8
Installation Notes:
1)
A resistor may be wired remotely across the analog output terminals to convert analog
output milliamp current to a voltage. Use Ohm’s Law to calculate the proper resistance
for the desired voltage based upon the 1250-LTC’s rated output current.
2)
Maximum analog output load resistance: 0-1mA = 10K ohms; +/-1mA = 10K ohms;
0-2mA = 5K ohms; 4-20mA = 500 ohms.
3)
Models with 4-20 mA analog output options must have an EXTERNAL LOOP POWER
SOURCE of 10.0 VDC minimum, 24.0 VDC maximum, in series with the current loop.
The INCON Model 1945 Power Supply is recommended for these installations,
(See Figure 1.3, page 7).
4)
When additional remote indication is needed, several 1250-LTC’s may be wired in
parallel to the same transmitter. The 1250-LTC can also be connected via its serial port to
the INCON model RD-4 Remote Display unit.
5)
The 1250-LTC and the synchro transmitter MUST BE WIRED TO THE SAME AC
SOURCE. Do not remove the jumpers from terminals E and F.
6)
A wire jumper or keyswitch may be installed between terminals 3 & 4 to prevent the
program from being changed. When these terminals are jumpered the menu will read
“
EP
-x” instead of “
OP
-x”, which indicates that you can Examine each Parameter, but not
change them.
7)
After installation and programming, install the rear terminal guard with screws provided.
8)
For models with serial options, plug the cable onto the card edge with the red stripe
towards the outside of the case.
Application Bulletins:
1)
If there is a large component of AC “ripple” present on the 1250 analog output, check the
isolation of all wiring with respect to earth ground. R1, R2, S1, S2, and S3 should
measure infinite resistance to earth ground. In applications where external isolation is not
sufficient, the
Input Isolation Option (-I)
is required to break the ground path that causes
this ripple. See Application Bulletin #000-1150 for more detailed information.
2)
Analog outputs of 0-1mA, +/-1mA, and 0-2mA can be changed in the field to any one of
the other two (see Table 1.3). The configuration jumpers are located on the bottom PCB.
See Application Bulletin #000-1151 for more detailed information.
Table 1.3 Analog Output Configuration Jumpers
Output Signal:
J8
J10
J12
J13
0-1mA Jumped
Jumped Jumped
+/-1mA Jumped
Jumped
Jumped
0-2mA
Jumped
Jumped