Holding Registers; Coils; Table B-3 Holding Registers - Spectris Particle Measuring Systems Airnet II 4-CH Operation Manual

Holding Registers

Holding Registers
For Airnet II, any change to the Holding registers creates a new configuration and so
stops the unit if sampling. The new configuration, when completely defined, will be
run on the next start-up.
The real-time clock is set via a "time_t" value.
The sample interval and Hold/Tare times are single registers for number of seconds to
process. This should make it easy for the host to set.
Holding Registers
40001 ushort
40002 ushort
40003 ushort
40004 ushort
40005 ushort

Coils

1 The data collection coil will enable/disable sampling. It will start a sequence of samples if the
repeat count has been set.
Read & Write: 1 = Sampling Enabled, 0 = Sampling Disabled
2
The data available coil is used to both inform the host that data is now available and to delete
the next queued data packet (if desired).
Read: 1 = Data Available, 0 = No Data Available
Write: 0 = Delete queued data element
3 The data clear coil will delete all data in the queue.
Write: 1 = Delete all queued data
4 The reset sensor coil will reset the sensor.
Write: 1 = Reset Sensor
5 & 6 The Green and Red LED (usually a single dual-color LED) can be set/read independently.
Read & Write: 1 = LED on, 0 = LED off
7 The external alarm does not exist on the Airnet II
8 The IEEE float control will change the appropriate registers (refer to the map) from a dual-
register integer with fixed scaling to a dual-register IEEE-754 Float representation. This value
can also be set into non-volatile storage via the setup interface ("set instrument float n" –
where n=1 on or n=0 off).
Read & Write: 1 = Float mode enabled, 0 = Float mode disabled
9 – 32 Spare.
Airnet® II 4-Channel Particle Sensors Operations Manual

Table B-3 Holding registers

Description (Setup)
Real Time Clock (high)
Real Time Clock (low)
Sample Interval
Hold/Tare Time
Repeat Count
Appendix B : Modbus Protocol
Comment
time_t
time_t
Seconds
Seconds
Repeat Count
B-5