Module power and miscellaneous i/o – Trane RTWA 70-125 TON User Manual
Page 51
RLC-SVD03A-EN
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Module Power and Miscellaneous I/O
2.
Has its negative terminal tied to chassis ground.
If the intended source does not meet the above requirement, an isolation
module must be used
The 4-20mA/2-10VDC inputs may be tested in the following ways:
1.
Enable External Chilled Water Setpoint and/or External Current Limit Set-
point in the Operator Settings Menu. Advance display to Active Chilled
Water Setpoint or Active Current Limit Setpoint to observe the respective
setpoint in the Chiller Report.
2.
With all wiring in place, apply an external voltage or current to the Exter-
nal Chilled Water Setpoint inputs (TB1-4 & 5) or the External Current Limit
Setpoint (TB1-7 & 8). The voltage measured at the terminals and the
resulting setpoint, as read on the CLD, should agree with the
for
Chilled Water Setpoint inputs and
for Current Limit Setpoints
inputs. Be sure to wait long enough when reading the display as the val-
ues are slew rate limited.
3.
Disconnect all wiring to these inputs. The setpoints should slew back to
the chiller's Front Panel settings.
4.
Disconnect all wiring and install fixed resistors of values near those
shown in the following tables across TB1-3,5 or TBl-6,8. The resulting set-
points should agree with the table values.
Table 17
Input Values vs. External Chilled Water Setpoint
INPUTS
Resist (ohms)
Current (ma)
Voltage (Vdc)
Resulting Chilled
Water Setpt (F)±4F
94433
4.0
2.0
0.0
68609
5.2
2.6
5.0
52946
6.5
3.2
10.0
42434
7.7
3.9
15.0
34889
8.9
4.5
20.0
29212
10.2
5.1
25.0
24785
11.4
5.7
30.0
21236
12.6
6.3
35.0
18327
13.8
6.9
40.0
15900
15.1
7.6
45.0
13844
16.3
8.2
50.0
12080
17.5
8.8
55.0
10549
18.8
9.4
60.0