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Entek IRD 6687 Protection Monitor
6687 Monitor
Calibration and System OK Relay Test
The following steps show you how to test the calibration for channel 1. They also test the
function of the System OK relay. To test the calibration for channel 2, substitute the
channel 2 terminals.
1.
Connect a known DC voltage source set for positive polarity to the channel 1 input
terminals (1 and 2). (See diagram with “Signal Inputs for Testing” on page 26.)
2.
Connect a multimeter to the channel 1 4–20 mA recorder terminals (5 and 6).
3.
Set the input signal to the voltage at FS LO. Refer to “Signal Inputs for Testing” on
page 26 for details.
4.
Look at the 6687 front panel display, and note the digital value for channel 1. The
digital value for input channel 1 should be FS LO ± 2.5% of full scale. Remember that
the monitor displays the input channel 1 value when the indicator (a dash) is over the
input channel 1 bar graph.
5.
Look at the multimeter attached to the 4–20 mA recorder terminals. The meter should
read 4 mA ± 4.5% of full scale.
6.
Increase the DC voltage input to the voltage at FS HI.
7.
Look at the 6687 front panel display, and note the digital value for channel 1. It should
be the same as the FS HI setting ± 2.5% of full scale.
8.
Look at the multimeter attached to the 4–20 mA recorder terminals. The meter should
read 20 mA ± 4.5% of full scale.
9.
Test the state of the System OK relay terminals (25 and 26). The System OK relay is
always in failsafe condition, so it should be in the energized (open) position.
10. Change the input signal voltage so that it goes outside the TX LO or TX HI limits (“TX
OK submenu” on page 22). Check to see that the TX FAIL message appears on the
monitor, and that the both display and 4–20 mA output go to 0 (zero).
11. Test the state of the System OK relay terminals (25 and 26). The state should change to
closed when you change the input signal, indicating transducer failure. Note that the
System OK relay is not subject to the GLOBAL alarm delay (“DELAYS submenu” on
page 24).
Repeat this process for channel 2.
