CTI 2557-A Installation and Operation Guide
7
2.4
Configuring the Module
The Model 2557-A must be configured for 10 Ohm copper, 100 Ohm platinum or 120 Ohm nickel
RTDs (2, 3 or 4 wire) or millivolt range and digital filtering/no filtering mode before wiring the input
connectors and inserting the module into the I/O base.
Configuring the module is a two step process. Hardware jumpers are positioned to provide proper gain
and lead wire compensation for either 3 wire or 4 wire RTDs. DIP switches are provided to inform the
microprocessor the changes made to the hardware.
Changing the module input channel configuration involves the following steps:
1.
Selecting temperature or millivolt measurement via DIP switch
2.
Selecting 3 or 4 wire compensation
3.
Selecting 100 Ohm platinum, 120 Ohm nickel or 10 Ohm copper input mode for each channel
4.
Selecting standard login mode (16WX) or Advanced Operating Mode
5.
Selecting digital filtering or no filtering for the module
6.
Selecting degrees C or F for the module
7.
Selecting Engr units or SCALE units for module
8.
Logging the configuration jumper settings for future reference
Each of these steps is described in the following sections.
2.4.1
Selecting Temperature or Millivolt Input
No hardware changes are required for millivolt inputs. To select millivolt input mode for an input turn
OFF the M and L switch for the input channel. (See Figure 10.) To select a particular RTD probe for
each channel configure the M and L switch.
M
L
0
0
Millivolt
0
1
10
0
Cu
1
0
100
0
Pt
1
1
120
0
Ni
NOTE:
Each channel contains a jumper to select between 2, 3 and 4 wire RTD elements. (See Figure
10, JP68). For 2 wire and 3 wire RTDs no change is required. For 4 wire RTDs the jumper
should be removed and placed on a single pin for storage.
NOTE:
As shipped, all input channels are configured 100 Ohm platinum, 3 wire RTDs, degrees
Centigrade and digital filtering enabled.
