Super Systems AC20 User Manual

Page 54

When the checking will be successful, these conditions no
longer exist and the automatic Probe test will be immediately
performed.
The timer programmed to perform the next Probe test will start
only at the end of the previous Probe test.
If the Probe test is requested by keys and it cannot be started,
the following information is displayed for 2 seconds:
Upper display: Prob
Middle display:inh
Lower display: Number of the first not complied condition (1 up to

5 previously described).

During the Probe test, the instrument will operate as follows:
1) it shows

on the upper display: Prob
on the middle display:tESt

2) It connects a 47.5 K

Ω

shunt across the probe terminals and

waits for 15 seconds in order to stabilize the measure.

3) It calculates the probe resistance Rp by applying the following

formula:

Rp (in K

Ω) =

(Ec/Es - 1) • 47.5

where:

Ec is the sensor output (in mV) measured before the shunt

connection.

PROBE TEST PROCEDURE

(Available only if “O2” is not selected as primary control
variable)

The Probe test may be carried out:
- manually (by pressing TST + FUNC keys), or
- from serial link, or
- automatically, after a period (set by the "Pb.tr" [R.H04]

parameter) started from the end of the previous Probe test.

The Probe test cannot be carried out if:
1) the first part of the SMART algorithm (TUNE) is in progress;
2) five minutes are not elapsed from instrument power on or from

the end of another procedure (Burn off, Purge or Probe test);

3) The probe temperature is less than 1000 °F (538 °C) or in

error condition.
Note

Note

Note: the temperature value will not be taken into account if
mV is the selected controlled variable and "t.t.Ac" parameter
[C.I07] is equal to "nO".

4) the probe output is less than 1000 mV;
5) the probe output is unstable (drift more than 10 mV/minute).
If one or more conditions previously described still exist the
automatic Probe test will be frozen, the state of these conditions
are checked by the instrument every minute.
During this time, the instrument operates as previously set before
the Burn off request.