Model 4900 Series Remote Airborne Particle Counters
0.3 or
0.5µm minimum threshold setting
0.1 or 1.0
cfm flow rate
Two size
channels
4–20mA
output
Delayed
alarm
Connecting remote particle counters to your scada system has never been easier than with Met One’s R4900 Series of miniature particle counters. Their small size allows them to be mounted much nearer to critical monitoring areas at many locations around the cleanroom. All you need to provide is a vacuum source and a communication line. The R4900 Series uses the industry standard 4–20mA interface. Loop current is driven by voltages between 15 and 30 VDC. The sensors use an RS485 serial interface, for programming count time, hold time, alarm level, alarm delay, and scaling for the 4–20mA output. The programming is retained through power off and on cycles. A user-defined alarm level can be set for high counts on channel one. When high counts trigger an alarm, the LED on the counter flashes and an alarm signal is set at the connector. The alarm can be set to trip after the level is exceeded the first time or after the second through ninth time counts exceed the level. The alarm automatically resets at the start of the next count cycle.
| Connector (DB-15 Female Connector) | |
| 1 | Ground |
| 2 | Alarm, open drain FET |
| 3 | Channel 1 current out |
| 4 | Channel 2 current out |
| 5 | +24 VDC loop power |
| 6 | RS485A |
| 7 | N/C |
| 8 | RS485B |
| 9 | Reserved |
| 10 | Reserved |
| 11 | Reserved |
| 12 | Reserved |
| 13 | Ground |
| 14 | Reserved |
| 15 | +6 VDC Power |
Specifications
| Size Channels | |
| R4903: Ch 1/Ch 2 | 0.3/0.5 micron |
| R4905, R4915: Ch 1/Ch 2 | 0.5/5.0 micron |
| Flow Rate | |
| R4903, R4905 | 0.1 cfm |
| R4915 | 1.0 cfm |
| Flow Control | critical orifice; requires 18" Hg vacuum |
| Light Source | laser diode (30,000 hours mean time between failure) |
| Coincidence Loss | |
| R4903, R4905: | 5% at 2x106 particles per cubic foot |
| R4915: | 5% at 4x105 particles per cubic foot |
| Inlet Pressure | ambient to 0.1" Hg vacuum |
| Indicators | power and calibration/alarm LEDs |
| Power | 6 Vdc (+/-10%) at < 250 mA |
| Loop Supply | 15–30VDC |
| Output | 2 size channels; 0mA on sensor fail or no power |
| Output Scaling | program from 10–999,999 counts full scale |
| Alarm Output | open collector FET max sink current
(on) 150 mA; Max V.C. voltage (off) 30 VDC |
| Alarm Delay | 1–9 high count levels |
| Weight | 10.7 ounces (0.30 kg.) |
| Inlet Port | 1/8" ID |
| Outlet Port | 1/4" ID |
| Environment Operating | 55 to 84°F (12 to 29°C), 20 to 95% R.H., noncondensing |
| Storage | -10 to 160°F (-23 to 70°C), up to 98% R.H., noncondensing |
Options
Switching power supply
(supports up to 16 sensors, 6 VDC, 5 A)
Wall plate power adapter for
8–30 VDC input (use one wall plate per sensor) (can
also provide loop current with 15–30 VDC)
Power adapter for 8–30
VDC input (use one per sensor without wall plate)
Ordering
Guide
When ordering, specify the
following:
Model R4903, R4905, or R4915
Second size channel if
different than standard
Options as required