. Simple
Mode	Start/Stop functionality.
	Programmed control using programs entered, stored, and
Program	run from the front panel. 100 Temperature/Duration
Mode	Program steps available. Multiple programs may be stored
	and called as needed.
	Control via EIA-232 or IEEE-488 GPIB. The IEEE-488
	interface implementation is a TALKER/LISTENER with
Remote	serial poll. Extended addressing and parallel poll
Mode	capabilities are not supported. The EIA-232 interface is
	fully configurable for baud rate, data bits, stop bits and
	parity.
Setup	Used to define and store operation and environment
Mode	variables that control how the C-4 behaves.

10 C4 Manual Rev 7.5.2