Page 5-10
MiniCapt Remote Microbial Air Sampler Operations Manual
Chapter 5 Modbus Protocol
Coils
Coils
Like the holding registers, spares are in place between the “standard” coils and those
that are designated as specific/optional. There are no specific/optional coils defined
for the MiniCapt.
00/01:
The data collection coil will enable/disable sampling.
Read: 1=Sampling Enabled, 0=Sampling Disabled.
Write: 1=Start Sampling, 0=Stop Sampling.
00/02:
The data available coil is used to both inform the host that data is now available
and to delete the queued data packet (if present).
Read: 1=Data Available, 0=No Data Available.
Write: 0=Delete queued data element, 1=No effect,
If the queue size setting has been set to one, the sample data will always
represent the last real-time data packet and the data deleted will be the only data
present.
If the queue size setting is set greater than one, the oldest data packet in the
queue will be deleted.
00/03:
The data clear coil will delete all data in the queue.
Read: Always 0
Write: 1=Delete all queued data, 0=No effect
00/04:
The reset sensor coil will reset the sensor.
Read: Always 0
Write: 1=Reset sensor, 0=No effect
00/05:
Green Status LED. Not applicable for MiniCapt.
Read: 1=LED On, 0=LED Off
Write: 1=LED On, 0=LED Off
00/06:
Red Status LED. Not applicable for MiniCapt.
Read: 1=LED On, 0=LED Off
Write: 1=LED On, 0=LED Off
00/07:
External Alarm. Not applicable for MiniCapt.
Read: Always 0
Write: No effect
00/08:
IEEE-754 Float. The float control will change the specified registers from a dual-
register integer with fixed scaling to a dual-register IEEE-754 float representation.
The IEEE-754 version is likely to yield better resolution but it is not part of the
official Modbus specification.
Read: 1=Float mode enabled, 0=Float mode disabled
Write: 1=Float mode enabled, 0=Float mode disabled
