Checking Inputs And Outputs; Digital Inputs; Analog Inputs - Temperature - York YCWL0056SE Installation Operation & Maintenance

FORM 201.26-NM1
ISSUE DATE: 1/19/2018

CHECKING INPUTS AND OUTPUTS

Digital Inputs

Refer to the unit wiring diagram, Elementary Wiring
Diagram on page 68. All digital inputs are connect-
ed to J13-1 of the I/O board. The term "digital" refers
to two states – either ON or OFF. As an example, when
the flow switch is closed, 30VDC will be applied to
J13, pin 5 (J13-5) of the I/O board. If the flow switch is
open, 0VDC will then be present at J13-5.
Pin 1 of J13 is an unregulated 30VDC source used
to supply the DC voltage to the various user contacts,
Unit Switch, flow switch, etc. This DC source is fac-
tory wired to CTB1, terminal 13. Any switch or contact
used as a digital input would be connected to this ter-
minal, with the other end connecting to its respective
digital input on the microboard. Any time a switch or
contact is closed, 30VDC would be applied to that par-
ticular digital input. Any time a switch or contact is
open, 0VDC would be applied to that particular digital
input.
JOHNSON CONTROLS
SECTION 9 – SERVICE AND TROUBLESHOOTING
Typically, voltages of 24 to 36VDC could be measured
for the DC voltage on the digital inputs. This voltage is
in reference to ground. The unit case should be suffi-
cient as a reference point when measuring digital input
voltages.
Analog Inputs – Temperature
Refer to the unit wiring diagram, Elementary Wiring
Diagram on page 68. Temperature inputs are con-
nected to the microboard on plug J6. These analog
inputs represent varying DC signals corresponding to
varying temperatures. All voltages are in reference to
the unit case (ground). The following pages show the
connections for the temperature sensing inputs.
9
159