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PRESYS
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Instruments
By pressing ENTER after the mnemonic CJC the program automatically starts
computing the cold junction temperature. During this period the display flashes the
mnemonic CAL.
After approximately 16 seconds the program completes the computation of the
cold junction temperature and shows the result on the display, in °C.
This value is a first approximation for the cold junction temperature. The user
should then accurately measure the I/O terminal temperature and correct the value
submitted by the program in the usual way of introducing parameter values as
explained in section 3.2 on Configuration.
Upon completing those two steps the input calibration for any type of
thermocouple is concluded.
Then return to normal operation mode moving back until level zero.
Calibration of 2- or 3-wire RTD input
In order to calibrate the 3-wire RTD input, connect precision resistors of values
listed in table 9 between terminals 4 and 5 with terminals 5 and 6 short-circuited.
In case a precision decade resistance is available, make sure the three
connection wires have exactly the same length, gauge and material.
No calibration procedure is available for a 2-wire RTD input. This is
automatically carried out when the 3-wire RTD input is calibrated.
Output calibration
For output calibration follow the procedure described to calibrate the analog
outputs 1 and 2.
The analog outputs will be calibrated by the Controller themself.
Output 1 will be calibrated by input 1 and output 2 will be calibrated by input 2.
The hardware configuration of the input should be the same as that of the
output (0 to 5V, 0 to 10V or 0 to 20mA) since the Controller themself will be
measuring the output signal. Therefore, check that the configuration of the internal
jumpers in the optional Output Module and in the CPU Board match the
corresponding input and output types.
DCY - 2057 Pressure Controller
Reference
100.000 Ω
300.000 Ω
Table 9 - Required resistances for the calibration
of a 3-wire RTD input
Mnemonic
C.100r
C.300r
Maintenance
Page 62
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