Product guide

Humidity and Dew-Point Instruments
© Michell Instruments 2009-2011
44
Precision Manufacturing
WM291
Electrical Connections
Pin Pin
1 Power Supply V + 8 Output Channel 2 Ground
2 Power Supply V - 9 RS485 Data +
3 Output RS485 Ground 10 RS485 Data -
4 Ground 11 Not connected
5 Output Channel 1 Temperature + 12 Not connected
6 Output Channel 1 Ground 13 Output Channel 3 (optional)
7 Output Channel 2 RH + 14 Output Channel 3 Ground (optional)
Do not connect pin 2 (V -) to pin 4 (Ground)
Ordering Codes
To construct the order code, select the relevant feature from the tables below, starting with the base model, which is {Feature A} and then add on options to create a
string: {Feature A}+{Feature B}+{Feature C}+{Feature D}+{Feature E}+{Feature F}
Order example:
WM291+A+0+K7+N030+P070
Digital RH and temperature transmitter WM291 for wall-mounting, 4-20 mA output, dp display -40 to +100ºC, Delrin cap slotted, with stainless steel mesh fi lter, temp
range -30 to +70ºC (-22 to +158ºF)
WM291 A 0 K7 N030 P070
Signal Output {Feature B}
4–20 mA A
0–10 V B
0–5 V C
0–1 V D
0–20 mA E
Filter {Feature D}
SS sintered fi lter H2
SS sintered fi lter with tefl on coating J2
Delrin cap slotted, with SS mesh fi lter K7
Delrin cap slotted, with PTFE fi lter, white Z7
Temp Low {Feature E}
0°C (+32°F) 0000
-20°C (-4°F) N020
-30°C (-22°F) N030
3rd Output {Feature C}
Dew point: -40 to +100ºC 0
Mixing ratio: 0-500 gr/Kg 1
Absolute Humidity: 0 - 600 g/m
3
2
Specifi c enthalpy: -40 to 1500 KJ/Kg 3
Frost point: -50 to +10ºC 4
Base Model {Feature A}
Digital RH and temperature transmitter WM291
Temp High {Feature F}
+20°C (+68°F) P020
+30°C (+86°F)) P030
+50°C (+122°F) P050
+70°C (+158°F) P070
Other output scaling available on request XXXX