ABB Z-MT Commissioning And Calibration Procedures page 20

4.6C Analogue Retransmission Output(s) – Fig. 4.2C
Connect the milliammeter in place of the retransmission output to be calibrated, i.e. terminals '1' and '2' for 'O/P MODULE 1',
'O/P MODULE 2' or 'O/P MODULE 3'.
Connect the millivolt source in place of the 'PROBE T/C' connections using copper wire. Switch on.
Notes.
1. The 'PROBE INPUT' must be calibrated before attempting to calibrate the retransmission output(s) – see Section 4.5C.
2. The following procedure is for calibration of retransmission output 1. Retransmission outputs 2 and 3 are carried out in a
similar manner but with the milliammeter connected to the appropriate 'O/P MODULE' terminals.
ANALOGUE RETRANSMISS
OP1 Zero
or
Enter
OP1 Span
or
Enter
18
Select Analogue Retransmission Page.
Operate for approximately three seconds to gain access to the electrical
calibration procedures within the Analogue Retransmission Page.
Advance to electrical calibration procedures.
5 Times
N o t e . 'x x x x x x' in the following illustrations is a numerical code used for
software analysis during manufacture and can be disregarded.
SECURE PARAMETERS
Retransmission Output 1,
x x x x x x
Measure the ambient temperature at the 'CELL T/C' terminals and, from
standard type K thermocouple tables, obtain the millivolt equivalent of this
temperature (a).
Subtract (a) from 0 and set the resultant value on the signal source.
Example. Ambient Temperature: 25°C
Note. The upper display on the ZMT shows the equivalent temperature of the
millivolt signal apllied, i.e. 0°C
Set the milliammeter reading to 0.00mA.
Store.
Advance to next parameter.
Retransmission Output 1, Span Calibration
x x x x x x
Measure the ambient temperature at the 'CELL T/C' terminals and, from
standard type K thermocouple tables, obtain the millivolt equivalent of this
temperature (a).
Subtract (a) from 55.80 (the theoretical millivolt equivalent of 1400°C for a type
K thermocouple) and set the resultant value on the signal source.
Example. Ambient Temperature: 25°C
Note. The upper display on the ZMT shows the equivalent temperature of the
millivolt signal applied, i.e. 1400°C
Set the milliammeter reading to 20.00mA.
Store.
Repeat for other output(s), if applicable.
(Retransmission
Zero Calibration
Millivolt equivalent: 1.00mV
Set millivolt source to: 0 – 1.00(mV) = – 1 . 0 m V
Millivolt equivalent: 1.00mV
Set millivolt source to: 55.80 – 1.00(mV) = 54.80mV