Series 655T/656T Transmitter User's Manual mV/TC Input
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Table 3A: Input Range/Type Selection - DIP Switch Settings
INPUT RANGE
S1
S2
S3
S4
S5,6,7
2
J TC
0
0
0
0
NA
K TC
1
0
0
0
NA
T TC
0
1
0
0
NA
R TC
1
1
0
0
NA
S TC
0
0
1
0
NA
E TC
1
0
1
0
NA
B TC
0
1
1
0
NA
N TC
1
1
1
0
NA
0-1.0V
3
0
0
0
1
NA
0-500mV
3
1
0
0
1
NA
0-250mV
3
0
1
0
1
NA
0-125mV
3
1
1
0
1
NA
62.5mV
0
0
1
1
NA
31.3mV
1
0
1
1
NA
15.6mV
0
1
1
1
NA
Reserved
1
1
1
1
NA
Notes (Table 3A):
1. NA = No Application; Don’t Care; 0 = Switch Open/OFF;
1 = Switch Closed/ON.
2. Note that switches SW5, SW6, SW7 have no function and
are reserved for future use.
3. The unit will permit calibration below 0V, down to -65mV
typical, for these ranges.
4. The economy Model 656T-E600 only provides support for the
three ranges indicated in
BOLD
(J, K, 0-125mV).
Table 3B: Miscellaneous Options - DIP Switch Settings
MISCELLANEOUS
OPTIONS
SW
8
SW
9
SW
10
SW
11
SW
12
Break Detection ON
1
Break Detection OFF
0
TC Break Downscale
1
TC Break Upscale
0
CJC OFF
1
CJC ON
0
Linearization
3
OFF
1
Linearization
3
ON
0
Configuration Lock OFF
1
Configuration Lock ON
0
Notes (Table 3B):
1. 0 = Switch Open/OFF; 1 = Switch Closed/ON.
2. The Default Configuration is all switches OFF (0). This
corresponds to the factory default configuration of J TC type,
TC Break OFF, TC Break Upscale, CJC ON, Linearization
Enabled, and Reconfiguration Locked Out.
3. The economy Model 656T-E600 does not support TC
linearization (set via SW11) and this setting will be ignored.
These units were packaged with one or more plastic covers for
installation over the DIP switch openings. Do not install the DIP
switch cover(s) until you have completed the zero and span
configuration procedure outlined in the following section. This is
done to maintain access to the Configuration Lock switch
(SW12), which should be locked following zero and span
reconfiguration to help prevent inadvertent miscalibration or
tampering in the field.
ZERO AND SPAN CONFIGURATION
IMPORTANT:
You must set your DIP switches according to your
application prior to configuring the zero and full-scale input points
as described below (see above).
UNLOCK RECONFIGURATION:
Reconfiguration of zero and
full-scale is locked out by default and must be unlocked before
making adjustments to zero and full-scale--DIP switch 12 must be
set ON to unlock the front-panel Z/FS toggle switches.
After setting the DIP switches as required for your
application, you may optionally re-scale your input range to the
output 4mA and 20mA endpoints as described here.
Configuration of the zero & full-scale I/O points (essentially input
to output scaling) i
s accomplished via the transmitter module’s
“Z” and “FS” Up/Down toggle switches located on the front panel
(see Drawing 4501-779).
Equipment Required
An accurate input source adjustable over the range desired
for zero and full-scale is required. A thermocouple calibrator may
also be used. An accurate current or voltage meter is also
required to monitor the output level. For best results, the input
source and output meter must be accurate beyond the required
specifications. For voltage inputs, use a voltage source with an
output impedance of 100
or less.
In the absence of a thermocouple calibrator, a convenient
method of configuring the TC input would be to use a precision
mV source with the module’s CJC set to OFF. Using this method
allows the mV source to be wired directly to the input terminals
using copper wires. The module’s cold junction compensation is
turned off and the mV values applied to the input are the
equivalent thermoelectric voltages that correspond to the
minimum and maximum temperatures of your desired input range
and are specific to each TC type. Refer to Table 4 of the
following page for a list of thermocouple voltages at specific
temperatures. After setting zero and full-scale in this manner, the
CJC switch should be returned to the ON position to enable cold
junction compensation.
Transmitter Zero/Full-Scale Configuration Procedure
CAUTION:
Input levels outside of the nominal range of the
selected input will not be accepted for configuration of zero or full-
scale. Since input levels cannot be validated during field
programming, entering incorrect signals may produce an
undesired output response.
Note:
The transmitter’s input range/type, TC break on/off, TC
break up/down direction, CJC on/off, linearization, and zero/full-
scale reconfiguration lock/unlock is set via the DIP switches.
Each input range is already factory calibrated and scaled to the 4
to 20mA output by default. However, you may use the front panel
toggle switches to scale virtually any part of the nominal input
range to the 4-20mA output range. For example, use the 0 to
200
C portion of the type J TC input to drive the 4 to 20mA output
range--this configuration will be used as an example in the
following procedure.