Holding Registers
Appendix D Modbus
IsoAir 310P Aerosol Particle Sensor Operations Manual
Page D-5
Holding Registers
Like the coils, spares are in place between the "standard" registers and those that are
specific/optional to the IsoAir 310P. The optional IsoAir 310P register is the same as the
optional coils (Digital Outputs) but places them all in a single register for ease-of-use.
Also the "Mask Write Holding register function" will operate on this holding register
only.
For IsoAir 310P, 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.
Note that the Hold/Tare time for the IsoAir 310P is the time it will delay between the
pump having coming up to specified flow and starting the first sample.
Table
D-3
Holding registers
Holding Registers
Description (Setup)
Comment
40001
ushort
Real Time Clock (high)
time_t
40002
ushort
Real Time Clock (low)
time_t
40003
ushort
Sample Interval
Seconds
40004
ushort
Hold/Tare Time
Seconds
40005
ushort
Repeat Count
Repeat Count
Spare
ushort
27 spare registers
Reserve future "common" registers
40033
ushort
Digital Output control
Set all digital outputs
