PC3000 Complete Installation guide iss 12 - Elektro-Trading

PC3000 - Installation Guide iss. 5
4 Channel Analogue Output Module
calibration parameters provided on the Analog_Out Function Block.
The PC 3000 analog output module employs a two point calibration scheme in order
to correct for both gain and zero offset errors. The two arbitrary calibration points
may be calibrated independently and the resultant calibration data stored. However,
it is recommended that both points are calibrated during the same calibration
session.
Calibration is performed on the currently selected range and configuration e.g. -10V
to +10V, -20mA to +20mA etc. Each range/configuration has separate calibration
data associated with it. All ranges/configurations are calibrated when the module is
despatched from the factory. For routine calibration it is only necessary to calibrate
the configured mode, voltage or current.
Calibration data is stored in EEPROM in the output module.
A channel requiring calibration due to corrupted data or a ‘raw’ channel which has
no calibration data will declare the state No_Cal (6) via the Analog_Out function
block parameter, Status_Info.
General calibration scheme
All parameters associated with calibration are included in the Analog Output Module
function block (Analog_Out).
HW_Cal_Lo_P the lower of the two calibration input values e.g 0.5V
on the 10V range
HW_Cal_Hi_P the upper of the two calibration input values e.g 9.5V
on the 10V range
HW_Cal_V the value read from the Voltmeter and converted into
a percentage of fullscale.
Cal_Mode the mode of operation for the channel.
Normally, the channel is in the Run state. During calibration
the states Hcal_Hi and Hcal_Lo followed by Save are
selected from the list.
The parameter Output_Type is used to select the output type e.g millamp, or voltage,
for which calibration is required.
Note 1: Calibration data is only sent from the PC3000 Local
Controller Module to the module under calibration when the data
changes value. All calibration parameters are classed as ‘unsolicited’
type messages. Refer to the ‘PC3000 Real Time Operating System
Reference’ chapter covering the ‘I/O sub-system’ for a full description
of ‘unsolicited’ parameters.
Note 2: From Analogue Output module firmware version 1.01
(February 1993) onwards, entering calibration mode (Hcal_Lo or
HCal_Hi) will cause the output to be set according to the default
calibration values.
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