Teledyne 3020T operating instructions Zero

3 Installation Model 3020T

ZERO:	Floating input. 5 to 24 V input across the + and – terminals
	puts the analyzer into the Zero mode. Either side may be
	grounded at the source of the signal. 0 to 1 volt across the
	terminals allows Zero mode to terminate when done. A
	synchronous signal must open and close the external zero
	valve appropriately. See 3.3.9 Remote Sensor and Solenoid
	Valves. (With the –C option, the internal valves automatically
	operate synchronously.)
SPAN:	Floating input. 5 to 24 V input across the + and – terminals
	puts the analyzer into the Span mode. Either side may be
	grounded at the source of the signal. 0 to 1 volt across the
	terminals allows Span mode to terminate when done. A
	synchronous signal must open and close the external span
	valve appropriately. See 3.3.9 Remote Sensor and Solenoid
	Valves. (With the –C option, the internal valves automatically
	operate synchronously.)

Cal Contact: This relay contact is closed while analyzer is spanning and/or zeroing. (See Remote Calibration Protocol below.)

Remote Calibration Protocol: To properly time the Digital Remote Cal Inputs to the Model 3020T Analyzer, the customer's controller must monitor the CAL CONTACT relay.

When the contact is OPEN, the analyzer is analyzing, the Remote Cal Inputs are being polled, and a zero or span command can be sent.

When the contact is CLOSED, the analyzer is already calibrating. It will ignore your request to calibrate, and it will not remember that request.

Once a zero or span command is sent, and acknowledged (contact closes), release it. If the command is continued until after the zero or span is complete, the calibration will repeat and the Cal Relay Contact (CRC) will close again.

For example:

1)Test the CRC. When the CRC is open, Send a zero command until the CRC closes (The CRC will quickly close.)

2)When the CRC closes, remove the zero command.

3)When CRC opens again, send a span command until the CRC closes. (The CRC will quickly close.)

4)When the CRC closes, remove the span command.

When CRC opens again, zero and span are done, and the sample is being analyzed.

3-8 Teledyne Analytical Instruments