West Control Solutions MRC 8000 - Manual (Page 56)

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terminal 2 is negative. Press the SCROLL key and the display will indicate 4 milliamps. Use
the UP and/or DOWN key to increase or decrease the current output in 1 mADC steps from 0
to 20 mADC.
The current output reading should be
±
0.1 mADC at any output value. A
±
5 % of span
adjustment for the current output(s) is provided by using the potentiometer adjacent to the
current output on the Current Output board. See Appendix A-4 (page 65). To exit the test,
press the SCROLL key and tSt7 will be displayed. The existence of a mADC current
output is dependent upon the hardware configuration.
5.5.8 TEST 8 PEN/CHART MOTOR TEST
This test allows the operator to verify that pen and chart motors are functioning properly. No
special test equipment is required.
With tSt8 displayed press and hold the DOWN key, then press the SCROLL key. The display
will show ALL while the test is in progress. This test functions automatically. The chart speed
will be at maximum, 72 seconds per revolution. Starting at the current pen position, pen 1 will
move (sweep) upscale for about 5 seconds, then downscale for about 5 seconds. Pen 2 (if
provided) will sweep in the opposite direction. The pens will continue to cycle until the test is
exited. To exit, press the SCROLL key. The display will show tSt8.
5.5.9 TEST 9 AUXILIARY INPUT TEST
This test allows the operator to verify that the auxiliary input(s), if specified, pen position
feedback input(s) are functioning properly.
Auxiliary inputs are the remote setpoint and position proportioning options. With tSt9 dis-
played, press and hold the DOWN key, then press the SCROLL key. The display will show
Ai1, Auxiliary Input 1. By pressing the DOWN key, the instrument will sequence through the
selections for testing: Ai2 then back to Ai1. With the desired input selected, press the
SCROLL key. The corresponding value will be displayed. To terminate a particular test, press
the SCROLL key. The display will show tSt9.
5.5.10 TEST A COMMUNICATIONS HARDWARE TEST
(COMMUNICATIONS OPTIONAL)
This test allows the operator to verify that the communications hardware is functioning
properly.
With tStA displayed, press and hold the DOWN key then press the SCROLL key. The display
will indicate SEnd. Press the DOWN key to toggle the display between SEnd and rEC . With
the desired function selected, press the SCROLL key. In the SEnd (send or transmit) mode,
the instrument will repeat the following sequence. First the transmitter will output a logic 1 on
the line for one second. Next the transmitter will change the logic level to 0 for one second.
Then the transmitter will disable for one second. In the rEC (receive) mode, the transmitter is
continuously disabled. In either mode, the instrument will monitor the line and display rEC1
when a logic 1 is on the line or rEC0 when a logic 0 is on the line . In the SEnd mode, the
instrument will display rEC when the transmitter is disabled. To perform an internal test and
verify the basic operation of the hardware, place the instrument in the Send mode and verify
that the display cycles through rEC1, rEC0, and rEC. To verify that the transmitter functions
properly, two LED’s, each with a current limiting resistor, can be connected with opposite
polarity observed to the TB 2 terminals 1 and 2. The following three states should be ob-
served: one LED On, then the other LED On, then both Off. Alternately, a load resistor can be
placed on the terminals, and observe that the voltage generated across the load resistor is as
follows: >+3 VDC, then >-3 VDC, and then 0 VDC.
Another method, to test the communications hardware, would be to connect one or more
instruments in the Receive mode to an instrument in the Send mode. All of the instruments in
the Receive mode should have their displays alternating in sync with the instrument in the