Panametrics DigitalFlow XMT868i, Руководство по обслуживанию, Страница: 10 / 74

Chapter 1. Calibration
2 DigitalFlow™ XMT868i Service Manual
1.3 Calibrating and Testing Analog Outputs
Every Model XMT868i flowmeter includes two built-in analog outputs (A and B) at terminal block J1 , which is
designated as Slot 0 . Additional analog outputs may be added to the Model XMT868i by installing an appropriate
option card in Slot 1 . This option card contains two analog outputs, which are also designated as A and B .
Before beginning calibration, an ammeter must be connected to the desired analog output. Both the zero-point and
full-scale values for all of these outputs must be calibrated. After calibrating the outputs, which have a resolution of
16.0  A (0.1% full scale), their linearity should be tested.
Note: The zero point of the analog output may be set at either 0 mA or 4 mA. However, the calibration always uses
the 4 mA point, as the meter extrapolates this value to obtain the 0 mA point.
1.3.1 Preparing for Calibration
Prepare for calibration by inserting an ammeter in series with the load on the desired output. Refer to Figure 1 and
Figure 4 on page 12 to identify the OUT(+) and RTN(-) pins for the desired output.
Figure 1: Ammeter Connection (Output A)
Terminal Block J1 (Slot 0)
B
RTN
B
SIG
A
RTN
A
SIG
4 1
+
-
Ammeter
Load