User guide

Revision 1.0 Page 7 of 29
Warning
Please Note
The specifications of the product detailed on this
Set-Up Guide may change without notice. RDM
Ltd. shall not be liable for errors or for incidental
or consequential damages, directly and indirectly,
in connection with the furnishing, performance or
misuse of this product or document.
Ensure that all power is
switched off before
installing or maintaining
this product
Mercury 3 M & E Installation Guide
www.resourcedm.com
Switched Resistor Values
The switched resistor functionality can be turned on and off within the parameter section (P-19). When switched on, it adds the benefit of
adding further digital inputs for switches using fixed resistors. For wiring please see the ‘Switched Resistor Wiring’ section. When a
resistor is switched across the appropriate input, it signals to the Mercury to enable the switched resistor function (described for that
input) whilst still recording the probe temperature on the input.
For the function to work, it requires specific resistors depending on the probe type used;
Probe Type
Resistor
PT1000
820Ω
NTC2K, NTC2K25, 3K
590Ω
5K, 6K
1kΩ
NTC10K
2k7Ω
NTC10K(2)
2k2Ω
The resistors used must have a tolerance of 1% or better and the resistor must have a power rating of 0.25W. For improved accuracy
whilst using switched resistors RDM recommend resistors with 0.1% accuracy are used. Note: the switched resistor features will not
function when using 470R or 700R probes.
The temperature range for all probe types for probe inputs which do not have a secondary function (switched resistors) is -49
o
C to
+128
o
C. Inputs which have use the secondary (digital) function are restricted to -42
o
C to +60
o
C. If the full temperature range is required
on all inputs and no switch resistor features are needed then please see Switch Resistor parameter P-19.
Note: switched resistors will operate in LT (Low Temperature) and HT (High Temperature) applications using PT1000, NTC2K or
NTC2K25 probe types only. For all other probe types the switched resistor inputs will work in HT applications only.
Transducer Input – Electronic Expansion type only
There are two possible inputs that can be used for a transducer on the Mercury 3 E variant; either using the 0-10v or the 4-20mA. Please
consult the I/O Connections for wiring. Depending on the type of transducer (0-10v or 4-20mA) the physical input can be chosen using p-
17. The parameters on the controller (p-35 & p-36) must then be set so the transducer is read.
Ordering Information
When ordering a Mercury Mk 3 controller the following ordering scheme can be used to purchase the desired hardware configuration.
PR0740- X Y Z CAS
X
Description
M
Mechanical Relay
E
Solid State Relay
Y
Description
D
Local/ Integral Display
R
Remote Display
Z
Description
IP
Ethernet Comms
232
RS232 Comms
Example
To order a Mercury MK3 with a Solid state relay (for EEV’s), Remote display and IP comms;
PR0740 – E R IP CAS