Particle Measuring Systems LASAIR II 310, Руководство оператора

Страница: 203 / 231

Page Page J-6 J-6 LASAIR LASAIR II II Operator’s Operator’s Manual Manual
Appendix J: 4-20 mA Input and Output Appendix J: 4-20 mA Input and Output
4–20 mA Out Status Channel 4–20 mA Out Status Channel
Channel 1 can be used to monitor the following information: Channel 1 can be used to monitor the following information:
••
Power On/Off Power On/Off
••
Sampling/Idle Sampling/Idle
••
Laser Error Laser Error
•• Pump Error Pump Error
••
Particle Alarm Particle Alarm
4-20 mA Out Particle Channel 4-20 mA Out Particle Channel
The status channel can be examined either as a single level check, or as bit The status channel can be examined either as a single level check, or as bit
mapped error bits. In the simplest test, the output will be 18.25
mapped error bits. In the simplest test, the output will be 18.25 mA if the box is mA if the box is
on, no alarms are set, and on, no alarms are set, and sampling is taking place. If something is wrong, the sampling is taking place. If something is wrong, the
output will be 17.5 mA or less. output will be 17.5 mA or less.
A more complex decoding is a combination of level sensitive and bitmap. If the A more complex decoding is a combination of level sensitive and bitmap. If the
LASAIR II is on, a base level of
LASAIR II is on, a base level of 7 7 mA is output. If the LASAIR II is off, then mA is output. If the LASAIR II is off, then
the output current will be less than 7 mA. the output current will be less than 7 mA.
The status parameters are bit encoded with 0.75 The status parameters are bit encoded with 0.75 mA per bit, and the bits are mA per bit, and the bits are
assigned as follows: assigned as follows:
Manifold Position Manifold Position
The manifold position is output at 4 The manifold position is output at 4 mA if the AM-II is not being used. If it is mA if the AM-II is not being used. If it is
used, then each channel is 0.25 mA. Thus channel 1 is 4.25 mA, and channel used, then each channel is 0.25 mA. Thus channel 1 is 4.25 mA, and channel
32 is 12 mA.
32 is 12 mA.
Notes on Setting Particle Scale Factors Notes on Setting Particle Scale Factors
Channel Particle Scale Considerations Channel Particle Scale Considerations
The maximum counts that can be monitored is the same as the scale factor. In The maximum counts that can be monitored is the same as the scale factor. In
other words, if the scale for channel 1
other words, if the scale for channel 1 is set to 100, then the is set to 100, then the output will be 20 output will be 20
mA, when the counts read 100. If the counts are 105, or 2000, the output will mA, when the counts read 100. If the counts are 105, or 2000, the output will
stil still be 20 l be 20 mA. mA.
Sa Sam mpl plin ing_ g_on on bi bit t 1 1 = = 0. 0.75 m 75 mA A
P Pu um mp pO OK K b biit t 2 2 = = 1 1..5 5 m mA A
L LaasseerrO OK K b biit t 3 3 = = 3 3..0 0 m mA A
Particle Not Alarmed bit 4 = 6.0 mA Particle Not Alarmed bit 4 = 6.0 mA
When LASAIR II is on, the base-level output is 7 mA When LASAIR II is on, the base-level output is 7 mA