Getting Familiar With The EGM-4
EGM-4 Operator's Manual – Version 4.19
- 12 -
Environmental Sensor Inputs (I/O Ports)
The EGM-4 has 2 environmental sensor inputs (I/O) to allow external sensors (i.e. soil
respiration chamber, CPY-2/CPY-3/CPY-4 Canopy Assimilation Chambers, TRP-1
Temperature/PAR Probe, PAR-1 Probe, etc.) to be used simultaneously. All sensor inputs
lines require 0-1V input. Note, the sensor inputs are displayed in mV (i.e. 0-1,000 mV)
instead of Volts.
If one of our environmental sensors is used with the EGM-4, it must be plugged into the
instrument prior to turning it on. The EGM-4 automatically detects the sensor connected as a
result of code resistors which are fitted to the 15 pin D Connector between pins 1 and 6. The
code resistors for our environmental sensors are as follows:
Probe Type
PP Systems Sensor
Code Resistor
0
The EGM-4 is being used as a stand
alone IRGA (no external sensors
connected)
Not applicable. This is
determined by keypad
selection.
1
STP-1 Soil Temperature Probe
100 K
Ω
2
Not Applicable. Used to be used with
older sensors.
56 K
Ω
3
TRP-1/TRP-2 Temperature/PAR Probe
36 K
Ω
4
PAR-1/PAR Sensor
27 K
Ω
5
Not Applicable. Used to be used with
older sensors.
20 K
Ω
6
Not Applicable. Used to be used with
older sensors.
15 K
Ω
7
Steady State Porometer (PMR-5)
Not applicable. This is
determined by keypad
selection.
8
SRC-1 Soil Respiration Chamber or CPY-
2/CPY-4 Canopy Assmiliation Chamber
(Closed System operation)
9.1 K
Ω
9
OP-1/OP-2 O
2
Sensor
20 K
Ω
10
Not Applicable. Used to be used with
older sensors.
5.6 K
Ω
11
CFX-1 Open System Soil Respiration
Chamber or CPY-3 Canopy Chamber.
4.3 K
Ω
12
CPY-4 Canopy Assimilation Chamber
(Closed System Operation)
9.1 K
Ω
Note.
When the EGM-4 is supplied with a PP Systems accessory (i.e. SRC-1, CPY-4, etc.),
the probe type will be set at the factory based on the accessory supplied. Therefore, it may
be necessary to change the probe type if required. The probe type can be changed from the
menu on page 30. if required. See
on page 13 for analog output pin-
outs and location for code resistor placement (Pin 1).
