Protocol: Rotorsynctest  Sequence: rotorsynctest.c  Apptype: solidseq1d

Description: 

Test the rotorsync and xgate commands with a scope. This sequence
places xgate(1.0) before the spare-one line trigger and applies a
pulse 4.0 us later. A second pulse follows "periods" rotorperiods
after the first. Athird pulse folows after a 10.0 us delay so as
to unambiguously identify the second pulse. 

Setup: 

Install the rotorsync hardware on VNMRS. A multipin-to-BNC cable
is placed between Tachometer on the Pneumatics Router and the 
Tach Out BNC Tee on the MAS Speed Controller. A second BNC cable
is placed between the Tach Out BNC Tee and the Ext Trig port  
On the Console Interface Panel. 

This test requires a Solids setup with a working probe and 
MAS Speed Controller. The "Tach Out BNC" can also be replaced by 
a square-wave signal generator if a Solids probe is not available. 

For this test add a second Tee to the Tach Out BNC Tee (3 cables 
total on this port) and place a BNC cable between this Tee and 
channel 1 of a scope. Set 1 mega-ohm resistance for this channel
(not 50 ohms!). 

Place a second BNC cable between the "Available 1" output of 
CH1 on Console Interface Panel and channel 4 or the 
external trigger of the scope. Be sure the scope trigger is 
set to this channel. 

Remove all cables from the attenuator board outputs 297, 298
299 and 290. 

Place a third BNC cable between the intended observe channel 
on the attenuator board (based on probeConnect) and channel 
2 of the scope. The observe channel number is in the upper 
right of the obs box on the Channels page of the Acquire tab. 
1 = 297 2 = 298 3 = 299 and 4 = 290. 

Select the Settancpx protocol (type Settancpx on the commandline)
and then select the Rotorsynctest protocol (type Rotorsynctest 
on the commandline). 

Set sw = 5e6, nt = 1e6, d1=0.02s, srate = 10000
and bs = 'n'. Set the spin rate to 10 kHz and start the rotor
spinning with spin control. Then start the acquisition.  

If the acquisition starts and runs continuously xgate(1.0) is 
functioning properly. If the acquisition does not start xgate(1.0)
is defective or the cables to the MAS controller are incorrect. 
Check the cable between the Console Interface Panel (Ext Trig) 
and the Tach Out BNC. 

Observe channel 2. The first pulse should be triggering 2 or 4 us 
after the beginning of the trace, depending on the polarity of 
the scope trigger. A second pulse pair should follow after a 
delay of 1.0/srate. If the MAS speed is stable there should be an 
approximate +/- 500 ns (or less) jitter in the second pulse. If there
is no pulse or if the time is not 1/srate, the rotorsync 
command is not working. Check the cable between the Pneumatics
Router and the MAS Speed Controller.

Set periods = 2.0.  The delay to the second pulse should be
2.0/srate. In general if periods = N the delay should be 
N/srate. 

Observe channel 1. One should see a stable square wave 
with a positive edge triggered at the beginning of the 
trace. If the MAS speed is stable the second rising edge 
should have a jitter of +/- 500 ns or less, similar to the
second pulse. If the pulse jitter of the previous step
does not match the jitter of the trace, there is a problem
with the rotorsync command. 

When finished remove all of the scope cables and the second 
Tee on the Tach Output. Leave the cables to the Pneumatics
Router and the Console Interface Panel.

Parameter Groups:

90X:  Module:  no
Sequence:  onepul.c    
Description:  Provides a 90-degree pulse on obs that can be used 
              as a preparation pulse. Also used to store the obs 
              calibration.
Parameters:  Channels Page
      aX90  - the amplitude of the pulse.
      pwX90 - the pulse length.

parameter: 

periods - The number of rotorperiods between the first and 
          second pulses of this test. 



