Teledyne 2000A-EU - General purpose thermal conductivity analyzer - Manual (Page 30)

Teledyne Analytical Instruments
3 Installation Model 2000A-EU
3-8
Zero: Floating input. A 5 to 24 V pulse input across the + and –
pins puts the analyzer into the
Zero mode. Either side may
be grounded at the source of the signal. A synchronous
signal must open and close the gas control valves appropri-
ately. See 3.3.3.6 Remote Probe Connector. (With the –C
option the internal valves operate automatically.)
Span: Floating input. A 5 to 24 V pulse input across the + and –
pins puts the analyzer into the
Span mode. Either side may
be grounded at the source of the signal. A synchronous
signal must open and close the gas control valves appropri-
ately. See 3.3.3.6 Remote Probe Connector. (With the –C
option, the internal valves operate automatically.)
Cal Contact: This relay contact is closed while analyzer is spanning
and/or zeroing. (See Remote Calibration Protocol below.)
Table 3-5: Remote Calibration Connections
Pin Function
9 + Remote Zero
11 – Remote Zero
10 + Remote Span
12 – Remote Span
40 Cal Contact
41 Cal Contact
Remote Calibration Protocol: To properly time the Digital Remote
Cal Inputs to the Model 2000A Analyzer, the customer's controller must
monitor the Cal Relay Contact.
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 close quickly.)
2) When the CRC closes, remove the zero command.